Journal Description
COVID
COVID
is an international, peer-reviewed, open access journal on the study of coronaviruses, coronavirus-related diseases and global impact, published monthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within ESCI (Web of Science), Scopus, CAPlus / SciFinder, and other databases.
- Journal Rank: CiteScore - Q2 (Immunology and Microbiology (miscellaneous))
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 20.6 days after submission; acceptance to publication is undertaken in 3.4 days (median values for papers published in this journal in the first half of 2025).
- Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Impact Factor:
1.0 (2024);
5-Year Impact Factor:
1.0 (2024)
Latest Articles
A Retrospective Look at Early COVID-19 Treatment and Outcomes in Two Tertiary Centers in Türkiye and Bosnia & Herzegovina
COVID 2025, 5(12), 194; https://doi.org/10.3390/covid5120194 - 21 Nov 2025
Abstract
During the early months of the COVID-19 pandemic, treatment protocols varied substantially among countries and even between hospitals. This study compared the clinical characteristics, management strategies, and outcomes of hospitalized COVID-19 patients treated in tertiary centers in Türkiye and Bosnia and Herzegovina. We
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During the early months of the COVID-19 pandemic, treatment protocols varied substantially among countries and even between hospitals. This study compared the clinical characteristics, management strategies, and outcomes of hospitalized COVID-19 patients treated in tertiary centers in Türkiye and Bosnia and Herzegovina. We retrospectively analyzed 1338 adults hospitalized with laboratory-confirmed SARS-CoV-2 infection: 657 patients in Tuzla (Bosnia and Herzegovina, June–December 2020) and 681 in İstanbul (Turkiye, April–May 2020). Demographic, clinical, and laboratory data, treatment details (including favipiravir use), need for invasive or non-invasive mechanical ventilation, and in-hospital mortality were extracted from medical records. Patients in Bosnia and Herzegovina were older (61.6 ± 14.4 vs. 56.9 ± 15.8 years; p < 0.001) and had longer hospital stays (9.0 ± 5.5 vs. 7.7 ± 6.1 days; p < 0.001). In the Bosnian cohort, leukocyte, neutrophil, platelet, ferritin, CRP, troponin, creatinine, AST, and ALT levels were significantly higher, whereas hemoglobin and D-dimer levels were lower. The need for ventilatory support was greater in Bosnia and Herzegovina (15.1% vs. 12.2%, p < 0.001), and overall mortality was higher (25.7% vs. 9.3%, p < 0.001). No mortality difference was observed between patients treated and not treated with favipiravir. Despite similar inclusion criteria, patients in Bosnia and Herzegovina exhibited more severe disease, greater organ involvement, and higher mortality than those in Turkiye. Favipiravir use did not influence survival. Inter-country comparisons highlight how differing patient profiles and treatment protocols may impact COVID-19 outcomes; however, interpretation should consider that the two centers contributed data from different phases of the 2020 pandemic, and that country-level differences in circulating variants, healthcare capacity, hospital strain, and evolving clinical guidelines may also have influenced the observed patterns.
Full article
(This article belongs to the Section COVID Clinical Manifestations and Management)
Open AccessArticle
Long-Term Myocardial Involvement and Outcome in the Post-COVID-19 Condition
by
Miltiadis Georgiadis, Nuriye Akyol, Lars Kamper, Nima Nadem-Boueini, Athanasios Ziakos, Patrick Haage, Melchior Seyfarth and Nadine Abanador-Kamper
COVID 2025, 5(11), 193; https://doi.org/10.3390/covid5110193 - 20 Nov 2025
Abstract
After SARS-CoV-2 infection, a subset of patients experience persistent cardiac symptoms, yet data on long-term cardiac involvement and clinical outcomes in the post-COVID-19 condition remain limited. This study aimed to investigate myocardial abnormalities using advanced cardiovascular magnetic resonance (CMR) imaging techniques in patients
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After SARS-CoV-2 infection, a subset of patients experience persistent cardiac symptoms, yet data on long-term cardiac involvement and clinical outcomes in the post-COVID-19 condition remain limited. This study aimed to investigate myocardial abnormalities using advanced cardiovascular magnetic resonance (CMR) imaging techniques in patients with ongoing cardiac symptoms for at least three months following COVID-19 diagnosis, and to assess their clinical outcomes. Between January 2021 and March 2022, 94 post-COVID-19 patients were examined at a median of 99 days (IQR 92–110) after diagnosis and compared to 100 controls. The CMR assessment included the left ventricular ejection fraction (LVEF), myocardial T2 signal, late gadolinium enhancement (LGE), and myocardial strain parameters. Follow-up for major adverse cardiac events (MACEs) was conducted at a median of 269 days (IQR 144–352). While no significant differences in LVEF were observed, post-COVID-19 patients demonstrated significantly reduced peak radial and circumferential strain values, suggesting subclinical myocardial dysfunction. Additionally, these patients exhibited a higher event rate compared to controls (0.063 vs. 0; p = 0.029). These findings indicate that patients with cardiac symptoms following COVID-19 may exhibit subtle but measurable myocardial changes and an increased risk of adverse outcomes. The observed alterations in myocardial strain most likely reflect mild, subclinical myocardial involvement within the spectrum of post-COVID-19 effects, rather than a direct cause of persistent symptoms. Further research is warranted to determine the prognostic significance of these findings.
Full article
(This article belongs to the Section Long COVID and Post-Acute Sequelae)
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Open AccessArticle
Nasopharyngeal Proteomic Profiles from Patients Hospitalized Due to COVID-19 in Manaus, Amazonas, Brazil
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Cláudia P. M. Araújo, Carolina M. Vieira, Ketlen C. Ohse, Alessandra S. Silva, Sofia A. Cavalcante, Felipe G. Naveca, Fernanda N. Oliveira, James L. Crainey, Marcus V. G. Lacerda, Gisely C. Melo, Vanderson S. Sampaio, Michel Batista, Amanda C. Camillo-Andrade, Marlon D. M. Santos, Diogo B. Lima, Juliana de S. G. Fischer, Paulo C. Carvalho and Priscila F. Aquino
COVID 2025, 5(11), 192; https://doi.org/10.3390/covid5110192 - 18 Nov 2025
Abstract
This study investigated proteomic differences in nasopharyngeal swabs of SARS-CoV-2-infected patients from Manaus (Brazil) who were hospitalized during the devastating first wave of the COVID-19 pandemic, before the emergence of the deadly P1 SARS-CoV-2 strain. LC-MS/MS proteomic analysis compared 16 matched COVID-19 patient
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This study investigated proteomic differences in nasopharyngeal swabs of SARS-CoV-2-infected patients from Manaus (Brazil) who were hospitalized during the devastating first wave of the COVID-19 pandemic, before the emergence of the deadly P1 SARS-CoV-2 strain. LC-MS/MS proteomic analysis compared 16 matched COVID-19 patient profiles: eight survivors and eight fatalities. A total of 1604 proteins were identified in fatality swabs, and 981 in the swabs of survivors. Our study provides new insights into the cellular mechanisms underlying first-wave COVID-19 deaths from Manaus and identifies hypoxia-related HYOU1, endothelial injury-associated S100A10, and some viral replication proteins (DDX1/17, XPO1) as potential biomarkers of fatal infections. The proteomic profiles of the swabs taken from patients that died collectively suggest that many of the first wave COVID-19 fatalities in Manaus suffered immune-system collapse. Survivor patient swabs showed elevated levels of immune defense proteins (FN1, C4BPA, IGKV1-5), indicating effective antiviral responses. Gene ontology analysis revealed dysregulated secretory pathways in fatalities and did not detect the defense-response pathways in fatality-group datasets that were observed in survivor protein datasets. Interestingly, the NOS2 protein, previously associated with first-wave fatalities, was found exclusively in our fatality swabs.
Full article
(This article belongs to the Section Host Genetics and Susceptibility/Resistance)
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Open AccessArticle
Exploratory, Cross-Sectional Observations on Post-COVID-19 Respiratory Symptoms: A Multivariable Analysis
by
Patchareeya Amput, Arunrat Srithawong, Ajchamon Thammachai and Sirima Wongphon
COVID 2025, 5(11), 191; https://doi.org/10.3390/covid5110191 - 8 Nov 2025
Abstract
Background: This cross-sectional study reports exploratory observations on respiratory symptom patterns in individuals with prior coronavirus disease 2019 (COVID-19), evaluating associations with exercise habits, number of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection episodes, vaccine doses received, body mass index (BMI), age, sex,
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Background: This cross-sectional study reports exploratory observations on respiratory symptom patterns in individuals with prior coronavirus disease 2019 (COVID-19), evaluating associations with exercise habits, number of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection episodes, vaccine doses received, body mass index (BMI), age, sex, and comorbidities. Methods: A total of 240 participants were assessed for age, sex, height, weight, BMI, comorbidities, SARS-CoV-2 infection episodes, vaccine doses received, and exercise habits; the self-reported duration of symptomatic periods was summarized descriptively and was not modeled as an exposure or outcome. Results: Compared with the first SARS-CoV-2 infection episode (reference), patients who experienced a second episode had higher odds of dyspnea (adjusted odds ratio; OR = 7.61; 95% confidence interval CI = 1.54–37.66). In univariate analysis, patients who received three vaccine doses had lower odds of dyspnea than those who received two doses (OR = 0.39; 95% CI = 0.16–0.98), but this association was not significant after adjustment (adjusted OR = 0.46; 95% CI = 0.13–1.63). After adjustment, patients who exercised had lower odds of secretion compared with those who did not (adjusted OR = 0.30; 95% CI = 0.12–0.73). Conclusions: These cross-sectional, hypothesis-generating observations suggest higher adjusted odds of dyspnea among individuals with repeat infection and lower adjusted odds of sputum among those reporting regular exercise; estimates are imprecise and subject to residual confounding due to unbalanced group sizes. Confirmation in larger, longitudinal cohorts is required.
Full article
(This article belongs to the Section COVID Clinical Manifestations and Management)
Open AccessArticle
Determining the Impact of Exogenous Factors in Acute Respiratory Infections Using a Mathematical Epidemiological Model—Case Study of COVID-19 in a Peruvian Hospital
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Pedro I. Pesantes-Grados, Emma Cambillo-Moyano, Erasmo H. Colona-Vallejos, Libertad Alzamora-Gonzales, Dina Torres Gonzales, Giannina Tineo Pozo, Elena Chamorro Chirinos, Cynthia Lorenzo Quito, Elias E. Aguirre-Siancas, Eliberto Ruiz-Ramirez and Roxana López-Cruz
COVID 2025, 5(11), 190; https://doi.org/10.3390/covid5110190 - 4 Nov 2025
Abstract
In this study, we develop and analyze an extended SEIR-type compartmental model that incorporates vaccination and treatment to describe the dynamics of acute respiratory infection transmission. The model subdivides the infectious population into several symptomatic stages and an asymptomatic class, which allows the
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In this study, we develop and analyze an extended SEIR-type compartmental model that incorporates vaccination and treatment to describe the dynamics of acute respiratory infection transmission. The model subdivides the infectious population into several symptomatic stages and an asymptomatic class, which allows the evaluation of control strategies across different levels of infection severity. The basic reproduction number is analytically derived, and its sensitivity to vaccination and treatment rates is examined to assess the impact of public health interventions on epidemic control. Numerical simulations demonstrate that the joint implementation of vaccination and treatment can markedly reduce disease prevalence and lead to infection elimination when . The results emphasize the critical role of parameter interactions in determining disease persistence and show that combining both interventions produces stronger epidemiological effects than either one alone. Machine learning techniques, specifically Support Vector Machines (SVMs), are employed to classify epidemiological outcomes and support parameter estimation. The biological markers evaluated were not effective discriminants of infection status, underscoring the importance of integrating mechanistic modeling with data-driven approaches. This combined framework enhances the understanding of epidemic dynamics and improves the predictive capacity for decision-making in public health.
Full article
(This article belongs to the Special Issue Analysis of Modeling and Statistics for COVID-19, 2nd edition)
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Open AccessArticle
Mental Health in Primary School Children Before and During the COVID-19 Pandemic
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Benito León-del-Barco, María-Isabel Polo-del-Río, Santiago Mendo-Lázaro, Víctor-María López-Ramos, Carolina Bringas-Molleda and Julián Álvarez-Delgado
COVID 2025, 5(11), 189; https://doi.org/10.3390/covid5110189 - 3 Nov 2025
Abstract
The health crisis caused by COVID-19 led to a series of restrictive measures worldwide. Amongst them, a period of lockdown that resulted in a decrease in social contact, which had a series of effects at the emotional, educational, and social levels, the greatest
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The health crisis caused by COVID-19 led to a series of restrictive measures worldwide. Amongst them, a period of lockdown that resulted in a decrease in social contact, which had a series of effects at the emotional, educational, and social levels, the greatest concern being the mental health effects in minors. The aim of this study is to analyse mental health disorders affecting Primary Education students before and during the pandemic, at emotional, social and behavioural levels. A total of 1045 students from different educational centres, in 5th and 6th year of Primary Education, of both sexes and aged between 10 and 12 years old, took part in the study. The instrument used was the “Strengths and Difficulties Questionnaire, SDQ”, which measures mental health disorders in minors. The results indicate that during the pandemic there was an increase in emotional problems among minors, alongside a decrease in hyperactivity, conduct problems, and peer-related problems. Social distancing during the pandemic may have acted as a key mediating variable in the observed outcomes. It is concluded that these results are important in preventing psychological effects on the mental health of minors in crisis situations.
Full article
(This article belongs to the Section COVID Public Health and Epidemiology)
Open AccessArticle
COVID-19 Post-Pandemic Adaptation and Resilience: A Cross-Cultural Study of China and Canada
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Sarah-Mei Chen, Junru Yan, Fan Yang, Clara B. Rebello, Angelie M. Ignacio, Chao S. Hu and Gerald C. Cupchik
COVID 2025, 5(11), 188; https://doi.org/10.3390/covid5110188 - 2 Nov 2025
Abstract
The COVID-19 pandemic altered individuals’ worldviews. This study examined how cultural values shaped the ways students navigated stress and adapted after the COVID-19 pandemic. Drawing on Conservation of Resources (COR) Theory and cultural psychology frameworks of individualism and collectivism, we hypothesized that university
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The COVID-19 pandemic altered individuals’ worldviews. This study examined how cultural values shaped the ways students navigated stress and adapted after the COVID-19 pandemic. Drawing on Conservation of Resources (COR) Theory and cultural psychology frameworks of individualism and collectivism, we hypothesized that university students in two culturally distinct contexts—China and Canada—would demonstrate resilience differently. Chinese students would display collectivistic coping strategies (e.g., social responsibility and perspective-taking), while Canadian students would show resilience through individualistic strategies (e.g., personal reflection and self-efficacy). A total of 814 students completed a mixed-methods survey assessing resilience, cognitive reflection, and post-pandemic adaptations. Quantitative data were analyzed using factor analysis and stepwise regression to identify predictors. Qualitative responses were thematically analyzed for context. Results revealed cultural differences in resilience and adaptation, with social responsibility, healthy habits, and third-person perspective-taking predicting the responses of Chinese students, whereas internal emotional processing and personal moral reflection predicting it for Canadian students. This study enhances cross-cultural understanding of resilience and adaptation after collective trauma.
Full article
(This article belongs to the Section COVID Public Health and Epidemiology)
Open AccessArticle
Mental Health Outcomes Among Physicians Following the COVID-19 Pandemic
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Politimi Kellartzi, Constantine Anetakis, Anna-Bettina Haidich, Vasileios Papaliagkas, Stella Mitka, Maria Anna Kyriazidi, Maria Nitsa and Maria Chatzidimitriou
COVID 2025, 5(11), 187; https://doi.org/10.3390/covid5110187 - 1 Nov 2025
Abstract
The COVID-19 pandemic exposed the fragility of global health systems, as physicians faced extremely challenging conditions including excessive workloads, infection risk, and high patient mortality. We conducted a cross-sectional survey that aimed to assess the post-pandemic prevalence of anxiety, depression, and post-traumatic stress
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The COVID-19 pandemic exposed the fragility of global health systems, as physicians faced extremely challenging conditions including excessive workloads, infection risk, and high patient mortality. We conducted a cross-sectional survey that aimed to assess the post-pandemic prevalence of anxiety, depression, and post-traumatic stress disorder (PTSD) in a sample of Greek physicians who worked on the frontline during the SARS-CoV-2 (COVID-19) pandemic. An online survey was conducted between 1 March and 31 July 2023, in which 200 Greek physicians were invited via e-mail to voluntarily answer a confidential online questionnaire, and 58 of them responded. The survey included two clinically validated tools: the Patient Health Questionnaire-4 (PHQ-4) and the Impact of Event Scale—Revised (IES-R). Univariate correlations of 26 exposure variables with anxiety, depression, combined anxiety/depression, and PTSD were performed. In total, 58 eligible physicians (46.6% female) participated in this study. The rates of anxiety, depression, combined anxiety/depression, and PTSD were 27.5% (95% CI: 16.7–40.9), 31.0% (19.5–44.5), 22.4% (12.5–35.3), and 24.1% (13.9–37.2), respectively. Notably none of the physicians working in a laboratory developed any mental health symptoms. The following factors were found to be associated with the development of higher mental health symptoms: age ≤ 30, employment in healthcare ≤ 10 years, working in COVID-19 wards, working in intensive care units or COVID-19 wards, a history of mental health symptoms, a history of physical conditions, shortages of materials and equipment for diagnosing or treating patients, development of a disease other than COVID-19, and the development of a new mental health condition during the pandemic (p < 0.05 for all associations). Our findings highlight the need to better prepare physicians with adequate materials, infrastructure, and psychological support such that, in a potential future health crisis, they will not be at such high risk of mental health problems.
Full article
(This article belongs to the Section COVID Public Health and Epidemiology)
Open AccessArticle
The Impact of Fear of COVID-19 on Mood and Health During the First COVID-19 Lockdown Period in The Netherlands
by
Pantea Kiani, Pauline A. Hendriksen, Dana M. Dijkgraaf, Agnese Merlo, Maureen N. Zijlstra, Johan Garssen, Gillian Bruce, Andrew Scholey and Joris C. Verster
COVID 2025, 5(11), 186; https://doi.org/10.3390/covid5110186 - 1 Nov 2025
Abstract
Background: Fear of COVID-19 has been associated with adverse mental and physical health outcomes, yet evidence from The Netherlands is limited. This study investigated associations between fear of COVID-19, mood, quality of life, immune fitness, and related health variables during the first Dutch
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Background: Fear of COVID-19 has been associated with adverse mental and physical health outcomes, yet evidence from The Netherlands is limited. This study investigated associations between fear of COVID-19, mood, quality of life, immune fitness, and related health variables during the first Dutch national lockdown and identified key predictors of fear. Methods: In June–July 2020, n = 1020 Dutch adults completed an online survey assessing demographics, personality, mental resilience, pain sensitivity, pain catastrophizing, alcohol use, immune fitness, and mood. Retrospective ratings were provided for the pre-pandemic period (January–March 2020) and the first lockdown (March–May 2020). Fear of COVID-19 was measured using a modified Fear of COVID-19 Scale. Results: Overall, 13.2% of participants reported significant fear of COVID-19, which was associated with poorer mood, reduced quality of life, lower immune fitness, more severe COVID-19 symptoms, greater pain sensitivity, and higher levels of pain catastrophizing. Regression analysis explained 19.6% of the variance, with pre-pandemic anxiety (8.7%) and poorer immune fitness (3.4%) as the strongest predictors of fear of COVID-19, followed by lower psychoticism, lower mental resilience, older age, greater helplessness, and greater extraversion. Discussion: These findings suggest that a minority experienced high levels of fear of COVID-19 with substantial consequences, including negative effects on mood, immune fitness, and quality of life. The strong association with pre-existing anxiety and immune fitness highlights the need for early identification and targeted interventions for vulnerable groups to reduce psychological and physical health impacts in future public health crises.
Full article
(This article belongs to the Section COVID Public Health and Epidemiology)
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Resilience and Inequality in Public Health: An Empirical Analysis of Systemic Vulnerabilities and Care Strategies During COVID-19
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Tarek Sadraoui and Insaf Khelifi
COVID 2025, 5(11), 185; https://doi.org/10.3390/covid5110185 - 30 Oct 2025
Abstract
The COVID-19 pandemic has had a diverse impact worldwide, affecting all strata of society. This article examines the relationship between health system adaptation and socioeconomic inequality in countries and the WHO Eastern Mediterranean Region (WHO-EMR), and we suggest that the dynamics among government
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The COVID-19 pandemic has had a diverse impact worldwide, affecting all strata of society. This article examines the relationship between health system adaptation and socioeconomic inequality in countries and the WHO Eastern Mediterranean Region (WHO-EMR), and we suggest that the dynamics among government response, health system preparedness, and epidemic spread are calibrated by the present socioeconomic inequality. With the use of a panel dataset spanning February 2020 to March 2021 and both linear (PARDL) and nonlinear (PNARDL) estimation techniques, we find that more socioeconomically vulnerable regions were disproportionately hit by the efforts of the pandemic, even in the presence of containment measures. From our findings, we find that health system capacity measures, such as hospital bed density and primary healthcare expenditure, are positively related to long-term economic resilience, while antimicrobial drug resistance is strongly negatively related to it. The study emphasizes the need for selective policy interventions to protect the most disadvantaged groups, a finding of relevance for other high-inequality low- and middle-income countries.
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(This article belongs to the Section COVID Public Health and Epidemiology)
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Open AccessArticle
Post-Traumatic Stress Disorder, Anxiety, and Depression in Post-COVID-19 Patients Undergoing Psychotherapy: A Nonrandomized Clinical Trial
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Marilúcia M. Carrijo, Miriã C. Oliveira, Washington A. O. Canedo, João Pedro R. Afonso, Heren N. C. Paixão, Larissa R. Alves, Renata K. Palma, Iranse Oliveira-Silva, Carlos H. M. Silva, Rodrigo F. Oliveira, Deise A. A. P. Oliveira, Rodrigo A. C. Andraus, Rodolfo P. Vieira, Gianluca Castelnuovo, Paolo Capodaglio and Luís V. F. Oliveira
COVID 2025, 5(11), 184; https://doi.org/10.3390/covid5110184 - 25 Oct 2025
Abstract
Global estimates show a 17.9% prevalence of neuropsychiatric disorders in individuals recently hospitalized with COVID-19. Cognitive behavioral therapy (CBT) has been proposed as a nonpharmacological strategy to mitigate these effects. This study examined the potential effects of CBT on anxiety, depression, post-traumatic stress
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Global estimates show a 17.9% prevalence of neuropsychiatric disorders in individuals recently hospitalized with COVID-19. Cognitive behavioral therapy (CBT) has been proposed as a nonpharmacological strategy to mitigate these effects. This study examined the potential effects of CBT on anxiety, depression, post-traumatic stress disorder (PTSD), and quality of life (QoL) in post-COVID-19 patients. This prospective, nonrandomized, single-center clinical trial involved 15 patients (mean age 53.4 years) who underwent weekly CBT sessions for six weeks. Between-group differences in anxiety and depression scores were non-significant (p > 0.05); however, significant intragroup improvements were observed in anxiety (p = 0.01), depression (p = 0.01), and PTSD (p = 0.01) after the intervention. Thus, CBT was associated with reduced anxiety, depression, and PTSD as well as improved quality of life in post-COVID-19 patients. Improvements in QoL were noted mainly in the domains of functional capacity, vitality, emotional aspects, and mental health. While these findings suggest that CBT may be beneficial for post-COVID-19 patients, the small sample size, absence of a control group, and short follow-up period limit the strength of our conclusions. Therefore, the results should be considered preliminary, and further randomized controlled trials with larger sample sizes are warranted.
Full article
(This article belongs to the Special Issue Long COVID: Pathophysiology, Symptoms, Treatment, and Management)
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Mathematical Modelling and Analysis of Stochastic COVID-19 and Hepatitis B Co-Infection Dynamics
by
Michael Asamani Pobbi, Samuel Mindakifoe Naandam and Stephen Edward Moore
COVID 2025, 5(11), 183; https://doi.org/10.3390/covid5110183 - 25 Oct 2025
Abstract
The recent resurgence of COVID-19 in a Hepatitis B virus some endemic countries could lead to adverse outcomes. In this article, we formulate and analyse a mathematical model to explains the co-infection dynamics of Hepatitis B virus and COVID-19. Our aim is to
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The recent resurgence of COVID-19 in a Hepatitis B virus some endemic countries could lead to adverse outcomes. In this article, we formulate and analyse a mathematical model to explains the co-infection dynamics of Hepatitis B virus and COVID-19. Our aim is to investigate the effect of Hepatitis B virus prevention, COVID-19 prevention, COVID-19 vaccination, and environmental factors on transmission dynamics, and formulate conditions for extinction and persistence of the diseases. First, we derive the basic reproduction number for HBV only, COVID-19 only, and co-infection stochastic models using the next-generation matrix method. Next, we establish the conditions for stability in the stochastic sense for HBV only, COVID-19 only sub-models, and the co-infection model using suitable Lyapunov functions. Furthermore, we devote our attention to finding sufficient conditions for extinction and persistence. Finally, motivated by Ghana data, we applied the Euler–Murayama scheme to illustrate the dynamics of the co-infection, COVID-19, HBV, and the effect of some parameters on disease transmission dynamics by means of numerical simulations.
Full article
(This article belongs to the Special Issue Analysis of Modeling and Statistics for COVID-19, 2nd edition)
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Open AccessArticle
Health Professionals’ Safety in Facing the COVID-19 Pandemic: Perceptions from a Brazilian Municipality
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Alzilid Cintia Rodarte, Kelly Aline Rodrigues Costa, Herica Silva Dutra, Sílvia Manuela Dias Tavares da Silva, Selma Maria da Fonseca Viegas and Fernanda Moura Lanza
COVID 2025, 5(11), 182; https://doi.org/10.3390/covid5110182 - 24 Oct 2025
Abstract
Health professionals’ safety is directly linked to organizational culture, and during the COVID-19 pandemic, weaknesses at organizational, emotional, professional, and structural levels became evident. This study aimed to assess health professionals’ perceptions of their safety in facing the COVID-19 pandemic. A cross-sectional, descriptive,
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Health professionals’ safety is directly linked to organizational culture, and during the COVID-19 pandemic, weaknesses at organizational, emotional, professional, and structural levels became evident. This study aimed to assess health professionals’ perceptions of their safety in facing the COVID-19 pandemic. A cross-sectional, descriptive, and analytical study was conducted with professionals from the public health network of a Brazilian municipality who had taken medical leave due to COVID-19. Data were collected between October and December 2022 using the validated Questionnaire on Health Professional Safety in the COVID-19 Pandemic (QSP COVID-19), which consists of 30 items distributed across four domains: organizational, emotional, professional, and structural. A cut-off score ≥75 was considered a positive perception. Associations were tested using the chi-square test followed by the Bonferroni post hoc test, and multivariate logistic regression was applied to identify associated factors. Significance level: 5%. A total of 235 professionals participated, mostly women (81.7%), working in primary health care (68.1%), and employed under statutory contracts (74.5%). Only 50.6% reported an overall positive perception of safety. The emotional domain showed the highest score (85.5%), followed by the professional domain (74.0%). Organizational (50.6%) and structural (33.6%) domains had the lowest scores, reflecting shortcomings in infrastructure, human resources, and material supplies. In the multivariate analysis, temporary contracts, a 20 h workweek, and specific training were protective factors, whereas belonging to a risk group and being female increased the likelihood of negative perception in the structural dimension. Health professionals’ safety is supported by continuous education, emotional support, adequate infrastructure, professional recognition, participatory leadership, and strengthening of the safety culture.
Full article
(This article belongs to the Section COVID Public Health and Epidemiology)
Open AccessArticle
Characterization of the SARS-CoV-2 Mutation Pattern Generated In Vitro by the Antiviral Action of Lycorine
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Silvina Soledad Maidana, Sonia Alejandra Romera, Ana Marandino, Rocío Lucia Tau, Juan Mauel Shammas, Yanina Panzera and Ruben Pérez
COVID 2025, 5(11), 181; https://doi.org/10.3390/covid5110181 - 23 Oct 2025
Abstract
SARS-CoV-2 persists worldwide, driving the demand for effective antivirals that inhibit replication and limit the emergence of resistant variants. Lycorine, a non-nucleoside inhibitor of SARS-CoV-2 RNA-dependent RNA polymerase, exhibits antiviral activity without direct mutagenic effects. Here, we examine the occurrence of single-nucleotide variants
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SARS-CoV-2 persists worldwide, driving the demand for effective antivirals that inhibit replication and limit the emergence of resistant variants. Lycorine, a non-nucleoside inhibitor of SARS-CoV-2 RNA-dependent RNA polymerase, exhibits antiviral activity without direct mutagenic effects. Here, we examine the occurrence of single-nucleotide variants (SNVs) and insertions/deletions (indels) in SARS-CoV-2 B.1.499 strain during serial passages in Vero cells, comparing lycorine-treated cultures (2.5 and 5 µg/mL) with untreated controls. Whole-genome sequencing was used to assess mutation patterns and frequencies. Lycorine-treated passages displayed greater variant diversity than controls, with fixed mutations mainly affecting non-structural proteins (Nsp3-F1375A, Nsp5-L50F, and Nsp14-G265D) and the envelope protein (E-S6L). A 15-nucleotide deletion in the spike gene (QTQTN motif) occurred in both groups but became fixed only in untreated passages, suggesting negative selection under lycorine pressure. Notably, the L50F mutation in Nsp5, previously linked to nirmatrelvir resistance, was found exclusively in lycorine-treated passages. Additionally, a 1-nucleotide deletion in the accessory gene ORF8, detected only under lycorine treatment, resulted in a frameshift mutation that added four amino acids, potentially altering the protein’s function. Overall, lycorine induces a distinct mutation profile, favoring replication-related variants while suppressing deleterious deletions. These findings suggest potential mechanisms of cross-resistance and highlight the importance of monitoring resistance during clinical use.
Full article
(This article belongs to the Special Issue Advances in Coronaviruses Research: Pathogenesis, Immunity, and Antivirals)
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Open AccessArticle
HIV Treatment Services Among Men Who Have Sex with Men During COVID-19 in Limpopo Province, South Africa
by
Betty Sebati, Edith Phalane, Amukelani Bilankulu and Refilwe Nancy Phaswana-Mafuya
COVID 2025, 5(10), 180; https://doi.org/10.3390/covid5100180 - 20 Oct 2025
Abstract
Men who have sex with men (MSM) are part of the key populations (KPs) that are susceptible to Human Immunodeficiency Virus (HIV) acquisition, transmission, and disruptions to access HIV services. This study aimed to explore and describe the HIV interventions implemented among MSM
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Men who have sex with men (MSM) are part of the key populations (KPs) that are susceptible to Human Immunodeficiency Virus (HIV) acquisition, transmission, and disruptions to access HIV services. This study aimed to explore and describe the HIV interventions implemented among MSM during the COVID-19 lockdown in the Capricorn District of Limpopo Province in South Africa. This study followed an exploratory qualitative study design with a purposive sample of 16 men who identified as MSM. Data were collected through in-depth interviews which were tape-recorded, transcribed verbatim, and captured on Atlas.ti. Patterns from the created codes were formulated into themes/sub-themes guided by the Consolidated Framework for Implementation Research (CFIR). The MSM had a mean age of 27.9 years. Various constructs and domains of the CFIR showed that during the COVID-19 lockdown, MSM encountered a disruption of HIV services. The response time was elongated, thus increasing the complexity of interventions. Interventions were implemented to ensure continuity of services. These included tailoring the programme through a door-to-door strategy and offering resources to healthcare facilities to enable MSM to access antiretroviral therapy (ART) and related services. The relative advantage of the programme is that it prioritises MSM. Future research should look into COVID-19’s impact on a bigger scale.
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(This article belongs to the Section COVID Public Health and Epidemiology)
Open AccessBrief Report
Effect of COVID-19 Infection on the Immune Response to the SARS-CoV-2 Vaccine in Rheumatoid Patients
by
Maria Jose Gallardo-Nelson, Yolanda Gómez, Javiera Del Villar and Fernanda Zapata
COVID 2025, 5(10), 179; https://doi.org/10.3390/covid5100179 - 20 Oct 2025
Abstract
Rheumatic diseases affect the musculoskeletal system and may also compromise internal organs. The immunosuppressive treatments commonly used in these conditions can weaken the immune system, raising concerns about the efficacy of immunizations, particularly against SARS-CoV-2. This observational and analytical study evaluated the humoral
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Rheumatic diseases affect the musculoskeletal system and may also compromise internal organs. The immunosuppressive treatments commonly used in these conditions can weaken the immune system, raising concerns about the efficacy of immunizations, particularly against SARS-CoV-2. This observational and analytical study evaluated the humoral immune response in patients with rheumatic diseases who were vaccinated with a fourth dose of the SARS-CoV-2 vaccine in comparison with a control group and the effect prior COVID-19 infection. The results showed that individuals with a history of COVID-19 infection developed significantly higher levels of neutralizing antibody titers, indicating a stronger immune response. Moreover, the response on the Wuhan strain elicited a more robust humoral response than the Omicron strain in both immunocompromised patients and healthy controls. These findings highlight the impact of previous viral exposure on the effectiveness of immunization in rheumatology patients.
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(This article belongs to the Section COVID Clinical Manifestations and Management)
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Open AccessArticle
COVID-19 Exposure, Susceptibility, and Treatment Among Racial and Ethnic Minorities in Pennsylvania, USA: Evidence from a Cross-Sectional, Non-Probability Web Panel Survey
by
S. Wilton Choi, Jae Man Park, Mingean Park, Timothy Servinsky, Jr. and Kyungha Kim
COVID 2025, 5(10), 178; https://doi.org/10.3390/covid5100178 - 18 Oct 2025
Abstract
This study adopted a survey instrument based on a consistent conceptual framework to investigate racial and ethnic disparities in COVID-19 exposure, susceptibility, and treatment among Pennsylvania residents. A cross-sectional design was implemented through primary data collection using a non-probability web panel. Quota sampling
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This study adopted a survey instrument based on a consistent conceptual framework to investigate racial and ethnic disparities in COVID-19 exposure, susceptibility, and treatment among Pennsylvania residents. A cross-sectional design was implemented through primary data collection using a non-probability web panel. Quota sampling ensured statewide representativeness by region and combined age/gender categories, yielding a final sample of 1043 residents across 64 counties who completed the survey between February and April 2021. Propensity score matching was utilized to estimate average effects of race/ethnicity on COVID-19-related outcomes. Results indicated that racial/ethnic minority respondents were more likely than non-Hispanic White respondents to live in apartments or group quarters. Non-Hispanic Blacks and Asians were disproportionately urban residents, while non-Hispanic Blacks faced increased COVID-19 exposure risks due to reliance on public transportation. Additionally, Non-Hispanic Others experienced higher exposure risks from insufficient sick leave and caregiving responsibilities. The study found limited evidence for disparities in susceptibility and treatment. These findings highlight how disparities in COVID-19 exposure conditions likely contribute significantly to the differing COVID-19 outcomes observed between racial/ethnic minorities and non-Hispanic Whites in Pennsylvania.
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(This article belongs to the Special Issue COVID and Public Health)
Open AccessArticle
Understanding the Association Between Long COVID, Neurological Symptoms, and Anxiety
by
Negeen Farida, Leanne Levin, Taylor Kuhn and James Vivian
COVID 2025, 5(10), 177; https://doi.org/10.3390/covid5100177 - 17 Oct 2025
Abstract
Long COVID, characterized by persistent symptoms following COVID-19 infection, poses significant challenges to individuals’ well-being. This study explores the multifaceted nature of long COVID, encompassing neurological and psychological manifestations. Neurological symptoms, including difficulty thinking clearly (brain fog) and concentrating, are prominent features of
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Long COVID, characterized by persistent symptoms following COVID-19 infection, poses significant challenges to individuals’ well-being. This study explores the multifaceted nature of long COVID, encompassing neurological and psychological manifestations. Neurological symptoms, including difficulty thinking clearly (brain fog) and concentrating, are prominent features of long COVID, drawing increasing attention due to their potential long-term adverse impact on the patient’s daily functioning and quality of life. Furthermore, anxiety emerges as a prevalent psychological concern among individuals with long COVID, exacerbating the uncertainty and distress associated with the ongoing symptoms of the virus. Despite growing recognition of the interplay between long COVID, neurological symptoms, and anxiety, there remains a notable gap in the literature regarding the specific relationship between these domains. This study addresses this gap by investigating how the presence of long COVID symptoms relates to the manifestation of neurological symptoms, with anxiety as a potential mediator. Utilizing data from the COVID-19 Health and Mental Health Survey, this research provides insights into the complex interplay between long COVID, neurological symptoms, and anxiety. This research provides a deeper understanding of the long-term implications of this virus and informs assessment and intervention for these patients.
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(This article belongs to the Section COVID Public Health and Epidemiology)
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Open AccessSystematic Review
COVID-19 and Lactoferrin: A Systematic Review and Meta-Analysis
by
Erika Palacios-Rosas, Adriana Palacios, Mariana Cuautle, Tawfiq Abdulaziz-Almughanam, Zabdi Paulina Pérez-Urquieta, Eduardo Alejandro López-López and Ana Sofía García-Montejano
COVID 2025, 5(10), 176; https://doi.org/10.3390/covid5100176 - 16 Oct 2025
Abstract
To analyze the relationship between lactoferrin and COVID-19, a systematic review and meta-analysis of works published between 2020 and 2025 was carried out. The search strategy consisted of compiling research and review articles with the keywords COVID-19 and lactoferrin, COVID-19 and lactoferrin, SARS-COV-2
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To analyze the relationship between lactoferrin and COVID-19, a systematic review and meta-analysis of works published between 2020 and 2025 was carried out. The search strategy consisted of compiling research and review articles with the keywords COVID-19 and lactoferrin, COVID-19 and lactoferrin, SARS-COV-2 and lactoferrin, and SARS-COV-2 and lactoferrin in the databases of the search engines Elsevier, PubMed, and Google Scholar. In addition, these were classified depending on the type of study (e.g., in vivo, in vitro, both, or neither). PRISMA was used to perform a systematic review and meta-analysis. A total of 1531 articles were found, of which any duplicates were discarded, leaving 1234. A second database was created for strictly research and in vivo type articles, obtaining only 69 articles. Lactoferrin demonstrated a significant effect in reducing fatigue among COVID-19 patients, contributing to improved recovery and functional status—particularly in individuals with post-acute COVID-19 syndrome. However, its impact on other symptoms did not reach statistical significance.
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(This article belongs to the Section COVID Clinical Manifestations and Management)
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Open AccessArticle
COVID-19-Related Delirium Associated with Increased Length of Stay and Mortality
by
Jerry Bradley, Fei Tang, Zachary Panzarella, Jacob Nanney, Bill Bryant, Iriana Hammel and Darby Cole
COVID 2025, 5(10), 175; https://doi.org/10.3390/covid5100175 - 16 Oct 2025
Abstract
We set out to determine the impact of delirium and COVID-19 on length of stay and mortality. For this study, we conducted a retrospective cohort study of patients aged >65 years admitted to the Owensboro Health Regional Hospital between August 2021 and December
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We set out to determine the impact of delirium and COVID-19 on length of stay and mortality. For this study, we conducted a retrospective cohort study of patients aged >65 years admitted to the Owensboro Health Regional Hospital between August 2021 and December 2023. Delirium was determined based on a score of ≥2 on the Nurse Delirium Screening Scale (NuDESC) recorded on all admitted patients three times a day during nursing shift change. Multivariate logistic regression models were used to evaluate the association between delirium, COVID-19, or both on 30-day, 60-day, 90-day, 180-day, 360-day mortality, adjusting for age, sex, race, smoking status, diabetes, hypertension, dementia, COPD, obesity, heart failure, and heart disease. A total of 4872 hospitalized patients were included in the study. Of these, 698 (14.3%) were identified as having delirium and 4174 (85.7%) as without delirium. Patients with delirium were slightly older than those without (79.5 ± 8.6 years old vs. 77.0 ± 7.9). After adjusting for comorbidities, delirium was associated with an increase of 3.3 hospitalization days (8.6 ± 9.6 days vs. 5.3 ± 5.6 p < 0.01). Delirium was associated with higher 30-day, 60-day, 90-day, 180-day, and 360-day mortality rates. COVID-19-positive patients with delirium had 717% higher odds of 30-day mortality compared to the COVID-19-negative patients without delirium (aOR 8.17 95% CL 4.60–14.3).
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(This article belongs to the Section COVID Clinical Manifestations and Management)
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