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

16 pages, 1214 KiB  
Article
Screening of Medicinal Herbs Identifies Cimicifuga foetida and Its Bioactive Component Caffeic Acid as SARS-CoV-2 Entry Inhibitors
by Ching-Hsuan Liu, Yu-Ting Kuo, Chien-Ju Lin, Feng-Lin Yen, Shu-Jing Wu and Liang-Tzung Lin
Viruses 2025, 17(8), 1086; https://doi.org/10.3390/v17081086 (registering DOI) - 5 Aug 2025
Abstract
The emergence of SARS-CoV-2 variants highlights the urgent need for novel therapeutic strategies, particularly entry inhibitors that could efficiently prevent viral infection. Medicinal herbs and herbal combination formulas have long been recognized for their effects in treating infectious diseases and their antiviral properties, [...] Read more.
The emergence of SARS-CoV-2 variants highlights the urgent need for novel therapeutic strategies, particularly entry inhibitors that could efficiently prevent viral infection. Medicinal herbs and herbal combination formulas have long been recognized for their effects in treating infectious diseases and their antiviral properties, thus providing abundant resources for the discovery of antiviral candidates. While many candidates have been suggested to have antiviral activity against SARS-CoV-2 infection, few have been validated for their mechanisms, including possible effects on viral entry. This study aimed to identify SARS-CoV-2 entry inhibitors from medicinal herbs and herbal formulas that are known for heat-clearing and detoxifying properties and/or antiviral activities. A SARS-CoV-2 pseudoparticle (SARS-CoV-2pp) system was used to assess mechanism-specific entry inhibition. Our results showed that the methanol extract of Anemarrhena asphodeloides rhizome, as well as the water extracts of Cimicifuga foetida rhizome, Xiao Chai Hu Tang (XCHT), and Sheng Ma Ge Gen Tang (SMGGT), have substantial inhibitory effects on the entry of SARS-CoV-2pps into host cells. Given the observation that Cimicifuga foetida exhibited the most potent inhibition and is a constituent of SMGGT, we further investigated the major compounds of the herb and identified caffeic acid as a bioactive component for blocking SARS-CoV-2pp entry. Entry inhibition of Cimicifuga foetida and caffeic acid was validated on both wild-type and the currently dominant JN.1 strain SARS-CoV-2pp systems. Moreover, caffeic acid was able to both inactivate the pseudoparticles and prevent their entry into pretreated host cells. The results support the traditional use of these herbal medicines and underscore their potential as valuable resources for identifying active compounds and developing therapeutic entry inhibitors for the management of COVID-19. Full article
(This article belongs to the Section Coronaviruses)
18 pages, 3033 KiB  
Article
Mathematical Modelling of Upper Room UVGI in UFAD Systems for Enhanced Energy Efficiency and Airborne Disease Control: Applications for COVID-19 and Tuberculosis
by Mohamad Kanaan, Eddie Gazo-Hanna and Semaan Amine
Math. Comput. Appl. 2025, 30(4), 85; https://doi.org/10.3390/mca30040085 (registering DOI) - 5 Aug 2025
Abstract
This study is the first to investigate the performance of ultraviolet germicidal irradiation (UVGI) in underfloor air distribution (UFAD) systems. A simplified mathematical model is developed to predict airborne pathogen transport and inactivation by upper room UVGI in UFAD spaces. The proposed model [...] Read more.
This study is the first to investigate the performance of ultraviolet germicidal irradiation (UVGI) in underfloor air distribution (UFAD) systems. A simplified mathematical model is developed to predict airborne pathogen transport and inactivation by upper room UVGI in UFAD spaces. The proposed model is substantiated for the SARS-CoV-2 virus as a simulated pathogen through a comprehensive computational fluid dynamics methodology validated against published experimental data of upper room UVGI and UFAD flows. Simulations show an 11% decrease in viral concentration within the upper irradiated zone when a 15 W louvered germicidal lamp is utilized. Finally, a case study on Mycobacterium tuberculosis (M. tuberculosis) bacteria is carried out using the validated simplified model to optimize the use of return air and UVGI implementation, ensuring acceptable indoor air quality and enhanced energy efficiency. Results reveal that the UFAD-UVGI system may consume up to 13.6% less energy while keeping the occupants at acceptable levels of M. tuberculosis concentration and UV irradiance when operated with 26% return air and a UVGI output of 72 W. Full article
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10 pages, 355 KiB  
Article
Mood and Anxiety in University Students During COVID-19 Isolation: A Comparative Study Between Study-Only and Study-And-Work Groups
by Gabriel de Souza Zanini, Luana Marcela Ferreira Campanhã, Ercízio Lucas Biazus, Hugo Ferrari Cardoso and Carlos Eduardo Lopes Verardi
COVID 2025, 5(8), 127; https://doi.org/10.3390/covid5080127 - 5 Aug 2025
Abstract
The COVID-19 pandemic precipitated unprecedented social isolation measures, profoundly disrupting daily life, educational routines, and mental health worldwide. University students, already susceptible to psychological distress, encountered intensified challenges under remote learning and prolonged confinement. This longitudinal study examined fluctuations in anxiety and mood [...] Read more.
The COVID-19 pandemic precipitated unprecedented social isolation measures, profoundly disrupting daily life, educational routines, and mental health worldwide. University students, already susceptible to psychological distress, encountered intensified challenges under remote learning and prolonged confinement. This longitudinal study examined fluctuations in anxiety and mood among 102 Brazilian university students during the pandemic, distinguishing between those solely engaged in academic pursuits and those simultaneously balancing work and study. Data collected via the Brunel Mood Scale and State-Trait Anxiety Inventory in April and July 2021 revealed that students exclusively focused on studies exhibited significant increases in depressive symptoms, anger, confusion, and anxiety, alongside diminished vigor. Conversely, participants who combined work and study reported reduced tension, fatigue, confusion, and overall mood disturbance, coupled with heightened vigor across the same period. Notably, women demonstrated greater vulnerability to anxiety and mood fluctuations, with socioeconomic disparities particularly pronounced among females managing dual roles, who reported lower family income. These findings suggest that occupational engagement may serve as a protective factor against psychological distress during crises, underscoring the urgent need for tailored mental health interventions and institutional support to mitigate the enduring impacts of pandemic-related adversities on the student population. Full article
(This article belongs to the Section COVID Public Health and Epidemiology)
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10 pages, 5588 KiB  
Article
Anti-Viral Activity of Conessine Against Influenza A Virus
by Won-Kyung Cho and Jin Yeul Ma
Int. J. Mol. Sci. 2025, 26(15), 7572; https://doi.org/10.3390/ijms26157572 (registering DOI) - 5 Aug 2025
Abstract
Conessine is a steroidal alkaloid found in many plants. The pharmacological efficacies of conessine on various ailments, including antiviral effects against Zika, Herpes, and Coronavirus, were reported. However, the effect of conessine on the influenza virus was still unknown. In this study, conessine [...] Read more.
Conessine is a steroidal alkaloid found in many plants. The pharmacological efficacies of conessine on various ailments, including antiviral effects against Zika, Herpes, and Coronavirus, were reported. However, the effect of conessine on the influenza virus was still unknown. In this study, conessine exhibited a strong inhibitory effect against influenza A virus (IAV) infection. We examined the effect of conessine on IAV using green fluorescent protein (GFP)-expressing Influenza A/PR8/34 and wild-type A/PR8/34. The fluorescence-activated cell sorting, fluorescence microscopy, cytopathic effect analysis, and plaque assay demonstrated that conessine significantly inhibits IAV infection. Consistently, immunofluorescence results showed that conessine strongly reduces the expression of IAV proteins. The time-of-drug-addition assay revealed that conessine could affect the viral attachment and entry into the cells upon IAV infection. Further, conessine eradicated the virus before binding to the cells in the early stage of viral infection. Our results suggest that conessine has strong anti-viral efficacy against IAV infection and could be developed as an anti-influenza viral agent. Full article
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23 pages, 313 KiB  
Article
Changing Lifestyles in Highly Urbanized Regions of Russia: Short- and Longer-Term Effects of COVID Restrictions
by Irina D. Turgel and Olga A. Chernova
Urban Sci. 2025, 9(8), 306; https://doi.org/10.3390/urbansci9080306 - 5 Aug 2025
Abstract
The restrictions on business and social activity during the COVID-19 pandemic have led to significant changes in consumption patterns worldwide. Such changes are causing structural shifts in the markets of goods and services, thus affecting regional resilience. In this article, we aim to [...] Read more.
The restrictions on business and social activity during the COVID-19 pandemic have led to significant changes in consumption patterns worldwide. Such changes are causing structural shifts in the markets of goods and services, thus affecting regional resilience. In this article, we aim to assess the changing structure of the consumption of goods and services in highly urbanized Russian regions under the impact of the COVID-19 pandemic and to analyze its effects on the lifestyle of the population. According to our results, some Russian regions demonstrate a return to previous consumption levels, while others exhibit the emergence of new dynamics. The conclusion is made that COVID restrictions have invoked a paradigm shift in consumer behavior toward investment in self-development, safety, and comfort. This observation should be taken into account when developing strategies for the recovery growth of regional economies. Full article
22 pages, 5033 KiB  
Article
Seasonal Variation of Air Purifier Effectiveness and Natural Ventilation Behavior: Implications for Sustainable Indoor Air Quality in London Nurseries
by Shuo Zhang, Didong Chen and Xiangyu Li
Sustainability 2025, 17(15), 7093; https://doi.org/10.3390/su17157093 (registering DOI) - 5 Aug 2025
Abstract
This study investigates the seasonal effectiveness of high-efficiency particulate air (HEPA) purifiers and window-opening behaviors in three London nurseries, using continuous indoor and outdoor PM2.5 monitoring, window state and air purifier use, and occupant questionnaire data collected from March 2021 to February [...] Read more.
This study investigates the seasonal effectiveness of high-efficiency particulate air (HEPA) purifiers and window-opening behaviors in three London nurseries, using continuous indoor and outdoor PM2.5 monitoring, window state and air purifier use, and occupant questionnaire data collected from March 2021 to February 2022. Of the approximately 40–50 nurseries contacted, only three agreed to participate. Results show that HEPA purifiers substantially reduced indoor particulate matter (PM2.5), with the greatest effect observed during the heating season when windows remained closed for longer periods. Seasonal and behavioral analysis indicated more frequent and longer window opening in the non-heating season (windows were open 41.5% of the time on average, compared to 34.2% during the heating season) driven by both ventilation needs and heightened COVID-19 concerns. Predictive modeling identified indoor temperature as the main driver of window opening, while carbon dioxide (CO2) had a limited effect. In addition, window opening often increased indoor PM2.5 under prevailing outdoor air quality conditions, with mean concentrations rising from 2.73 µg/m3 (closed) to 3.45 µg/m3 (open), thus reducing the apparent benefit of air purifiers. These findings underscore the complex interplay between mechanical purification and occupant-controlled ventilation, highlighting the need to adapt indoor air quality (IAQ) strategies to both seasonal and behavioral factors in educational settings. Full article
(This article belongs to the Special Issue Sustainability and Indoor Environmental Quality)
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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 67286
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)
Recent Research on Neutralizing Antibody Response to SARS-CoV-2 Variants
edited by
submission deadline 6 Aug 2025 | 2 articles | Viewed by 3521 | Submission Open
Keywords: SARS-CoV-2 and vaccines; SARS-CoV-2 and natural infection; immunity mechanism; competition between variants; SARS-CoV-2 dynamics
(This special issue belongs to the Section COVID-19 Vaccines and Vaccination)
Performance of Healthcare Systems During and After the COVID-19 Pandemic
edited by
submission deadline 30 Aug 2025 | 3 articles | Viewed by 2143 | Submission Open
Keywords: COVID-19; performance of health systems; healthcare delivery; performance indicators; health policy; decision making; healthcare management; crisis management; operations research; systems research
(This special issue belongs to the Section Health Policy)
Natural, Semisynthetic, and Synthetic Antiviral Drugs Targeting HIV and SARS-CoV-2 submission deadline 31 Aug 2025 | 4 articles | Viewed by 4511 | Submission Open
Keywords: antiviral design and discovery; natural product screening; natural products as a scaffold for semisynthetic antivirals; repurposing drugs; high-throughput screening; antiviral resistance; biophysical characterization of the interaction between antivirals and targets; combination of light and photosensitizers in antiviral discovery; cell-based and in vivo assays; in silico calculations
(This special issue belongs to the Section Viral Immunology, Vaccines, and Antivirals)
The Role of Immune Response in the Protection Against SARS-CoV-2 Infection
edited by
submission deadline 31 Aug 2025 | 1 articles | Viewed by 867 | Submission Open
Keywords: SARS-CoV-2; COVID-19; immune response; innate immune system; adaptative response; vaccines
(This special issue belongs to the Section Immunology and Immunotherapy)
How COVID-19 and Long COVID Changed Individuals and Communities 2.0 submission deadline 31 Aug 2025 | 15 articles | Viewed by 36832 | Submission Open
Keywords: individual and social attitudes and awareness toward COVID-19; literacy (scientific; medical; vaccine; health); vaccine hesitancy; compliance with screening and mitigation rules; pandemic community resilience; multifaceted responses to the enduring COVID-19 pandemic
(This special issue belongs to the Section Long COVID and Post-Acute Sequelae)

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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