Newswise — A comprehensive analysis of antibody responses in coronavirus disease 2019 (COVID-19) patients could inform the development of an effective vaccine, according to a study published September 10 in the open-access journal PLOS Pathogens by Chao Wu and Rui Huang of Nanjing University Medical School, and colleagues. The results show that the neutralizing activity of antibodies from recovered patients is typically not strong, and declines sharply within one month after hospital discharge. 

The world is facing an unprecedented challenge with communities and economies affected by the growing COVID-19 pandemic. Currently, there is no vaccine or effective drugs approved to treat or prevent the disease. A better understanding of antibody responses against SARS-CoV-2 -- the virus that causes COVID-19 -- will provide fundamental information for developing effective treatments and a preventive vaccine. In the new study, researchers continuously monitored SARS-CoV-2-specific antibody responses in 19 non-severe and seven severe COVID-19 patients for seven weeks from disease onset. 

Most patients generated antibody responses against SARS-CoV-2, including the viral nucleoprotein and three parts of the spike protein: the receptor-binding domain, S1 protein, and ectodomain. Although 80.7% of recovered COVID-19 patients had varying levels of antibody neutralization activity against SARS-CoV-2, only a small portion of patients elicited a potent level of neutralization activity. This result highlights the importance of carefully selecting blood samples from recovered patients using antibody neutralization assays prior to transfusion into other COVID-19 patients. Three to four weeks after hospital discharge, the neutralizing activity of antibodies from recovered patients declined significantly, suggesting that recovered COVID-19 patients might be susceptible to reinfection with SARS-CoV-2. In addition, severe COVID-19 patients had a large amount of non-neutralizing antibodies, which may contribute to antibody-dependent enhancement of infection. According to the authors, the study provides important insights for serological testing, antibody-based intervention, and vaccine design.




Funding: This study was supported by the Fundamental Research Funds for the Central Universities (No. 14380459 to CW). the Medical Science and technology Development Foundation, Nanjing Department of Health (YKK19056 to YC), Nanjing Medical Science and Technique Development Foundation (QRX17141 to YC). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.


Competing Interests: The authors have declared that no competing interests exist.


About PLOS Pathogens

Pathogens is the first Open Access journal for breakthroughs in understanding pathogens and their interactions with host organisms. The journal publishes original research and commentary that yield novel insights into pathogenesis that are of broad interest and importance to researchers studying pathogens and pathogen-host interactions.  For more information, visit, and follow @PLOSPathogens on Twitter.


About the Public Library of Science
Public Library of Science (PLOS) is a nonprofit Open Access (OA) publisher, innovator and advocacy organization dedicated to accelerating progress in science and medicine by leading a transformation in research communication. The PLOS suite of journals contain rigorously peer-reviewed Open Access research articles from all areas of science and medicine, together with expert commentary and analysis. In addition to journals, the organization advances innovations in scientific publishing through Collections, Communities and The PLOS Blog Network. Founded to catalyze a revolution in scientific publishing by demonstrating the value and feasibility of Open Access publication, PLOS is committed to innovative and forward-looking solutions to scientific communication. For more information, visit


Journal Link: PLOS Pathogens