COVID-19 Academic Resources Center
 

MDPI Comment on the COVID-19 Virus

Since 1996, MDPI has been committed to supporting the research community by providing the latest research freely available and making relevant and useful research available as quickly as possible. The world is current experiencing a pandemic of COVID-19, and researchers are working extremely hard to understand it and find a cure.

The values MDPI holds strongly are particularly important at the moment, and we will continue to publish relevant, peer-reviewed research as quickly as possible in open access format. This means that it will immediately be available for researchers, health professionals, and the general public to read, distribute, and reuse. We believe that scientific advancements will be crucial to overcoming this pandemic, and will do everything we can to support researchers working looking for solutions.

This page contains a variety of information related to COVID-19 available from MDPI, including journal articles, special issues, and preprints, among others.

Recent Publications

20 pages, 618 KB  
Systematic Review
Long-Term Kidney Outcomes After SARS-CoV-2 Infection in Children Aged 0–12 Years: A Systematic Review
by Saad Alhumaid, Abdullah Abdulrahman Alkhamees, Nourah Al Dossary, Anwar A Almuslim, Rabab Abbas Majzoub, Qasem M. Alalwan, Mohammed Jassim Alsaeed, Fahad Mohammed Aljowaisem, Manahi Ayadh Alqahtani, Abdulmohsen Ibrahim Alamer, Muath Ibrahim ALDuhailan, Dawood Adnan Al Nasser, Mohammed S Almuhanna, Mustafa A Al-Kamees, Hassan Ali Alhadab, Ali Ahmed Alsultan, Ali N Bukhamseen, Abdulaziz Abdullah Alabdullah, Kawther S. Alhaddad, Murtadha A. Alhumaid, Hassan M. Almusabeh, Yasin S. Almubarak, Rugayah Ahmed AlShayeb, Dalal Ahmed Alnami, Yaqoub Yousef Alatiyyah, Zainab Al Alawi and Muneera Alabdulqaderadd Show full author list remove Hide full author list
Children 2026, 13(1), 75; https://doi.org/10.3390/children13010075 - 2 Jan 2026
Abstract
Background: Acute kidney injury (AKI) is increasingly recognised in children with acute COVID-19 and multisystem inflammatory syndrome in children (MIS-C), yet the long-term renal consequences in younger paediatric populations remain unclear. Most studies focus on acute illness or mixed-age cohorts, with limited data [...] Read more.
Background: Acute kidney injury (AKI) is increasingly recognised in children with acute COVID-19 and multisystem inflammatory syndrome in children (MIS-C), yet the long-term renal consequences in younger paediatric populations remain unclear. Most studies focus on acute illness or mixed-age cohorts, with limited data specific to children aged 0–12 years. Objectives: This study aimed to systematically identify, evaluate, and synthesise evidence on post-acute (≥30 days) and long-term (≥90 days) kidney outcomes following SARS-CoV-2 infection or MIS-C in children aged 0–12 years, including chronic kidney disease (CKD), eGFR decline, proteinuria, haematuria, hypertension, and need for kidney replacement therapy. Methods: We searched MEDLINE, Embase, CINAHL, and PubMed (December 2019–30 November 2025), following PRISMA 2020 guidelines and a registered PROSPERO protocol (CRD420251241949). Observational studies reporting kidney outcomes ≥30 days post-infection in children aged 0–12 years were included. Risk of bias was assessed using the Newcastle–Ottawa Scale or ROBINS-I. Owing to heterogeneity and absence of ≥3 comparable datasets, a narrative synthesis was performed. Results: Seven studies met inclusion criteria (five MIS-C cohorts, two acute COVID-19 cohorts). Only a subset provided extractable data specific to children aged 0–12 years. Follow-up ranged from 30 days to 12 months; four studies reported outcomes ≥180 days. Across all studies, no incident CKD, sustained eGFR decline, or kidney replacement therapy were reported among children completing long-term follow-up; however, most long-term outcome data were derived from MIS-C cohorts with median ages around 8–11 years that included some adolescents, rather than exclusively children aged 0–12 years. One MIS-C study reported long-term hypertension in 14% of children. A cross-sectional Italian cohort of mild COVID-19 demonstrated hyperfiltration, proteinuria, and microhaematuria at ~3 months, though chronicity could not be assessed due to absence of baseline values. A large US EHR-based cohort identified increased CKD risk after COVID-19 in the broader <21-year population; however, 0–12-year-specific event counts were not reported, preventing quantitative synthesis for young children. Conclusions: Evidence on long-term kidney outcomes after SARS-CoV-2 infection in children aged 0–12 years remains limited, and only a small subset of studies provided extractable, age-specific data. On the other hand, MIS-C cohorts generally show favourable renal recovery, small sample sizes, lack of control groups, and short follow-up restrict confidence in these findings. Large paediatric EHR studies suggest potential long-term renal risk in broader paediatric populations, highlighting the need for age-stratified, prospective cohorts with serial eGFR, urine studies, and blood pressure assessments. Until definitive evidence emerges, structured renal follow-up may be warranted for children with AKI or MIS-C during COVID-19. Full article
(This article belongs to the Section Pediatric Infectious Diseases)
21 pages, 1189 KB  
Systematic Review
Surgical Timing and Safety of Breast Cancer Operations After COVID-19: A Prospective-Only Meta-Analysis of Cohort Studies
by Ioana-Georgiana Cotet, Diana-Maria Mateescu, Dragos-Mihai Gavrilescu, Andrei Marginean, Stefania Serban, Adrian-Cosmin Ilie, Cristina Guse, Ana-Maria Pah, Marius Badalica-Petrescu, Stela Iurciuc, Maria-Laura Craciun, Adina Avram and Cristina Tudoran
J. Clin. Med. 2026, 15(1), 341; https://doi.org/10.3390/jcm15010341 - 2 Jan 2026
Abstract
Background: The COVID-19 pandemic raised uncertainties regarding the safe timing of breast cancer surgery after SARS-CoV-2 infection, and robust prospective evidence has remained limited. Methods: We conducted a systematic review and meta-analysis of prospective cohort studies (2020–2024) investigating postoperative outcomes in breast cancer [...] Read more.
Background: The COVID-19 pandemic raised uncertainties regarding the safe timing of breast cancer surgery after SARS-CoV-2 infection, and robust prospective evidence has remained limited. Methods: We conducted a systematic review and meta-analysis of prospective cohort studies (2020–2024) investigating postoperative outcomes in breast cancer patients with confirmed SARS-CoV-2 infection ≤90 days before surgery versus contemporaneous non-infected controls treated at the same institutions and in the same period. PROSPERO CRD420251174613. Random-effects models (DerSimonian–Laird with Hartung–Knapp adjustment) were used to pool odds ratios (ORs) and 95% confidence intervals (CIs). Study quality was assessed with the Newcastle–Ottawa Scale, and certainty of evidence was rated using GRADE. Results: Twelve prospective cohort studies, including 7812patients, compared breast cancer surgery after recent confirmed SARS-CoV-2 infection over 90 days with contemporaneous non-infected controls treated at the same centres. Overall, recent infection was associated with higher 30-day postoperative complications (Clavien–Dindo ≥ II)compared to. non-infected patients (OR 2.01, 95% CI 1.44–2.81) and increased venous thromboembolism (3.6%vs. 1.2%; OR 3.12, 95% CI 1.29–7.55). Early surgery 14 days after infection carried the highest risk of complications (OR 4.38, 95 CI 2.31–8.30), whereas operations performed ≥6 weeks yielded outcomes comparable to non-infected controls (OR 1.03, 95 CI 0.81–1.31); 30-day mortality remained very low (0.3). Conclusions: Breast cancer surgery after SARS-CoV-2 infection is associated with excess perioperative risk only when performed within the first two weeks. Delaying surgery to approximately six weeks minimises complications and VTE without compromising short-term safety. Full article
(This article belongs to the Special Issue Sequelae of COVID-19: Clinical to Prognostic Follow-Up)
28 pages, 4974 KB  
Article
Global Patterns and Temporal Trends in Ovarian and Uterine Cancer Mortality Attributable to High Body-Mass Index, 1990–2023
by Irena Ilic, Vladimir Jakovljevic, Srdjan Lazic and Milena Ilic
Cancers 2026, 18(1), 157; https://doi.org/10.3390/cancers18010157 - 2 Jan 2026
Abstract
Background/Objectives: The risk factors for ovarian and uterine cancer remain insufficiently known. This study aimed to assess global trends in mortality from ovarian and uterine cancer attributable to high body-mass index (BMI) in 1990–2023. Methods: An observational epidemiological study was conducted. [...] Read more.
Background/Objectives: The risk factors for ovarian and uterine cancer remain insufficiently known. This study aimed to assess global trends in mortality from ovarian and uterine cancer attributable to high body-mass index (BMI) in 1990–2023. Methods: An observational epidemiological study was conducted. The age-standardized rates (ASRs) of mortality were retrieved from the Global Burden of Disease study. Trends were evaluated using joinpoint analysis. The Average Annual Percentage Change (AAPC, %), with a 95% Confidence Interval (CI), was calculated. Results: Globally, the trend in ASRs of ovarian cancer deaths attributable to high BMI increased significantly (AAPC = +0.4%, 95% CI = 0.3 to 0.5). The growth trend in South Asia (AAPC = +8.7%, 95% CI = 8.1 to 9.2) was 30 times greater than in Eastern Europe (AAPC = +0.3%, 95% CI = 0.1 to 0.5). Declining trends in mortality from ovarian cancer were observed only in Australasia (AAPC = −0.2%, 95% CI = −0.4 to −0.1), High-income North America (AAPC = −0.3%, 95% CI = −0.6 to −0.0), and Western Europe (AAPC = −0.7%, 95% CI = −0.8 to −0.6). For uterine cancer, the global trend of mortality also increased (AAPC = +0.1, 95% CI = 0.0 to 0.2), with the trend growing fastest in South Asia (AAPC = +4.2%, 95% CI = 4.0 to 4.4). Decreasing trends in mortality from uterine cancer due to high BMI were observed only in Central Asia (AAPC = −0.6%, 95% CI = −0.9 to −0.4), East Asia (AAPC = −2.2%, 95% CI = −2.6 to −1.8), and Southern Latin America (AAPC = −0.4%, 95% CI = −0.6 to −0.1). Additionally, an accelerated increase in mortality trends for both ovarian and uterine cancer attributable to high BMI was observed in 2020–2023, which corresponds to the period of the COVID-19 pandemic. Conclusions: Further analytical epidemiological studies are required to clarify the relationship between ovarian and uterine cancer and high BMI. Full article
(This article belongs to the Section Cancer Epidemiology and Prevention)
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13 pages, 909 KB  
Review
Single-Use Flexible Bronchoscopy: Advances in Technology and Applications
by Siti Amanina Azman and Marcus Peter Kennedy
Diagnostics 2026, 16(1), 150; https://doi.org/10.3390/diagnostics16010150 - 2 Jan 2026
Abstract
With advances in scope and imaging technology, the use of single-use flexible bronchoscopy (SUFB) has broadened beyond intensive care units and operating rooms to bronchoscopy units, with an expanding body of literature suggesting adequate and comparable procedure outcomes, including airway inspection, bronchoalveolar lavage, [...] Read more.
With advances in scope and imaging technology, the use of single-use flexible bronchoscopy (SUFB) has broadened beyond intensive care units and operating rooms to bronchoscopy units, with an expanding body of literature suggesting adequate and comparable procedure outcomes, including airway inspection, bronchoalveolar lavage, endobronchial brushing and endobronchial biopsy, in comparison to standard reusable flexible bronchoscopy (RFB). Advantages such as mobility, ease of use and lack of requirement for cleaning staff during the COVID-19 pandemic led to a global increase in usage, with many companies developing SUFB as part of their bronchoscopy portfolio. In parallel, there has been more attention and initiatives to minimise the risk of infection transmission related to bronchoscopy. RFB requires maximum adherence to manufacturer-recommended cleaning protocols. However, evidence of transmissible organisms after cleaning is reported in healthcare settings of all types. After initial benchtop, retrospective and single-arm studies, comparative bronchoscopy studies are identifying that SUFB are as versatile and non-inferior to RFB. However, cost-effectiveness and sustainability factors have to be included in deciding the use of SUFB in routine practice. Full article
(This article belongs to the Special Issue Advances in Interventional Pulmonology)
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19 pages, 355 KB  
Review
Feline Infectious Peritonitis: A Challenging Diagnostic and Therapeutic Labyrinth
by Violetta Iris Vasinioti, Maria Stella Lucente, Cristiana Catella, Canio Buonavoglia, Nicola Decaro, Annamaria Pratelli and Paolo Capozza
Animals 2026, 16(1), 128; https://doi.org/10.3390/ani16010128 - 2 Jan 2026
Abstract
Feline coronaviruses (FCoVs) are ubiquitous pathogens, exhibiting high prevalence across feline populations worldwide. Although the virulent mutated biotype feline infectious peritonitis virus (FIPV) is observed in only a small percentage of cats, it causes a systemic and often fatal disease. Diagnosis of feline [...] Read more.
Feline coronaviruses (FCoVs) are ubiquitous pathogens, exhibiting high prevalence across feline populations worldwide. Although the virulent mutated biotype feline infectious peritonitis virus (FIPV) is observed in only a small percentage of cats, it causes a systemic and often fatal disease. Diagnosis of feline infectious peritonitis (FIP) is challenging due to its non-specific clinical signs and the difficulty in differentiating between the two biotypes, feline enteric coronavirus (FECV) and FPIV. Currently, veterinarians rely on a combination of diagnostic methods, integrating laboratory tests, anamnesis and clinical signs to improve the diagnostic accuracy of FIP. Once considered untreatable, FIP now benefits from recent pharmacological advances that suggest promising therapeutic options, including antiviral drugs and immunomodulatory therapies. Despite these developments, the lack of an effective vaccine and definitive curative treatment highlights the need for continued research. This review provides a comprehensive analysis of the current literature on diagnostic and treatment approaches for FIP. The aim is to improve understanding of the available options and strategies for FIP to mitigate its severe consequences. Full article
(This article belongs to the Special Issue Prevention and Control for Animal Transmissible Diseases)
15 pages, 2165 KB  
Article
Morphological and Immunohistochemical Characteristics of Liver Inflammation in Patients with a History of COVID-19
by Ilze Strumfa, Ludmila Viksna, Oksana Kolesova, Ieva Vanaga, Haralds Plaudis, Jelena Storozenko, Boriss Strumfs, Janis Pavulans and Romans Uljanovs
Viruses 2026, 18(1), 68; https://doi.org/10.3390/v18010068 - 2 Jan 2026
Abstract
The COVID-19 pandemic caused more than seven million deaths, mostly via acute respiratory distress syndrome with microvascular thrombosis. Compared to the amount of information about pulmonary pathology, information about COVID-19-induced liver lesions is scarce, especially with regard to the long-term consequences. The aim [...] Read more.
The COVID-19 pandemic caused more than seven million deaths, mostly via acute respiratory distress syndrome with microvascular thrombosis. Compared to the amount of information about pulmonary pathology, information about COVID-19-induced liver lesions is scarce, especially with regard to the long-term consequences. The aim of our study was to evaluate inflammatory, vascular and fibrotic changes in hepatobiliary tissues of patients with a history of COVID-19 (post-COVID-19 patients). Based on the Knodell score, moderate portal inflammation was observed in 41.2% of post-COVID-19 patients, contrasting with 14.3% of control cases (p = 0.06). Moderate periportal inflammation was present in 26.5% and 7.1% of patients, respectively (p = 0.08). Post-COVID-19 patients showed higher counts of CD3+ lymphocytes (p = 0.02) and lower counts of CD68+ macrophages (p = 0.04), as well as more frequent and extensive regenerative changes in hepatocytes and the biliary epithelium (p = 0.0007). We did not find significant fibrosis or pathological changes in blood vessels, and only mild steatosis was observed in both groups. Full article
(This article belongs to the Special Issue Coronavirus Pathogenesis and Virus-Host Interaction)
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Sequencing Techniques and Genomics Technologies to Help with Diagnostics and Virus Characterization – Focus on COVID 19
edited by , Hugh E. Olsen, and
submission deadline 15 Apr 2021 | 10 articles | Viewed by 71354
Keywords: Genomics technologies; Sequencing techniques; Metagenomics; Virus sequencing; Genetic diagnostics; qPCR; Nanopore sequencing; Single-molecule real-time (SMRT) sequencing; Next-generation sequencing (NGS); Third-generation sequencing; Virus characterization; Long-read sequencing; Comparative genomics; Functional genomics; Diagnostic tests; Infectious diseases; Pandemic; SARS-CoV-2; COVID-19; Coronavirus; Genomic epidemiology; Population stratification; Genetic susceptibility; Host interactions
(This special issue belongs to the Section Technologies and Resources for Genetics)
Advances in SARS-CoV-2 Variants and Vaccines
edited by Scott Roberts
submission deadline 20 Jan 2026 | Viewed by 248 | Submission Open
Keywords: SARS-CoV-2; COVID-19; vaccine; epidemiology; public health; preparedness
(This special issue belongs to the Section Infectious Diseases)
Recent Advances in Pathophysiology and Immunology Related to SARS-CoV-2 Infection
edited by
submission deadline 20 Jan 2026 | 9 articles | Viewed by 15965 | Submission Open
Keywords: SARS-CoV-2; COVID-19; immunology; pathophysiology; immunopathology
(This special issue belongs to the Section Molecular Pathology, Diagnostics, and Therapeutics)
Rehabilitation and Treatment of Post-COVID-19 Condition submission deadline 20 Jan 2026 | 1 articles | Viewed by 876 | Submission Open
Keywords: post-COVID-19 condition; myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS); comorbidities; interdisciplinary; multimodal; digital medicine; rehabilitation; treatment; health-related quality of life; disability; return to work
(This special issue belongs to the Section Clinical Rehabilitation)
TMPRSS2 and Other Host Factors in Influenza Virus and Coronavirus Infections
edited by and Sze Keong Tey
submission deadline 31 Jan 2026 | 2 articles | Viewed by 6713 | Submission Open
Keywords: TMPRSS2; host factors; influenza virus; coronavirus; viral infection; treatment of viral diseases
(This special issue belongs to the Section Human Virology and Viral Diseases)
Analysis of Modeling and Statistics for COVID-19, 2nd edition submission deadline 31 Jan 2026 | 2 articles | Viewed by 1771 | Submission Open
Keywords: COVID-19 statistics; epidemiological modeling; time series analysis; prediction techniques; outbreak spatial diffusion; daily reproduction number; contagion modeling; viral mutation modeling; virulence mechanisms; host immunity modeling; mitigation measures dynamics; vaccination policy

State-of-the-Art Webinars on COVID-19


WEBINAR 1: How to Avoid a New Lockdown?

The first webinar in the series, held on 17 April 2020, saw both Prof. Dr. Antoine Flahault, Director of the Institute of Global Health, University of Geneva, Switzerland, and Prof. Dr. Evelyne Bischof, Associate Professor, Shanghai University of Medicine and Health Sciences, Shanghai, China and Research physician, University Hospital of Basel, Basel, Switzerland speak on this topic.

The recording can be found here.

WEBINAR 2: Coronaviruses: History, Replication, Innate Immune Antagonism

The second webinar in the series, entitled “Coronaviruses: history, replication, innate immune antagonism”, saw Prof. Dr. Susan R. Weiss, Professor of Microbiology, Perelman School of Medicine, University of Pennsylvania speak on this topic.

The recording can be found here.

WEBINAR 3: Could the COVID-19 Crisis be the Opportunity to Make Cities Carbon Neutral, Liveable and Healthy

The third webinar in this series was presented by Prof. Dr. Mark Nieuwenhuijsen, a world leading expert in environmental exposure assessment, epidemiology, and health risk/impact assessment with a strong focus and interest on healthy urban living. 

The recording can be found here

WEBINAR 4: COVID-19 - Global Supply Chains and the SDGs

For the fourth webinar of this series, Prof. Dr. Max Bergman, Dr. Dorothea Schostok and Prof. Dr. Patrick Paul Walsh gave a presentation on Global Supply Chains and the SDGs. 

The recording can be found here.

WEBINAR 5: The New Role of Family Physicians in Times of COVID-19

The fifth webinar of the COVID-19 Series saw Prof. Dr. Christos Lionis discuss the new role of family physicians that emerged during the COVID-19 pandemic.

The recording can be found here.

WEBINAR 6: Survey on Symptoms/Signs, Protective Measures, Level of Awareness and Perception Regarding COVID-19 Outbreak among Dentists

In the sixth webinar of this series, Prof. Dr. Guglielmo Campus and Prof. Dr. Maria Grazia present and discuss the risk and the preventions that can and should be taken by dentists during this pandemic.

The recording can be found here.

WEBINAR 7: Living with COVID-19: An Early Intervention Therapeutic Strategy to Control the Pandemic

The seventh webinar of the COVID-19 series, Dr. Hamid Merchant discussed the different therapeutic strategies that can be adopted in the early stages of the infection.

The recording can be found here.

WEBINAR 8: Impact of COVID-19 on Routine Immunization, Reproduction and Pregnancy Outcome

For the eighth COVID-19 webinar, Prof. Dr. Jon Øyvind Odland discussed the effect that COVID-19 seems to have on pregnant women; whereas Prof. Dr. Giovanni Gabutti discussed the role of routine immunization as a way of fighting COVID-19.

The recording can be found here.

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