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, 302 KiB  
Article
Understanding Influencer Followership on Social Media: A Case Study of Students at a South African University
by Nkosinathi Mlambo, Mpendulo Ncayiyane, Tarirai Chani and Murimo Bethel Mutanga
Journal. Media 2025, 6(3), 120; https://doi.org/10.3390/journalmedia6030120 (registering DOI) - 29 Jul 2025
Abstract
The influence of social media personalities has grown significantly, especially among youth audiences who spend substantial time on platforms like TikTok. The emergence and popularity of different types of social media influencers accelerated during the COVID-19 pandemic in many countries, including South Africa. [...] Read more.
The influence of social media personalities has grown significantly, especially among youth audiences who spend substantial time on platforms like TikTok. The emergence and popularity of different types of social media influencers accelerated during the COVID-19 pandemic in many countries, including South Africa. In turn, this period also saw a surge in youth audiences following these influencers. This rapid growth of influencer followings among young people is largely driven by specific types of content that resonate with them, thus encouraging continued engagement. However, the benefits that these young followers gain from engaging with various influencers and the factors driving their preferences for specific influencers remain underexplored, particularly within the context of South African students within higher education. Therefore, this study explores the types of social media influencers most followed by university students at a South African University and investigates the key factors that drive their preferences. A structured online questionnaire was distributed, gathering both multiple-choice and open-ended responses from students. The data were analyzed using categorical frequency counts and thematic analysis. The data highlight how students actively turn to influencers as emotional anchors, role models, and sources of practical guidance. Their engagement reflects a deep need for connection, inspiration, and identity formation in a challenging academic and social environment. These patterns show that influencer content is not just entertainment but plays a critical developmental role. Understanding these motivations helps educators, policymakers, and brands to align better with youth values. The significance of these results lies in how influencer content is now coming in to fill the emotional, cultural, and educational gaps left by traditional systems among the young South African university students in this modern era. Full article
24 pages, 4103 KiB  
Article
SARS-CoV-2 Remdesivir Exposure Leads to Different Evolutionary Pathways That Converge in Moderate Levels of Drug Resistance
by Carlota Fernandez-Antunez, Line A. Ryberg, Kuan Wang, Long V. Pham, Lotte S. Mikkelsen, Ulrik Fahnøe, Katrine T. Hartmann, Henrik E. Jensen, Kenn Holmbeck, Jens Bukh and Santseharay Ramirez
Viruses 2025, 17(8), 1055; https://doi.org/10.3390/v17081055 (registering DOI) - 29 Jul 2025
Abstract
Various SARS-CoV-2 remdesivir resistance-associated substitutions (RAS) have been reported, but a comprehensive comparison of their resistance levels is lacking. We identified novel RAS and performed head-to-head comparisons with known RAS in Vero E6 cells. A remdesivir escape polyclonal virus exhibited a 3.6-fold increase [...] Read more.
Various SARS-CoV-2 remdesivir resistance-associated substitutions (RAS) have been reported, but a comprehensive comparison of their resistance levels is lacking. We identified novel RAS and performed head-to-head comparisons with known RAS in Vero E6 cells. A remdesivir escape polyclonal virus exhibited a 3.6-fold increase in remdesivir EC50 and mutations throughout the genome, including substitutions in nsp12 (E796D) and nsp14 (A255S). However, in reverse-genetics infectious assays, viruses harboring both these substitutions exhibited only a slight decrease in remdesivir susceptibility (1.3-fold increase in EC50). The nsp12-E796D substitution did not impair viral fitness (Vero E6 cells or Syrian hamsters) and was reported in a remdesivir-treated COVID-19 patient. In replication assays, a subgenomic replicon containing nsp12-E796D+nsp14-A255S led to a 16.1-fold increase in replication under remdesivir treatment. A comparison with known RAS showed that S759A, located in the active site of nsp12, conferred the highest remdesivir resistance (106.1-fold increase in replication). Nsp12-RAS V166A/L, V792I, E796D or C799F, all adjacent to the active site, caused intermediate resistance (2.0- to 11.5-fold), whereas N198S, D484Y, or E802D, located farther from the active site, showed no resistance (≤2.0-fold). In conclusion, our classification system, correlating replication under remdesivir treatment with RAS location in nsp12, shows that most nsp12-RAS cause moderate resistance. Full article
(This article belongs to the Special Issue Viral Resistance)
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14 pages, 564 KiB  
Article
Assessment of SARS-CoV-2 Infection, Vaccination, and Immunity Status Among a Population of Dentists/Academic Professors in a Clinical Setting: One-Year Findings
by Patricia Manarte-Monteiro, Gabriella Marques, Dina Alves, Mary Duro, Joana Domingues, Sandra Gavinha, Lígia Pereira da Silva and Liliana Teixeira
COVID 2025, 5(8), 120; https://doi.org/10.3390/covid5080120 - 28 Jul 2025
Abstract
Background: This study aimed to assess the prevalence of SARS-CoV-2 infection, vaccination, and immune status among a population, both Dentists and University Professors, within a clinical setting at one and at 12 months after COVID-19 vaccination. Methods: A cross-sectional study involving 47 professionals [...] Read more.
Background: This study aimed to assess the prevalence of SARS-CoV-2 infection, vaccination, and immune status among a population, both Dentists and University Professors, within a clinical setting at one and at 12 months after COVID-19 vaccination. Methods: A cross-sectional study involving 47 professionals (aged 27–52) was conducted in the University Fernando Pessoa. Participants completed an online survey on SARS-CoV-2 infection status and vaccination, received and provided plasma samples for serological analysis. The protocol was approved by the UFP-Ethics Committee. Anti-S1-RBD SARS-CoV-2 IgM and IgG antibody titration values (AU/mL) were measured, by enzyme-linked-immunosorbent assay (ELISA), with reactive immunoglobulins (Ig) seropositivity for values ≥1 AU/mL. Results: SARS-CoV-2 infection rate increased from 8.5% in July 2021 to 48.9% in June 2022, with 8.5% experiencing reinfection. Vaccination rate was 91.5% by July 2021 and increased slightly to 93.6% by June 2022; 72.3% of the sample received a third dose. IgG seropositivity increased from 91.5% to 95.7% in June 2022. After one-year, significant associations were found between IgG seropositivity and both participant’s age (p = 0.009; <50 years) and vaccine doses (p = 0.003; 1–3 doses) received. Conclusions: SARS-CoV-2 infection rate, vaccination, and IgG seropositivity rates were high and increased over one year. The age and vaccination status were associated with the immunity status at 12th month follow-up. Findings highlight variability in IgG seroprevalence due to multiple influencing factors, which justifies future studies. Full article
(This article belongs to the Section COVID Clinical Manifestations and Management)
14 pages, 597 KiB  
Article
Sex Disparities Among Lithuanian Ischemic Stroke Patients According to Laboratory Findings; Comorbidities, Including COVID-19; Acute In-Hospital Complications; and Outcomes
by Erika Jasukaitienė, Šarūnas Augustis, Lolita Šileikienė, Abdonas Tamošiūnas, Dalia Lukšienė, Gintarė Šakalytė, Diana Žaliaduonytė, Karolina Marcinkevičienė, Daina Krančiukaitė-Butylkinienė and Ričardas Radišauskas
Medicina 2025, 61(8), 1367; https://doi.org/10.3390/medicina61081367 - 28 Jul 2025
Abstract
Introduction. Ischemic stroke (IS) is a critical health issue, affecting individuals of all ages, sexes, and backgrounds. Mounting evidence suggests that sex indeed could play some distinct role in shaping the incidence, outcomes, and treatment of IS. In the context of the [...] Read more.
Introduction. Ischemic stroke (IS) is a critical health issue, affecting individuals of all ages, sexes, and backgrounds. Mounting evidence suggests that sex indeed could play some distinct role in shaping the incidence, outcomes, and treatment of IS. In the context of the COVID-19 pandemic, contradictory findings from previous studies that also addressed sex differences in cerebrovascular diseases demonstrate the need for further focused research. This study aimed to evaluate the sex discrepancies in the clinical presentation of IS and its outcomes in patients admitted to Kaunas Hospital of the Lithuanian University of Health Sciences (LUHS), Lithuania. Methods. This is a retrospective record-based single-center study. All the study patients—727 men and 1082 women—enrolled between January 1, 2020, and February 27, 2022; suffered from acute IS; and had absolute contraindications against interventional IS treatment. These patients received a conservative non-interventional IS treatment at the neurological department of the LUHS’s Kaunas Hospital. The sociodemographic data; laboratory findings; comorbidities, including COVID-19; in-hospital complications; and outcome factors were obtained from the patients’ medical records and evaluated by deploying appropriate statistical tests. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by the Cox proportional hazards regression for in-hospital lethality. Results. The mean age of IS patients was significantly higher in women compared to men (p < 0.001), as was the proportion of in-hospital deaths (19.10% and 15.36%, respectively; p < 0.05). The mean total number of in-hospital complications was again significantly higher in the group of women compared to men (p < 0.05). The prevalence of COVID-19 was higher in men compared to women (p < 0.05). COVID-19 diagnosis (HR = 1.53; p = 0.02) and acute in-hospital pulmonary complications (HR = 1.91; p = 0.008) significantly increased the risk of in-hospital lethality in men. The risk of in-hospital lethality was significantly higher in women with comorbid diabetes mellitus type 2 (DM) compared to those with comorbid isolated arterial hypertension (AH) (HR = 2.25, p = 0.007). Increased C-reactive protein elevated the risk of in-hospital lethality by more than twice in both men and women (HR = 2.46; p < 0.001 and HR = 2.28; p < 0.001, respectively). Conclusions. The following differences between men and women with IS were determined: Acute in-hospital pulmonary complications, including COVID-19, significantly increased the risk of in-hospital lethality in the male group, but not in women. However, women suffering from DM had a significantly increased risk of in-hospital lethality compared with those women IS patients with AH or chronic ischemic heart disease (IHD). Increased C-reactive protein was associated with an elevated risk of in-hospital lethality both in male and female groups. Full article
(This article belongs to the Section Epidemiology & Public Health)
20 pages, 1392 KiB  
Article
The Impact of COVID-19 on People Living with HIV: A Network Science Perspective
by Jared Christopher, Aiden Nelson, Paris Somerville, Simran Patel and John Matta
COVID 2025, 5(8), 119; https://doi.org/10.3390/covid5080119 - 28 Jul 2025
Abstract
People living with HIV (PLWH) faced diverse challenges during the COVID-19 pandemic, including disruptions to care, housing instability, emotional distress, and economic hardship. This study used graph-based clustering methods to analyze pandemic-era experiences of PLWH in a national sample from the NIH’s All [...] Read more.
People living with HIV (PLWH) faced diverse challenges during the COVID-19 pandemic, including disruptions to care, housing instability, emotional distress, and economic hardship. This study used graph-based clustering methods to analyze pandemic-era experiences of PLWH in a national sample from the NIH’s All of Us dataset (n = 242). Across three graph configurations we identified consistent subgroups shaped by social connectedness, housing stability, emotional well-being, and engagement with preventive behaviors. Comparison with an earlier local study of PLWH in Illinois confirmed recurring patterns of vulnerability and resilience while also revealing additional national-level subgroups not observed in the smaller sample. Subgroups with strong social or institutional ties were associated with greater emotional stability and proactive engagement with COVID-19 preventive behaviors, while those facing isolation and structural hardship exhibited elevated distress and limited engagement with COVID-19 preventive measures. These findings underscore the importance of precision public health strategies that reflect the heterogeneity of PLWH and suggest that strengthening social support networks, promoting housing stability, and leveraging institutional connections may enhance pandemic preparedness and HIV care in future public health crises. Full article
(This article belongs to the Section COVID Public Health and Epidemiology)
19 pages, 4424 KiB  
Article
Humoral and Memory B Cell Responses Following SARS-CoV-2 Infection and mRNA Vaccination
by Martina Bozhkova, Ralitsa Raycheva, Steliyan Petrov, Dobrina Dudova, Teodora Kalfova, Marianna Murdjeva, Hristo Taskov and Velizar Shivarov
Vaccines 2025, 13(8), 799; https://doi.org/10.3390/vaccines13080799 - 28 Jul 2025
Abstract
Background: Understanding the duration and quality of immune memory following SARS-CoV-2 infection and vaccination is critical for informing public health strategies and vaccine development. While waning antibody levels have raised concerns about long-term protection, the persistence of memory B cells (MBCs) and T [...] Read more.
Background: Understanding the duration and quality of immune memory following SARS-CoV-2 infection and vaccination is critical for informing public health strategies and vaccine development. While waning antibody levels have raised concerns about long-term protection, the persistence of memory B cells (MBCs) and T cells plays a vital role in sustaining immunity. Materials and Methods: We conducted a longitudinal prospective study over 12 months, enrolling 285 participants in total, either after natural infection or vaccination with BNT162b2 or mRNA-1273. Peripheral blood samples were collected at four defined time points (baseline, 1–2 months, 6–7 months, and 12–13 months after vaccination or disease onset). Immune responses were assessed through serological assays quantifying anti-RBD IgG and neutralizing antibodies, B-ELISPOT, and multiparameter flow cytometry for S1-specific memory B cells. Results: Both mRNA vaccines induced robust B cell and antibody responses, exceeding those observed after natural infection. Memory B cell frequencies peaked at 6 months and declined by 12 months, but remained above the baseline. The mRNA-1273 vaccine elicited stronger and more durable humoral and memory B-cell-mediated immunity compared to BNT162b2, likely influenced by its higher mRNA dose and longer prime-boost interval. Class-switched memory B cells and S1-specific B cells were significantly expanded in vaccine recipients. Natural infection induced more heterogeneous immune memory. Conclusions: Both mRNA vaccination and natural SARS-CoV-2 infection induce a comparable expansion of memory B cell subsets, reflecting a consistent pattern of humoral immune responses across all studied groups. These findings highlight the importance of vaccination in generating sustained immunological memory and suggest that the vaccine platform and dosage influence the magnitude and durability of immune responses against SARS-CoV-2. Full article
(This article belongs to the Special Issue Evaluating the Immune Response to RNA Vaccine)
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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 67163
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)
Current Challenges in Infectious Diseases Post COVID-19 Pandemic submission deadline 31 Jul 2025 | 3 articles | Viewed by 5091 | Submission Open
Keywords: SARS-CoV-2; COVID-19; pandemic; viral pathogens; Antibiotics
(This special issue belongs to the Section Public Health Microbiology)
COVID-19 Diagnostics in Clinical Applications, Long-Term Effect and Pandemic Controls
edited by
submission deadline 31 Jul 2025 | 2 articles | Viewed by 2709 | Submission Open
Keywords: long-term effects; COVID-19; SARS-CoV-2; pneumonia
(This special issue belongs to the Section Medical Microbiology)
SARS-CoV-2 Neutralizing Antibodies 3rd Edition
edited by Youchun Wang
submission deadline 31 Jul 2025 | 2 articles | Viewed by 2372 | Submission Open
Keywords: SARS-CoV-2; neutralizing antibodies; neutralization assays; standards; monoclonal antibodies; vaccines; viral variants
(This special issue belongs to the Section Coronaviruses)
Understanding Immune Responses to COVID-19 Vaccines
edited by
submission deadline 31 Jul 2025 | 10 articles | Viewed by 22554 | Submission Open
Keywords: variants and the short duration of protective immunity; immune responses; COVID-19 vaccines
(This special issue belongs to the Section COVID-19 Vaccines and Vaccination)
COVID-19 Complications and Co-infections
edited by Amir Sohail, and
submission deadline 31 Jul 2025 | 18 articles | Viewed by 29592 | Submission Open
Keywords: SARS-CoV-2; COVID-19; complications; co-infections; hospitalization
(This special issue belongs to the Section Coronaviruses)

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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