Next Article in Journal
Black Plastic Film Mulching Increases Soil Nitrous Oxide Emissions in Arid Potato Fields
Previous Article in Journal
Adolescent Depression from a Developmental Perspective: The Importance of Recognizing Developmental Distress in Depressed Adolescents
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Comparison of Long COVID-19 Caused by Different SARS-CoV-2 Strains: A Systematic Review and Meta-Analysis

1
Department of Epidemiology and Biostatistics, School of Public Health, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing 100191, China
2
Institute for Global Health and Development, Peking University, No. 5, Yiheyuan Road, Haidian District, Beijing 100871, China
3
Global Center for Infectious Disease and Policy Research & Global Health and Infectious Diseases Group, Peking University, No. 38, Xueyuan Road, Haidian District, Beijing 100191, China
4
Key Laboratory of Reproductive Health, National Health and Family Planning Commission of the People’s Republic of China, No. 38, Xueyuan Road, Haidian District, Beijing 100191, China
*
Author to whom correspondence should be addressed.
Int. J. Environ. Res. Public Health 2022, 19(23), 16010; https://doi.org/10.3390/ijerph192316010
Submission received: 24 September 2022 / Revised: 26 November 2022 / Accepted: 28 November 2022 / Published: 30 November 2022

Abstract

:
Although many studies of long COVID-19 were reported, there was a lack of systematic research which assessed the differences of long COVID-19 in regard to what unique SARS-CoV-2 strains caused it. As such, this systematic review and meta-analysis aims to evaluate the characteristics of long COVID-19 that is caused by different SARS-CoV-2 strains. We systematically searched the PubMed, EMBASE, and ScienceDirect databases in order to find cohort studies of long COVID-19 as defined by the WHO (Geneva, Switzerland). The main outcomes were in determining the percentages of long COVID-19 among patients who were infected with different SARS-CoV-2 strains. Further, this study was registered in PROSPERO (CRD42022339964). A total of 51 studies with 33,573 patients was included, of which three studies possessed the Alpha and Delta variants, and five studies possessed the Omicron variant. The highest pooled estimate of long COVID-19 was found in the CT abnormalities (60.5%; 95% CI: 40.4%, 80.6%) for the wild-type strain; fatigue (66.1%; 95% CI: 42.2%, 89.9%) for the Alpha variant; and ≥1 general symptoms (28.4%; 95% CI: 7.9%, 49.0%) for the Omicron variant. The pooled estimates of ≥1 general symptoms (65.8%; 95% CI: 47.7%, 83.9%) and fatigue were the highest symptoms found among patients infected with the Alpha variant, followed by the wild-type strain, and then the Omicron variant. The pooled estimate of myalgia was highest among patients infected with the Omicron variant (11.7%; 95%: 8.3%, 15.1%), compared with those infected with the wild-type strain (9.4%; 95%: 6.3%, 12.5%). The pooled estimate of sleep difficulty was lowest among the patients infected with the Delta variant (2.5%; 95%: 0.2%, 4.9%) when compared with those infected with the wild-type strain (24.5%; 95%: 17.5%, 31.5%) and the Omicron variant (18.7%; 95%: 1.0%, 36.5%). The findings of this study suggest that there is no significant difference between long COVID-19 that has been caused by different strains, except in certain general symptoms (i.e., in the Alpha or Omicron variant) and in sleep difficulty (i.e., the wild-type strain). In the context of the ongoing COVID-19 pandemic and its emerging variants, directing more attention to long COVID-19 that is caused by unique strains, as well as implementing targeted intervention measures to address it are vital.

1. Introduction

As of 25 August 2022, a total of 596,119,505 confirmed cases and 6,457,101 deaths due to the coronavirus disease (COVID-19) have placed a huge disease burden, as well as delivered an economic loss, on the world [1]. It has now been more than two years since the COVID-19 pandemic was officially declared by the World Health Organization (WHO) on 11 March 2020. Further, more studies have now begun to direct attention to the long-term impact of COVID-19. Scientific questions on the long-term impact of COVID-19, specifically on matters such as the diagnosis, as well as in its definition, still require more research [2]. COVID-19 may have detrimental sequelae even after the post-acute phase, thereby depicting a new pathological condition: the “post-COVID-19 syndrome (PCS)” or “long COVID-19” [3]. Long COVID-19, also called post COVID-19 condition, was defined as a condition that occurs in individuals with a history of probable or confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The condition is usually 3 months from the onset of COVID-19 that incurred the symptoms, lasted for at least 2 months, and cannot be explained by an alternative diagnosis [4]. Except in cases of systemic symptoms, existing evidence has shown that long COVID-19 can also involve multiple systems, including the mental, nervous, respiratory, cardiovascular, digestive systems, etc. [5,6,7,8,9].
In the early stages of the pandemic, previous studies reported long COVID-19 that was caused by the wild-type strain. Further, a meta-analysis reported that the common symptoms of long COVID-19 caused by the wild-type strain were fatigue or muscle weakness, as well as mild dyspnea [10]. Since the beginning of the COVID-19 epidemic, SARS-CoV-2 has evolved, mutated, and produced variants with variance in transmissibility and virulence. The SARS-CoV-2 variants emerged from the original wild-type strain, which includes: Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), and Omicron (B.1.1.529) [11]. These variants quickly became the main virus variants worldwide due to their increased transmissibility and virulence, a resistance to vaccine or acquired immunity from previous infection, and the ability to elude diagnostic detection [12].
Previous studies also reported on the differences in severity of COVID-19 cases via the different strains [13,14]. With the ongoing nature of COVID-19 and its emerging variants, the long COVID-19 of patients by unique variants should also be studied in order to avoid an excessive disease burden in the future. There have been a few studies that have reported on long COVID-19 during the different epidemic periods with the unique strains, but their results were consistent [15,16]. At present, there is no meta-analysis that has been conducted in order to provide evidence on the characteristics of long COVID-19 caused by the different strains. Thus, in this review, we aimed to systematically assess long COVID-19 that was caused by different SARS-CoV-2 strains at 3 months and above using the available evidence. This was performed so as to help better prepare management strategies and to better decease the long-term effects on infected people.

2. Methods

2.1. Search Strategy and Selection Criteria

The systematic literature review was reported in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist 2020. This review was also registered in PROSPERO (CRD42022339964).
We searched the PubMed, EMBASE, and ScienceDirect databases for studies without language restrictions, published up through 20 July 2022 with the following search terms: ((post COVID-19) OR (long COVID-19) OR ((COVID-19 OR SARS-CoV-2 OR coronavirus) AND ((long-term effect) OR sequelae OR (post condition) OR (post syndrome) OR (long-term consequence)))) AND (cohort OR (follow up) OR (case control study)). The initial searches were carried out by two investigators (MYR and DJ) independently.
The following PICO model was used to evaluate the study eligibility:
(P)
Participants: the long COVID-19 patients;
(I)
Intervention: the different SARS-CoV-2 strains;
(C)
Comparison: not applicable;
(O)
Outcome measures: the long COVID-19 effects and related issues, including clinical features (general symptoms, respiratory symptoms, cardiovascular symptoms, gastrointestinal symptoms, neurological, and psychiatric symptoms), pulmonary functional test (PFT), chest computerized tomography (CT]), and quality of life.

2.2. Inclusion and Exclusion Criteria

The inclusion criteria for selecting the cohort studies with reported confirmed dates or admissions, as well as the date or specific variants of long COVID-19 patients at 3 months and above were included. The following studies were excluded: (1) irrelevant to the subject of the meta-analysis, such as studies that did not use SARS-CoV-2 infection as the exposure; (2) insufficient data of long-term COVID-19 consequences; (3) duplicate studies or overlapping participants; (4) reviews, editorials, conference papers, case series/reports, secondary analysis, or animal experiments; and (5) qualitative designs. Studies were identified independently by two investigators (MYR and DJ) following the criteria above. This was achieved while discrepancies were solved by consensus or with a third investigator (DM).

2.3. Variants Identification and Data Extraction

In this study, we included studies which reported long COVID-19 that was caused by the wild-type strain and selected variants including the Alpha, Beta, Delta, Gamma, and Omicron strains (as defined in the terms of the WHO definitions [11]). If studies did not report specific strains, we then searched the genomic epidemiology of SARS-CoV-2 through the Global Initiative of Sharing All Influenza Data (GISAID) platform in order to find the main epidemic strain based on the period of the confirmed date or the admission date and country [17]. The results of the searches were screened in two stages. First, titles and abstracts were screened and, then, only were the relevant articles retained. Next, articles were read in detail—studies were selected for meta-analysis if they reported either results fitting our primary parameters (with CIs) or possessed sufficient information to facilitate the calculation of those values. The following data were extracted from the selected studies: (1) The basic information of the studies, including the first author, publication time, and country where the study was conducted; (2) the characteristics of the study population (including reported confirmed date or admission dates) or the specific strains of long COVID-19, as well as the sample size and follow-up period; (3) the clinical features of long COVID-19, including the number of cases with general long COVID-19 symptoms, i.e., respiratory symptoms, cardiovascular symptoms, gastrointestinal symptoms, neurological symptoms, and psychiatric symptoms, as well as the results of a PFT and CT; (4) the number of cases with problems in the five dimensions of the European Quality of Life Five-Dimension Five-Level Scale (EQ-5D-5L)—which is an instrument that was developed, by the EuroQol Group in 1987, for the purposes of describing and valuing health-related quality of life matters [18]. The data extraction and determination of information eligibility were independently conducted by the two investigators (MYR and DJ) following the criteria above, while discrepancies were solved by consensus or with a third investigator (DM).

2.4. Quality Assessment and Risk of Bias

We used the Newcastle–Ottawa quality assessment scale in order to evaluate the risk of bias in the included studies. The cohort studies were classified as having a low (≥7 stars), moderate (5–6 stars), or high risk of bias (≤4 stars), with an overall quality score of 9 stars. Quality assessment was independently conducted by two investigators (MYR and DJ), while discrepancies were solved by consensus or with a third investigator (DM).

2.5. Statistical Analysis

The Der Simonian and Laird method was performed in order to pool the prevalence (PP), as well as the 95% confidence interval (CI) of long COVID-19 at 3 months and above. Considering the fact that the heterogeneity was larger than 50% between the studies, random-effects models [19] were used in order to calculate the pooled effect and its 95% confidence interval (CI). In addition, publication bias was assessed by the Egger regression test [20]. After extracting all essential data using Excel 2021 (Microsoft Corporation), the data analyses were completed by using Stata 16.0. Moreover, two-sided p < 0.05 indicated statistical significance.

3. Results

3.1. Basic Characteristics

We identified 4710 records through PubMed, EMBASE, and ScienceDirect database searches. A total of 51 articles (i.e., 33,573 patients) were selected for analysis based on the inclusion and exclusion criteria [6,15,16,18,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67]. The study selection process was documented in Figure 1. Over the 51 studies, the quality assessment—which was conducted in order to evaluate the risk of bias—for 45 of the studies and the 6 remaining found the quality to be low and moderate, respectively. Most were conducted in Spain (9), followed by Italy (7), and then China (6). A total of 38 studies only included patients infected with the wild-type strain, three with the Alpha variant, three with the Delta variant, and five with the Omicron variant. The other two were the Beta and Gamma variants (Supplementary-Table S1).

3.2. Pooled Estimates of Long COVID-19

We included general symptoms; respiratory symptoms; cardiovascular symptoms; gastrointestinal symptoms; neurological and psychiatric symptoms; PFT; CT results; and quality of life evaluation. The top five symptoms with high pooled estimates were CT abnormalities (60.5%; 95% CI: 40.4%, 80.6%;); carbon monoxide diffusing capacity (DLCO) <80% (56.9%; 95% CI: 40.6%, 73.1%); ≥1 respiratory symptoms (51.1%; 95% CI: 41.4%, 60.8%); modified medical research council dyspnea scale (mMRC) = 0 (50.6%, 95% CI: 28.0%, 73.2%); and pain or discomfort (48.6%, 95% CI: 35.4%, 61.7%). In addition, there were 30 pooled estimates that were more than 10.0% in symptoms such as fatigue, cough, sleep difficulty, etc. The pooled estimates of the other symptoms, as well as the publication bias assessment via the Egger regression test are detailed in Supplementary-Table S2.

3.3. Pooled Estimates of Long COVID-19 by Different Strains

In regard to the wild-type strain, the highest pooled estimate of long COVID-19 was found in CT abnormalities (60.5%; 95% CI: 40.4%, 80.6%) for 11 of the studies. In regard to the Alpha variant, the pooled estimates of ≥1 general symptoms, fatigue, cough and dyspnea were 65.8% (95% CI: 47.7%, 83.9%) for three studies, 66.1% (95% CI: 42.2%, 89.9%) for three studies, 34.2% (95% CI: 8.3%, 60.1%) for two studies, and 23.7% (95% CI: 2.0%, 45.5%) for two studies. Two studies with the Delta variant only gave the pooled estimates of sleep difficulty (2.5%; 95% CI: 0.2%, 4.9%). In regard to the Omicron variant, the top three estimates were ≥1 symptoms (931/4860; 28.4%; 95% CI: 7.9%, 49.0%), sleep difficulty (3082/16211; 18.7%; 95% CI: 1.0%, 36.5%), and fatigue (3457/15848; 18.1%; 95% CI: 0.4%, 35.8%). The specific results are shown in Table 1.
As shown in Table 1, the pooled estimates of ≥1 general symptoms and fatigue were highest among the patients infected with the Alpha variant, followed by the wild-type strain and the Omicron variant. The pooled estimate of myalgia was higher among patients infected with the Omicron variant (11.7%; 95%: 8.3%, 15.1%), compared with patients infected with the wild-type strain (9.4%; 95%: 6.3%, 12.5%). The pooled estimate of sleep difficulty was lowest among patients infected with the Delta variant (2.5%; 95%: 0.2%, 4.9%), compared with patients infected with the wild-type strain (24.5%; 95%: 17.5%, 31.5%) and the Omicron variant (18.7%; 95%: 1.0%, 36.5%).

4. Discussion

The emerging unique variants of SARS-CoV-2 indicate that long COVID-19 may be different due to changes in virulence between the variants. This systematic review and meta-analysis comprehensively assessed the long COVID-19 caused by different SARS-CoV-2 strains in order to supplement limited evidence. Generally, this study reported the most common long COVID-19 and its differences between the unique strains. Our findings showed that CT abnormalities (60.5%), carbon monoxide diffusing capacity <80% (56.9%), and ≥1 respiratory symptoms (51.1%) were common sequelae among COVID-19 patients, which are similar results to our previous study [10]. Groff et al. also reported that the most prevalent pulmonary sequelae was found in chest imaging abnormality (62.2%, 95%CI: 45.8–76.5%) [68]. Furthermore, SARS-CoV-2 infection generally causes direct and indirect injury of the pulmonary system by invasion and via a cytokine storm [69,70,71]. Our results indicated that the damage to the respiratory symptoms caused by SARS-CoV-2 may be prolonged. Therefore, a consideration on the persistent rehabilitation treatment that will be utilized is vital.
Importantly, our study first found, using meta-analysis, that long COVID-19 may be different according to what strain caused it. The Alpha variant was first reported in the United Kingdom in September 2020. Then, the Delta variant was reported in India in October 2020. Finally, the Omicron variant was reported in multiple countries in November 2021 [11]. In regard to the Delta variant, its infected wave was attributed to the epidemic across 98 countries in 2021, such as India, the UK, the US, and certain Southeast Asian countries [13]. According to the WHO report—as of epidemiological week 35—a total of 48 countries have reported detection of Omicron [72]. In respect of considering the rehabilitation of patients by the different strains in the future, understanding the differences of sequelae is crucial. Duong et al. reported that the Omicron variant was around one to three times the daily number of cases of hospitalization that is incurred in comparison with the Delta variant [13]. The Omicron variant has high transmissibility and severity. As such, the sequelae caused by it should not be ignored. Moreover, we found that the pooled estimate of sleep difficulty was low among patients infected with the Delta variant, but was high among patients infected with the wild-type strain and the Omicron variant. Meanwhile, the pooled estimate of myalgia was higher among patients infected with the Omicron variant, compared with patients infected with the wild-type strain. However, we found that the pooled estimates of ≥1 general symptoms and fatigue were more than sixty percent among patients infected with the Alpha variant, which was higher than those infected with the wild-type strain and the Omicron variant.
Close attention should be paid to the fact that vaccination may have had influences on our results. Duong et al. reported that the Omicron variant had less effect on the number of daily intensive care unit (ICU) cases, most likely due to the total number of vaccinated people in each country [13]. Yu et al. also found that the pooled proportion of asymptomatic infection and non-severe disease with Omicron were 25.5% and 97.9%, respectively, which is significantly higher than those of Delta with 8.4% and 91.4% [14]. The vaccination of a booster dose that may cause variants had less effect on the severity of COVID-19 or long COVID-19 when compared with the epidemic of the wild-type strain or the Alpha variant [73,74,75,76].
There is currently a lack of cohort studies that can be utilized to evaluate the CT and PFT results of long COVID-19 caused by unique variants. Thus, more research studies are needed. This study provided a part of the evidence that is needed for a full meta-analysis of long COVID-19 via its different strains.
Our study also possessed certain limitations. Although the identification of strains was based on the largest genomic epidemiology of the SARS-CoV-2 platform, GISAID, it is possible to have misclassified strains [17]. Therefore, our results should be interpreted with caution. Secondly, the incidence and evolution of long COVID-19 are dependent on complicated factors, including vaccination status and geographic region [68]. Due to the fact that the studies with variants that were possible to be included were limited, we could not, thus, analyze the effect of other factors on our results.

5. Conclusions

Although variants such as the Alpha variant are currently only prevalent in a few countries, the Delta and Omicron variants have become the dominant strains in many countries around the world [77]. Identifying the long COVID-19 of different strains is a key factor in designing an appropriate health management strategy. We found that the pooled estimates of ≥1 general symptoms and fatigue were more than sixty percent among patients infected with the Alpha variant, which was higher than those infected with the wild-type strain and the Omicron variant. Meanwhile, the pooled estimate of myalgia was higher among patients infected with the Omicron variant, compared with patients infected with the wild-type strain. The pooled estimate of sleep difficulty was low among patients infected with the Delta variant, but it was high among patients infected with the wild-type strain and the Omicron variant. In conclusion, our findings suggest that different strains could all cause long COVID-19. Furthermore, long COVID-19 that is caused by different strains has no differences, except in certain symptoms (including general symptoms and sleep difficulty that were found to be discrepant between the unique strains). In regard to the ongoing COVID-19 pandemic and its emerging variants, more attention needs to be directed to instances of long COVID-19 that are caused by unique strains. Furthermore, implementing targeted intervention measures to address them are vital.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/ijerph192316010/s1. Table S1: Included Studies. Table S2: Pooled prevalence of COVID-19 consequences at follow-up 3 months and above.

Author Contributions

M.D., M.L., and J.L. conceptualized and designed the study; M.D., Y.M. and J.D. conducted the data acquisition; M.D. performed the data curation, formal analysis, visualization and writing—original draft, J.L. completed the writing—reviewing and editing. All authors have read and agreed to the published version of the manuscript.

Funding

This work was partly supported by the National Natural Science Foundation of China (72122001, 71934002); the Beijing Natural Science Foundation-Haidian Original Innovation Joint Fund (L222027); the National Key Research and Development Project of China (2021ZD0114101, 2021ZD0114104, 2021ZD0114105); the National Statistical Science Research Project (2021LY038); the Fundamental Research Funds for the Central Universities that is supported by the Global Center for Infectious Disease and Policy Research & Global Health and Infectious Diseases Group, of Peking University (202204); and the National Science and Technology Project on Development Assistance for Technology, Developing China-ASEAN Public Health Research and Development Collaborating Center (KY202101004).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data are available from the corresponding authors on request.

Conflicts of Interest

The authors declare no conflict of interest.

Abbreviations

COVID-19Coronavirus disease 2019
WHOWorld Health Organization
SARS-CoV-2Severe acute respiratory syndrome coronavirus 2
GISAIDGlobal Initiative of Sharing All Influenza Data
PRISMAPreferred reporting items for systematic reviews and meta-analyses
PFTPulmonary functional test
CTComputerized tomography
EQ-5D-5L European Quality of Life Five-Dimension Five-Level Scale
PPPooled prevalence
CIConfidence interval
DLCOCarbon monoxide diffusing capacity
mMRCModified medical research council dyspnea scale
ICUIntensive care unit

References

  1. WHO. Coronavirus (COVID-19) Dashboard. Available online: https://covid19.who.int/ (accessed on 18 May 2022).
  2. The, L. Facing up to long COVID. Lancet (Lond. Engl.) 2020, 396, 1861. [Google Scholar] [CrossRef]
  3. De Sire, A.; Moggio, L.; Marotta, N.; Agostini, F.; Tasselli, A.; Drago Ferrante, V.; Curci, C.; Calafiore, D.; Ferraro, F.; Bernetti, A.; et al. Impact of Rehabilitation on Fatigue in Post-COVID-19 Patients: A Systematic Review and Meta-Analysis. Appl. Sci. 2022, 12, 8593. [Google Scholar] [CrossRef]
  4. A Clinical Case Definition of Post COVID-19 Condition by a Delphi Consensus, 6 October 2021. Available online: https://www.who.int/publications/i/item/WHO-2019-nCoV-Post_COVID-19_condition-Clinical_case_definition-2021.1 (accessed on 22 April 2022).
  5. Logue, J.K.; Franko, N.M.; McCulloch, D.J.; McDonald, D.; Magedson, A.; Wolf, C.R.; Chu, H.Y. Sequelae in Adults at 6 Months After COVID-19 Infection. JAMA Netw. Open 2021, 4, e210830. [Google Scholar] [CrossRef]
  6. Sigfrid, L.; Drake, T.M.; Pauley, E.; Jesudason, E.C.; Olliaro, P.; Lim, W.S.; Gillesen, A.; Berry, C.; Lowe, D.J.; McPeake, J.; et al. Long Covid in adults discharged from UK hospitals after Covid-19: A prospective, multicentre cohort study using the ISARIC WHO Clinical Characterisation Protocol. Lancet Reg. Health—Eur. 2021, 8, 100186. [Google Scholar] [CrossRef] [PubMed]
  7. Huang, C.; Huang, L.; Wang, Y.; Li, X.; Ren, L.; Gu, X.; Kang, L.; Guo, L.; Liu, M.; Zhou, X.; et al. 6-month consequences of COVID-19 in patients discharged from hospital: A cohort study. Lancet 2021, 397, 220–232. [Google Scholar] [CrossRef] [PubMed]
  8. Huang, L.; Li, X.; Gu, X.; Zhang, H.; Ren, L.; Guo, L.; Liu, M.; Wang, Y.; Cui, D.; Wang, Y.; et al. Health outcomes in people 2 years after surviving hospitalisation with COVID-19: A longitudinal cohort study. Lancet. Respir. Med. 2022, 10, 863–876. [Google Scholar] [CrossRef]
  9. Cohen, K.; Ren, S.; Heath, K.; Dasmariñas, M.C.; Jubilo, K.G.; Guo, Y.; Lipsitch, M.; Daugherty, S.E. Risk of persistent and new clinical sequelae among adults aged 65 years and older during the post-acute phase of SARS-CoV-2 infection: Retrospective cohort study. BMJ 2022, 376, e068414. [Google Scholar] [CrossRef]
  10. Ma, Y.; Deng, J.; Liu, Q.; Du, M.; Liu, M.; Liu, J. Long-Term Consequences of COVID-19 at 6 Months and Above: A Systematic Review and Meta-Analysis. Int. J. Environ. Res. Public Health 2022, 19, 6865. [Google Scholar] [CrossRef]
  11. World Health Organization. Tracking SARS-CoV-2 Variants. Available online: https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/ (accessed on 17 April 2022).
  12. US Centers for Disease Control and Prevention. SARS-CoV-2 Variant Classifications and Definitions. Available online: https://www.cdc.gov/coronavirus/2019-ncov/variants (accessed on 27 November 2022).
  13. Duong, B.V.; Larpruenrudee, P.; Fang, T.; Hossain, S.I.; Saha, S.C.; Gu, Y.; Islam, M.S. Is the SARS CoV-2 Omicron Variant Deadlier and More Transmissible Than Delta Variant? Int. J. Environ. Res. Public Health 2022, 19, 4586. [Google Scholar] [CrossRef]
  14. Yu, W.; Guo, Y.; Zhang, S.; Kong, Y.; Shen, Z.; Zhang, J. Proportion of asymptomatic infection and nonsevere disease caused by SARS-CoV-2 Omicron variant: A systematic review and analysis. J. Med. Virol. 2022, 94, 5790–5801. [Google Scholar] [CrossRef]
  15. Emecen, A.N.; Keskin, S.; Turunc, O.; Suner, A.F.; Siyve, N.; Basoglu Sensoy, E.; Dinc, F.; Kilinc, O.; Avkan Oguz, V.; Bayrak, S.; et al. The presence of symptoms within 6 months after COVID-19: A single-center longitudinal study. Ir. J. Med. Sci. 2022, 10.1007/s11845-022-03072-0. [Google Scholar] [CrossRef] [PubMed]
  16. Peter, R.S.; Nieters, A.; Kräusslich, H.G.; Brockmann, S.O.; Göpel, S.; Kindle, G.; Merle, U.; Steinacker, J.M.; Rothenbacher, D.; Kern, W.V.; et al. Prevalence, determinants, and impact on general health and working capacity of post-acute sequelae of COVID-19 six to 12 months after infection: A population-based retrospective cohort study from southern Germany. medRxiv 2022. [Google Scholar] [CrossRef]
  17. Global Initiative of Sharing All Influenza Data (GISAID) Platform. Genomic Epidemiology of SARS-CoV-2 with Subsampling Focused Globally over the Past 6 Months. Available online: https://gisaid.org/phylodynamics/global/nextstrain/ (accessed on 10 September 2022).
  18. Todt, B.C.; Szlejf, C.; Duim, E.; Linhares, A.O.M.; Kogiso, D.; Varela, G.; Campos, B.A.; Baghelli Fonseca, C.M.; Polesso, L.E.; Bordon, I.N.S.; et al. Clinical outcomes and quality of life of COVID-19 survivors: A follow-up of 3 months post hospital discharge. Respir. Med. 2021, 184, 106453. [Google Scholar] [CrossRef] [PubMed]
  19. DerSimonian, R.; Laird, N. Meta-analysis in clinical trials revisited. Contemp. Clin. Trials 2015, 45, 139–145. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  20. Egger, M.; Davey Smith, G.; Schneider, M.; Minder, C. Bias in meta-analysis detected by a simple, graphical test. BMJ (Clin. Res. Ed.) 1997, 315, 629–634. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  21. Och, A.; Tylicki, P.; Polewska, K.; Puchalska-Reglińska, E.; Parczewska, A.; Szabat, K.; Biedunkiewicz, B.; Dębska-ślizień, A.; Tylicki, L. Persistent post-covid-19 syndrome in hemodialyzed patients—A longitudinal cohort study from the North of Poland. J. Clin. Med. 2021, 10, 4451. [Google Scholar] [CrossRef]
  22. Lindahl, A.; Aro, M.; Reijula, J.; Mäkelä, M.J.; Ollgren, J.; Puolanne, M.; Järvinen, A.; Vasankari, T. Women report more symptoms and impaired quality of life: A survey of Finnish COVID-19 survivors. Infect. Dis. 2022, 54, 53–62. [Google Scholar] [CrossRef]
  23. Becker, C.; Beck, K.; Zumbrunn, S.; Memma, V.; Herzog, N.; Bissmann, B.; Gross, S.; Loretz, N.; Mueller, J.; Amacher, S.A.; et al. Long COVID 1 year after hospitalisation for COVID-19: A prospective bicentric cohort study. Swiss Med. Wkly. 2021, 151, w30091. [Google Scholar] [CrossRef]
  24. Dai, S.; Zhao, B.; Liu, D.; Zhou, Y.; Liu, Y.; Lan, L.; Li, Y.; Luo, W.; Zeng, Y.; Li, W. Follow-up study of the cardiopulmonary and psychological outcomes of covid-19 survivors six months after discharge in sichuan, china. Int. J. Gen. Med. 2021, 14, 7207–7217. [Google Scholar] [CrossRef]
  25. Caruso, D.; Guido, G.; Zerunian, M.; Polidori, T.; Lucertini, E.; Pucciarelli, F.; Polici, M.; Rucci, C.; Bracci, B.; Nicolai, M.; et al. Post-acute sequelae of COVID-19 pneumonia: Six-month chest CT follow-up. Radiology 2021, 301, E36–E405. [Google Scholar] [CrossRef]
  26. Bretas, D.C.; Leite, A.S.; Mancuzo, E.V.; Prata, T.A.; Andrade, B.H.; Oliveira, J.D.G.F.; Batista, A.P.; Machado-Coelho, G.L.L.; Augusto, V.M.; Marinho, C.C. Lung function six months after severe COVID-19: Does time, in fact, heal all wounds? Braz. J. Infect. Dis. 2022, 26, 102352. [Google Scholar] [CrossRef] [PubMed]
  27. Noviello, D.; Costantino, A.; Muscatello, A.; Bandera, A.; Consonni, D.; Vecchi, M.; Basilisco, G. Functional Gastrointestinal And Somatoform Symptoms Five Months After SARS-CoV-2 Infection: A Controlled Cohort Study. Dig. Liver Dis. 2021, 53, S119–S120. [Google Scholar] [CrossRef]
  28. Buonsenso, D.; Munblit, D.; Pazukhina, E.; Ricchiuto, A.; Sinatti, D.; Zona, M.; De Matteis, A.; D’Ilario, F.; Gentili, C.; Lanni, R.; et al. Post-COVID Condition in Adults and Children Living in the Same Household in Italy: A Prospective Cohort Study Using the ISARIC Global Follow-Up Protocol. Front. Pediatr. 2022, 10, 834875. [Google Scholar] [CrossRef] [PubMed]
  29. Zuschlag, D.; Grandt, D.; Custodis, F.; Braun, C.; Häuser, W. Spontaneously reported persistent symptoms related to coronavirus disease 2019 one year after hospital discharge: A retrospective cohort single-center study. Schmerz 2022, 36, 315–325. [Google Scholar] [CrossRef] [PubMed]
  30. Menges, D.; Ballouz, T.; Anagnostopoulos, A.; Aschmann, H.E.; Domenghino, A.; Fehr, J.S.; Puhan, M.A. Burden of post-COVID-19 syndrome and implications for healthcare service planning: A population-based cohort study. PLoS ONE 2021, 16, e0254523. [Google Scholar] [CrossRef]
  31. Tessitore, E.; Handgraaf, S.; Poncet, A.; Achard, M.; Höfer, S.; Carballo, S.; Marti, C.; Follonier, C.; Girardin, F.; Mach, F.; et al. Symptoms and quality of life at 1-year follow up of patients discharged after an acute COVID-19 episode. Swiss Med. Wkly. 2021, 151, W30093. [Google Scholar] [CrossRef]
  32. Zhou, F.; Tao, M.; Shang, L.; Liu, Y.; Pan, G.; Jin, Y.; Wang, L.; Hu, S.; Li, J.; Zhang, M.; et al. Assessment of Sequelae of COVID-19 Nearly 1 Year After Diagnosis. Front. Med. 2021, 8, 717194. [Google Scholar] [CrossRef]
  33. Desgranges, F.; Tadini, E.; Munting, A.; Regina, J.; Filippidis, P.; Viala, B.; Karachalias, E.; Suttels, V.; Haefliger, D.; Kampouri, E.; et al. Post-COVID-19 Syndrome in Outpatients: A Cohort Study. J. Gen. Intern. Med. 2022, 37, 1943–1952. [Google Scholar] [CrossRef]
  34. Förster, C.; Colombo, M.G.; Wetzel, A.J.; Martus, P.; Joos, S. Persisting Symptoms after COVID-19: Prevalence and Risk Factors in a Population-Based Cohort. Dtsch. Arztebl. Int. 2022, 119, 167–174. [Google Scholar] [CrossRef]
  35. Nesan, G.S.C.Q.; Keerthana, D.; Yamini, R.; Jain, T.; Kumar, D.; Eashwer, A.; Maiya, G.R. 3-Month Symptom-Based Ambidirectional Follow-up Study Among Recovered COVID-19 Patients from a Tertiary Care Hospital Using Telehealth in Chennai, India. Inq. A J. Med. Care Organ. Provis. Financ. 2021, 58, 469580211060165. [Google Scholar] [CrossRef]
  36. Prestes, G.D.S.; Simon, C.S.; Walz, R.; Ritter, C.; Dal-Pizzol, F. Respiratory Outcomes After 6 Months of Hospital Discharge in Patients Affected by COVID-19: A Prospective Cohort. Front. Med. 2022, 9, 795074. [Google Scholar] [CrossRef]
  37. Calcaianu, G.; Degoul, S.; Michau, B.; Payen, T.; Gschwend, A.; Fore, M.; Iamandi, C.; Morel, H.; Oster, J.-P.; Bizieux, A.; et al. Mid-term pulmonary sequelae after hospitalisation for COVID-19: The French SISCOVID cohort. Respir. Med. Res. 2022, 82, 100933. [Google Scholar] [CrossRef] [PubMed]
  38. Vargas Centanaro, G.; Calle Rubio, M.; Álvarez-Sala Walther, J.L.; Martinez-Sagasti, F.; Albuja Hidalgo, A.; Herranz Hernández, R.; Rodríguez Hermosa, J.L. Long-term Outcomes and Recovery of Patients who Survived COVID-19: LUNG INJURY COVID-19 Study. Open Forum Infect. Dis. 2022, 9, ofac098. [Google Scholar] [CrossRef] [PubMed]
  39. Labarca, G.; Henríquez-Beltrán, M.; Lastra, J.; Enos, D.; Llerena, F.; Cigarroa, I.; Lamperti, L.; Ormazabal, V.; Ramirez, C.; Espejo, E.; et al. Analysis of clinical symptoms, radiological changes and pulmonary function data 4 months after COVID-19. Clin. Respir. J. 2021, 15, 992–1002. [Google Scholar] [CrossRef] [PubMed]
  40. Klein, H.; Asseo, K.; Karni, N.; Benjamini, Y.; Nir-Paz, R.; Muszkat, M.; Israel, S.; Niv, M.Y. Onset, duration and unresolved symptoms, including smell and taste changes, in mild COVID-19 infection: A cohort study in Israeli patients. Clin. Microbiol. Infect. 2021, 27, 769–774. [Google Scholar] [CrossRef]
  41. Martin-Loeches, I.; Motos, A.; Menéndez, R.; Gabarrús, A.; González, J.; Fernández-Barat, L.; Ceccato, A.; Pérez-Arnal, R.; García-Gasulla, D.; Ferrer, R.; et al. ICU-Acquired Pneumonia Is Associated with Poor Health Post-COVID-19 Syndrome. J. Clin. Med. 2022, 11, 224. [Google Scholar] [CrossRef]
  42. González, J.; Benítez, I.D.; Carmona, P.; Santisteve, S.; Monge, A.; Moncusí-Moix, A.; Gort-Paniello, C.; Pinilla, L.; Carratalá, A.; Zuil, M.; et al. Pulmonary Function and Radiologic Features in Survivors of Critical COVID-19: A 3-Month Prospective Cohort. Chest 2021, 160, 187–198. [Google Scholar] [CrossRef]
  43. Aranda, J.; Oriol, I.; Martín, M.; Feria, L.; Vázquez, N.; Rhyman, N.; Vall-Llosera, E.; Pallarés, N.; Coloma, A.; Pestaña, M.; et al. Long-term impact of COVID-19 associated acute respiratory distress syndrome. J. Infect. 2021, 83, 581–588. [Google Scholar] [CrossRef]
  44. Zhang, J.; Shu, T.; Zhu, R.; Yang, F.; Zhang, B.; Lai, X. The Long-Term Effect of COVID-19 Disease Severity on Risk of Diabetes Incidence and the Near 1-Year Follow-Up Outcomes among Postdischarge Patients in Wuhan. J. Clin. Med. 2022, 11, 3094. [Google Scholar] [CrossRef]
  45. Kingery, J.R.; Safford, M.M.; Martin, P.; Lau, J.D.; Rajan, M.; Wehmeyer, G.T.; Li, H.A.; Alshak, M.N.; Jabri, A.; Kofman, A.; et al. Health Status, Persistent Symptoms, and Effort Intolerance One Year After Acute COVID-19 Infection. J. Gen. Intern. Med. 2022, 37, 1218–1225. [Google Scholar] [CrossRef]
  46. Zhan, K.; Zhang, X.; Wang, B.; Jiang, Z.; Fang, X.; Yang, S.; Jia, H.; Li, L.; Cao, G.; Zhang, K.; et al. Short-and long-term prognosis of glycemic control in COVID-19 patients with type 2 diabetes. QJM 2022, 115, 131–139. [Google Scholar] [CrossRef] [PubMed]
  47. Miskowiak, K.W.; Fugledalen, L.; Jespersen, A.E.; Sattler, S.M.; Podlekareva, D.; Rungby, J.; Porsberg, C.M.; Johnsen, S. Trajectory of cognitive impairments over 1 year after COVID-19 hospitalisation: Pattern, severity, and functional implications. Eur. Neuropsychopharmacol. 2022, 59, 82–92. [Google Scholar] [CrossRef] [PubMed]
  48. Peghin, M.; Palese, A.; Venturini, M.; De Martino, M.; Gerussi, V.; Graziano, E.; Bontempo, G.; Marrella, F.; Tommasini, A.; Fabris, M.; et al. Post-COVID-19 symptoms 6 months after acute infection among hospitalized and non-hospitalized patients. Clin. Microbiol. Infect. 2021, 27, 1507–1513. [Google Scholar] [CrossRef] [PubMed]
  49. Colizzi, M.; Peghin, M.; De Martino, M.; Bontempo, G.; Gerussi, V.; Palese, A.; Isola, M.; Tascini, C.; Balestrieri, M. Mental health symptoms one year after acute COVID-19 infection: Prevalence and risk factors. Rev. Psiquiatr. Salud Ment. 2022. [Google Scholar] [CrossRef] [PubMed]
  50. Vejen, M.; Hansen, E.F.; Al-Jarah, B.N.I.; Jensen, C.; Thaning, P.; Jeschke, K.N.; Ulrik, C.S. Hospital admission for COVID-19 pneumonitis—Long-term impairment in quality of life and lung function. Eur. Clin. Respir. J. 2022, 9, 2024735. [Google Scholar] [CrossRef] [PubMed]
  51. Aiello, M.; Marchi, L.; Calzetta, L.; Speroni, S.; Frizzelli, A.; Ghirardini, M.; Celiberti, V.; Sverzellati, N.; Majori, M.; Mori, P.A.; et al. Coronavirus Disease 2019: COSeSco—A Risk Assessment Score to Predict the Risk of Pulmonary Sequelae in COVID-19 Patients. Respiration 2021, 101, 272–280. [Google Scholar] [CrossRef] [PubMed]
  52. Rivera-Izquierdo, M.; Láinez-Ramos-Bossini, A.J.; de Alba, I.G.; Ortiz-González-Serna, R.; Serrano-Ortiz, Á.; Fernández-Martínez, N.F.; Ruiz-Montero, R.; Cervilla, J.A. Long COVID 12 months after discharge: Persistent symptoms in patients hospitalised due to COVID-19 and patients hospitalised due to other causes-a multicentre cohort study. BMC Med. 2022, 20, 92. [Google Scholar] [CrossRef]
  53. Rigoni, M.; Torri, E.; Nollo, G.; Donne, L.D.; Rizzardo, S.; Lenzi, L.; Falzone, A.; Cozzio, S. "Long COVID" results after hospitalization for SARS-CoV-2 infection. Sci. Rep. 2022, 12, 9581. [Google Scholar] [CrossRef]
  54. Mølhave, M.; Leth, S.; Gunst, J.D.; Jensen-Fangel, S.; Østergaard, L.; Wejse, C.; Agergaard, J. Long-term symptoms among hospitalized COVID-19 patients 48 weeks after discharge—A prospective cohort study. J. Clin. Med. 2021, 10, 5298. [Google Scholar] [CrossRef]
  55. Porto, M.H.; Delgado, T.; Aguirre-Jaime, A.; Ramos, M.J.; Campos, S.; Acosta, O.; Llanos, A.B.; Lecuona, M. Patients at risk of pulmonary fibrosis Post COVID-19: Epidemiology, pulmonary sequelaes and humoral response. medRxiv 2022. [Google Scholar] [CrossRef]
  56. Attauabi, M.; Dahlerup, J.F.; Poulsen, A.; Hansen, M.R.; Vester-Andersen, M.K.; Eraslan, S.; Prahm, A.P.; Pedersen, N.; Larsen, L.; Jess, T.; et al. Outcomes and Long-Term Effects of COVID-19 in Patients with Inflammatory Bowel Diseases—A Danish Prospective Population-Based Cohort Study with Individual-Level Data. J. Crohn’s Colitis 2022, 16, 757–767. [Google Scholar] [CrossRef] [PubMed]
  57. Hossain, M.A.; Hossain, K.M.A.; Saunders, K.; Uddin, Z.; Walton, L.M.; Raigangar, V.; Sakel, M.; Shafin, R.; Hossain, M.S.; Kabir, M.F.; et al. Prevalence of Long COVID symptoms in Bangladesh: A prospective Inception Cohort Study of COVID-19 survivors. BMJ Glob. Health 2021, 6, 006838. [Google Scholar] [CrossRef]
  58. Eloy, P.; Tardivon, C.; Martin-Blondel, G.; Isnard, M.; Turnier, P.L.; Marechal, M.L.; CabiÉ, A.; Launay, O.; Tattevin, P.; Senneville, E.; et al. Severity of self-reported symptoms and psychological burden 6-months after hospital admission for COVID-19: A prospective cohort study. Int. J. Infect. Dis. 2021, 112, 247–253. [Google Scholar] [CrossRef] [PubMed]
  59. Duggal, P.; Penson, T.; Manley, H.N.; Vergara, C.; Munday, R.M.; Duchen, D.; Linton, E.A.; Zurn, A.; Keruly, J.C.; Mehta, S.H.; et al. Post-sequelae symptoms and comorbidities after COVID-19. J. Med. Virol. 2022, 94, 2060–2066. [Google Scholar] [CrossRef] [PubMed]
  60. Mónica, R.-S.; Maribel, Q.-F.; Javier, J.; Isabel, L.-M.; Rocío, T.; Rocío, A.; Javier, G.-P.F. Cardiac complications in a geriatric population hospitalized with COVID-19: The OCTA-COVID cohort. Rev. Española Geriatría Gerontol. 2022, 57, 63–70. [Google Scholar] [CrossRef]
  61. Robey, R.C.; Kemp, K.; Hayton, P.; Mudawi, D.; Wang, R.; Greaves, M.; Yioe, V.; Rivera-Ortega, P.; Avram, C.; Chaudhuri, N. Pulmonary Sequelae at 4 Months After COVID-19 Infection: A Single-Centre Experience of a COVID Follow-Up Service. Adv. Ther. 2021, 38, 4505–4519. [Google Scholar] [CrossRef]
  62. Titze-de-Almeida, R.; da Cunha, T.R.; dos Santos Silva, L.D.; Ferreira, C.S.; Silva, C.P.; Ribeiro, A.P.; de Castro Moreira Santos Júnior, A.; de Paula Brandão, P.R.; Silva, A.P.B.; da Rocha, M.C.O.; et al. Persistent, new-onset symptoms and mental health complaints in Long COVID in a Brazilian cohort of non-hospitalized patients. BMC Infect. Dis. 2022, 22, 133. [Google Scholar] [CrossRef]
  63. Zayet, S.; Zahra, H.; Royer, P.Y.; Tipirdamaz, C.; Mercier, J.; Gendrin, V.; Lepiller, Q.; Marty-Quinternet, S.; Osman, M.; Belfeki, N.; et al. Post-COVID-19 Syndrome: Nine Months after SARS-CoV-2 Infection in a Cohort of 354 Patients: Data from the First Wave of COVID-19 in Nord Franche-Comté Hospital, France. Microorganisms 2021, 9, 1719. [Google Scholar] [CrossRef]
  64. Liao, X.; Li, D.; Liu, Z.; Ma, Z.; Zhang, L.; Dong, J.; Shi, Y.; Gu, X.; Zheng, G.; Huang, L.; et al. Pulmonary Sequelae in Patients After Recovery From Coronavirus Disease 2019: A Follow-Up Study With Chest CT. Front. Med. 2021, 8, 686878. [Google Scholar] [CrossRef]
  65. Li, Y.; Han, X.; Huang, J.; Alwalid, O.; Jia, X.; Yuan, M.; Cao, Y.; Shao, G.; Cui, Y.; Liu, J.; et al. Follow-up study of pulmonary sequelae in discharged COVID-19 patients with diabetes or secondary hyperglycemia. Eur. J. Radiol. 2021, 144, 109997. [Google Scholar] [CrossRef]
  66. Aparisi, Á.; Ybarra-Falcón, C.; García-Gómez, M.; Tobar, J.; Iglesias-Echeverría, C.; Jaurrieta-Largo, S.; Ladrón, R.; Uribarri, A.; Catalá, P.; Hinojosa, W.; et al. Exercise Ventilatory Inefficiency in Post-COVID-19 Syndrome: Insights from a Prospective Evaluation. J. Clin. Med. 2021, 10, 2591. [Google Scholar] [CrossRef]
  67. Romero-Duarte, Á.; Rivera-Izquierdo, M.; Guerrero-Fernández de Alba, I.; Pérez-Contreras, M.; Fernández-Martínez, N.F.; Ruiz-Montero, R.; Serrano-Ortiz, Á.; González-Serna, R.O.; Salcedo-Leal, I.; Jiménez-Mejías, E.; et al. Sequelae, persistent symptomatology and outcomes after COVID-19 hospitalization: The ANCOHVID multicentre 6-month follow-up study. BMC Med. 2021, 19, 129. [Google Scholar] [CrossRef] [PubMed]
  68. Groff, D.; Sun, A.; Ssentongo, A.E.; Ba, D.M.; Parsons, N.; Poudel, G.R.; Lekoubou, A.; Oh, J.S.; Ericson, J.E.; Ssentongo, P.; et al. Short-term and Long-term Rates of Postacute Sequelae of SARS-CoV-2 Infection: A Systematic Review. JAMA Netw. Open 2021, 4, 28568. [Google Scholar] [CrossRef] [PubMed]
  69. Hamming, I.; Timens, W.; Bulthuis, M.L.; Lely, A.T.; Navis, G.; van Goor, H. Tissue distribution of ACE2 protein, the functional receptor for SARS coronavirus. A first step in understanding SARS pathogenesis. J. Pathol. 2004, 203, 631–637. [Google Scholar] [CrossRef]
  70. Huang, C.; Wang, Y.; Li, X.; Ren, L.; Zhao, J.; Hu, Y.; Zhang, L.; Fan, G.; Xu, J.; Gu, X.; et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet (Lond. Engl.) 2020, 395, 497–506. [Google Scholar] [CrossRef] [Green Version]
  71. Mehta, P.; McAuley, D.F.; Brown, M.; Sanchez, E.; Tattersall, R.S.; Manson, J.J. COVID-19: Consider cytokine storm syndromes and immunosuppression. Lancet (Lond. Engl.) 2020, 395, 1033–1034. [Google Scholar] [CrossRef]
  72. Coronavirus Disease (COVID-19) Weekly Epidemiological Update and Weekly Operational Update. Available online: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/situation-reports (accessed on 24 September 2022).
  73. Kow, C.S.; Ramachandram, D.S.; Hasan, S.S. The effectiveness of mRNA-1273 vaccine against COVID-19 caused by Delta variant: A systematic review and meta-analysis. J. Med. Virol. 2022, 94, 2269–2274. [Google Scholar] [CrossRef]
  74. Külper-Schiek, W.; Piechotta, V.; Pilic, A.; Batke, M.; Dreveton, L.S.; Geurts, B.; Koch, J.; Köppe, S.; Treskova, M.; Vygen-Bonnet, S.; et al. Facing the Omicron variant-how well do vaccines protect against mild and severe COVID-19? Third interim analysis of a living systematic review. Front. Immunol. 2022, 13, 940562. [Google Scholar] [CrossRef]
  75. Al-Aly, Z.; Bowe, B.; Xie, Y. Long COVID after breakthrough SARS-CoV-2 infection. Nat. Med. 2022, 28, 1461–1467. [Google Scholar] [CrossRef]
  76. Peghin, M.; De Martino, M.; Palese, A.; Gerussi, V.; Bontempo, G.; Graziano, E.; Visintini, E.; D’Elia, D.; Dellai, F.; Marrella, F.; et al. Post-COVID-19 syndrome and humoral response association after 1 year in vaccinated and unvaccinated patients. Clin. Microbiol. Infect. Off. Publ. Eur. Soc. Clin. Microbiol. Infect. Dis. 2022, 28, 1140–1148. [Google Scholar] [CrossRef]
  77. Wu, Y.; Kang, L.; Guo, Z.; Liu, J.; Liu, M.; Liang, W. Incubation Period of COVID-19 Caused by Unique SARS-CoV-2 Strains: A Systematic Review and Meta-analysis. JAMA Netw. Open 2022, 5, e2228008. [Google Scholar] [CrossRef] [PubMed]
Figure 1. Study flow diagram.
Figure 1. Study flow diagram.
Ijerph 19 16010 g001
Table 1. Pooled prevalence of long COVID-19 by different strains at 3 months follow-up and above.
Table 1. Pooled prevalence of long COVID-19 by different strains at 3 months follow-up and above.
ConsequencesNumber of StudiesPatients n/NPP (95% CI, %)p-ValueI2
General Symptoms
≥1 symptoms
Alpha3475/77965.8 (47.7, 83.9)<0.0596.8%
Delta156/16234.6 (27.2, 41.9)<0.05-
Omicron2931/486028.4 (7.9, 49.0)<0.0597.5%
Wild-type183659/706952.1 (44.0, 60.1)<0.0598.0%
Fever or Feverishness
Alpha110/3243.1 (1.2, 5.0)<0.05-
Omicron3178/11,5358.0 (−1.7, 17.7)>0.0595.2%
Wild-type9101/36812.6 (1.3, 3.8)<0.0590.9%
Fatigue
Alpha3494/76066.1 (42.2, 89.9)<0.0598.1%
Beta1295/219813.4 (12.0, 14.8)<0.05-
Delta140/16224.7 (18.1, 31.3)<0.05-
Omicron23457/15,84818.1 (0.4, 35.8)<0.0599.9%
Wild-type191234/609426.3 (20.7, 31.9)<0.0597.3%
Muscle weakness
Delta142/13543.1 (2.2, 4.0)<0.05-
Omicron130/24512.2 (8.1, 16.3)<0.05-
Wild-type470/17304.2 (1.5, 6.9)<0.0587.7%
Myalgia
Alpha174/32422.8 (18.3, 27.4)<0.05-
Delta169/13545.1 (3.9, 6.3)<0.05-
Omicron31346/11,53911.7 (8.3, 15.1)<0.0564.8%
Wild-type11235/27279.4 (6.3, 12.5)<0.0596.0%
Joint pain or arthralgia
Alpha153/30117.6 (13.3, 21.9)<0.05-
Omicron42124/11,73214.9 (8.3, 21.4)<0.0593.4%
Wild-type4152/60224.3 (6.6, 42.0)<0.0595.8%
Headache
Alpha145/32465.8 (47.7, 83.9)<0.05-
Beta18/219834.6 (27.2, 41.9)<0.05-
Delta532/151628.4 (7.9, 49.0)<0.0582.1%
Omicron53276/16,15752.1 (44.0, 60.1)<0.0599.9%
Wild-type1624/760410.0 (7.6, 12.4)<0.0595.8%
Dizziness or Vertigo
Delta11/1620.6 (−0.6, 1.8)>0.05-
Omicron32023/60741.6 (−0.8, 4.0)>0.0590.1%
Wild-type6175/30985.9 (2.7, 9.2)<0.0596.7%
Olfactory abnormalities
Omicron42651/16,12310.2 (−3.2, 23.6)>0.0599.8%
Wild-type446/7737.0 (2.7, 11.4)<0.0584.7%
Olfactory loss
Delta123/13541.7 (1.0, 2.4)<0.05-
Omicron162/22227.9 (22.0, 33.8)<0.05-
Wild-type9418/372513.1 (8.5, 17.8)<0.0595.1%
Taste abnormalities
Omicron42030/16,0908.7 (−2.3, 19.7)>0.0599.8%
Wild-type340/7037.1 (1.0, 13.2)<0.0590.9%
Taste loss
Alpha121/3017.0 (4.1, 9.9)<0.05-
Beta112/21980.5 (0.2, 0.9)<0.05-
Delta134/13542.5 (1.7, 3.3)<0.05-
Omicron150/22222.5 (17.0, 28.0)<0.05-
Wild-type7328/351510.4 (6.1, 14.6)<0.0594.4%
Hair loss
Omicron21572/11,01918.2 (8.2, 28.2)<0.0576.6%
Wild-type7209/30186.8 (3.4, 10.1)<0.0594.2%
Cutaneous or Skin disorders
Wild-type6156/37383.9 (2.1, 5.7)<0.0588.3%
Rash5666/16,5483.3 (0.4, 6.1)<0.0599.3%
Omicron4665/16,2044.2 (0.3, 8.1)<0.0599.5%
Wild-type11/3440.3 (-0.3, 0.9)>0.05-
Respiratory symptoms
Cough
Alpha287/45223.7 (2.0, 45.5)<0.0595.7%
Delta13/1621.9 (−0.2, 3.9)>0.05-
Gamma134/15621.8 (15.3, 28.3)<0.05-
Omicron21470/15,7686.8 (−5.1, 18.7)>0.0599.9%
Wild-type21853/769113.4 (10.4, 16.5)<0.0597.4%
Dyspnea
Alpha2125/42934.2 (8.3, 60.1)<0.0596.4%
Beta137/21971.7 (1.1, 2.2)<0.05-
Delta114/13541.0 (0.5, 1.6)<0.05-
Gamma168/15843.0 (35.3, 50.8)<0.05-
Omicron2177/48609.2 (−3.3, 21.6)>0.0596.3%
Wild-type201684/746923.3 (16.2, 30.5)<0.0598.9%
Expectoration
Wild-type580/9987.5 (2.9, 12.1)<0.0594.8%
Nasal congestion
Alpha152/32416.0 (12.1, 20.0)<0.05-
Omicron118/46380.4 (0.2, 0.6)<0.05-
Wild-type535/10492.8 (0.4, 5.1)<0.0585.5%
Sore throat
Alpha119/3245.9 (3.3, 8.4)<0.05-
Delta19/13540.7 (0.2, 1.1)<0.05-
Omicron2991/15,8464.5 (−3.7, 12.7)>0.0599.9%
Wild-type326/6354.3 (0.9, 7.8)<0.0573.0%
mMRC = 0
Alpha197/31231.1 (26.0, 36.2)<0.05-
Wild-type5702/100554.7 (33.9, 75.5)<0.0598.3%
mMRC ≥ 1
Alpha1215/31268.9 (63.8, 74.0)<0.05-
Omicron125/7334.2 (23.4, 45.1)<0.05-
Wild-type6350/112544.1 (26.3, 62.0)<0.0597.9%
Cardiovascular symptoms
Short Breath
Alpha1175/32753.5 (48.1, 58.9)<0.05-
Delta114/1628.6 (4.3, 13.0)<0.05-
Omicron13444/11,18330.8 (29.9, 31.7)<0.05-
Wild-type5215/153017.6 (9.5, 25.8)<0.0596.5%
Palpitations
Delta17/13540.5 (0.1, 0.9)<0.0596.8%
Omicron387/49565.9 (1.1, 10.7)<0.05-
Wild-type9191/34545.7 (3.2, 8.3)<0.0597.5%
Gastrointestinal symptoms
≥1 symptoms
Wild-type535/16031.8 (0.2, 3.3)<0.0584.3%
Loss of appetite
Delta253/15162.2 (−0.9, 5.4)>0.0593.7%
Omicron226/31811.9 (−3.8, 27.6)>0.0590.6%
Wild-type428/8763.0 (0.7, 5.3)<0.0574.6%
Nausea
Delta11/1620.6 (−0.6, 1.8)>0.05-
Omicron2505/11,35315.3 (−7.3, 37.9)>0.0594.9%
Wild-type314/7101.5 (−0.5, 3.5)>0.0575.9%
Diarrhea
Omicron2505/11,3534.4 (−1.5, 10.2)>0.0570.8%
Wild-type814/7102.5 (1.0, 3.9)<0.0592.5%
Abdominal pain
Omicron3636/16,1633.2 (−1.1, 7.5)>0.0599.7%
Wild-type658/21642.0 (0.5, 3.5)<0.0587.4%
Constipation
Delta135/13542.6 (1.7, 3.4)<0.05-
Omicron126/24510.6 (6.8, 14.5)<0.05-
Wild-type338/13703.1 (0.4, 5.8)<0.0592.2%
Neurological and psychiatric symptoms
≥1 symptoms
Wild-type8371/295013.8 (8.5, 19.2)<0.0595.7%
Paresthesias
Delta16/13540.4 (0.1, 0.8)<0.05-
Omicron11337/11,23611.9 (11.3, 12.5)<0.05-
Wild-type7161/177312.7 (7.7, 17.7)<0.0595.1%
Memory problem
Omicron11794/11,17416.1 (15.4, 16.7)<0.05-
Wild-type6225/148917.3 (8.7, 25.9)<0.0597.2%
Sleep difficulty
Alpha1151/32746.2 (40.8, 51.6)<0.05-
Delta251/15162.5 (0.2, 4.9)<0.0582.2%
Omicron43082/16,21118.7 (1.0, 36.5)<0.0599.9%
Wild-type11474/306724.5 (17.5, 31.5)<0.0598.5%
Depression 1
Delta11/1620.6 (−0.6, 1.8)>0.05-
Omicron12274/11,14920.4 (19.6, 21.1)<0.05-
Wild-type9411/358519.7 (10.1, 29.4)<0.0599.1%
Anxiety
Delta11/1620.6 (−0.6, 1.8)>0.05-
Omicron11196/11,17410.7 (10.1, 11.3)<0.05-
Wild-type11442/313415.3 (9.7, 20.8)<0.0596.8%
Difficulty concentrating
Omicron23542/15,81716.0 (−14.5, 46.4)>0.05100.0%
Wild-type6370/227623.3 (14.9, 31.6)<0.0596.1%
PFT
FEV1 < 80%
Alpha131/12325.2 (17.5, 32.9)<0.05-
Wild-type439/30213.4 (7.0, 19.9)<0.0562.9%
TLC < 80%
Alpha130/11127.0 (18.8, 35.3)<0.05-
Delta176/12162.8 (54.2, 71.4)<0.05-
Wild-type498/59617.2 (8.6, 25.8)<0.0587.8%
DLCO < 80%
Alpha150/11145.0 (35.8, 54.3)<0.05-
Wild-type5816/130259.2 (40.4, 78.1)<0.0596.7%
CT results
CT abnormalities
Wild-type111540/220660.5 (40.4, 80.6)<0.0599.2%
GGO
Wild-type12403/123138.9 (26.8, 51.0)<0.0595.7%
Consolidation
Wild-type521/3885.4 (0.8, 9.9)<0.0580.6%
Fibrosis
Wild-type9340/179024.4 (13.3, 35.4)<0.0596.3%
Bronchiectasis
Wild-type7195/89222.2 (9.7, 34.7)<0.0596.6%
EQ-5D-5L
Mobility
Alpha165/12850.8 (42.1, 59.4)<0.05-
Omicron128/7338.4 (27.2, 49.5)<0.05-
Wild-type399/83711.7 (9.5, 13.9)<0.050.0%
Personal care
Omicron128/7368.5 (57.8, 79.1)<0.05-
Wild-type399/8372.8 (−0.3, 6.0)>0.0588.5%
Usual activity
Alpha169/12853.9 (45.3, 62.5)<0.05-
Omicron137/7350.7 (39.2, 62.2)<0.05-
Wild-type279/59515.2 (5.2, 25.1)<0.0588.2%
Pain or discomfort
Alpha178/12860.9 (52.5, 69.4)<0.05-
Omicron152/7371.2 (60.8, 81.6)<0.05-
Wild-type3300/83837.2 (30.1, 44.3)<0.0576.9%
Anxiety and depression
Omicron153/7372.6 (62.4, 82.8)<0.05-
Wild-type4724/94128.0 (7.0, 49.0)<0.0598.8%
Abbreviations—mMRC: Modified medical research council dyspnea scale; PFT: pulmonary functional test; FEV1: forced expiratory volume in one second; TLC: total lung capacity; DLCO: carbon monoxide diffusing capacity; CT: computerized tomography; GGO: ground-glass opacity; and EQ-5D-5L: quality of life evaluation.
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Du, M.; Ma, Y.; Deng, J.; Liu, M.; Liu, J. Comparison of Long COVID-19 Caused by Different SARS-CoV-2 Strains: A Systematic Review and Meta-Analysis. Int. J. Environ. Res. Public Health 2022, 19, 16010. https://doi.org/10.3390/ijerph192316010

AMA Style

Du M, Ma Y, Deng J, Liu M, Liu J. Comparison of Long COVID-19 Caused by Different SARS-CoV-2 Strains: A Systematic Review and Meta-Analysis. International Journal of Environmental Research and Public Health. 2022; 19(23):16010. https://doi.org/10.3390/ijerph192316010

Chicago/Turabian Style

Du, Min, Yirui Ma, Jie Deng, Min Liu, and Jue Liu. 2022. "Comparison of Long COVID-19 Caused by Different SARS-CoV-2 Strains: A Systematic Review and Meta-Analysis" International Journal of Environmental Research and Public Health 19, no. 23: 16010. https://doi.org/10.3390/ijerph192316010

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop