International Conference and Expo on

Clinical Microbiology

June 17-18, 2022 | Online Event

ICCM 2022

Interpretation of non-responders to SARS CoV 2 vaccines using WHO International Standard

Speaker at Clinical Microbiology 2022 - Xu Yang
Shanghai University of Medicine and Health Sciences, China
Title : Interpretation of non-responders to SARS CoV 2 vaccines using WHO International Standard


Coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared a pandemic. Questions about non-responders to SARS-CoV-2 vaccines remain unaddressed. Here, we report data from people after administering the complete dose of SARS-CoV-2 vaccines using the World Health Organization International Standard for anti-SARS-CoV-2 immunoglobulin (Ig). Our study showed that immune cells such as CD4 cells, CD8 cells, and B cells and anti-spike IgG levels were significantly reduced in the elderly (60 years and older). There were 7.5% of non-responders in the age group of 18 to 59 years and 11.7% in the age group of 60 years and older. An individual with a titer of anti-SARS-CoV-2 spike IgG that is below 50 BAU/mL is considered a non-responder at 30 to 90 days after the last vaccine dose. Booster vaccination may be recommended for non-responders to reduce disease severity and mortality. There are several potential strategies that are suggested to quickly end the COVID-19 pandemic: (1) increase the vaccination rate of the population; (2) develop vaccines against emerging and potential variants; (3) administer booster vaccines for non-responders; (4) accelerate clinical trials of intranasal SARS-CoV-2 vaccines to prevent transmission; (5) assessment of humoral immune response in children, the elderly, and immunocompromised individuals within 1 to 3 months after administering the fourth dose; and (6) incorporate additional protective measures for individuals with persistent (fourth or fifth dose) negative humoral immune response after booster vaccination, such as injection of anti-SARS-CoV-2 immunoglobulins, antiviral drug treatment, and use of N95 masks in endemic areas.


Dr. Xu has been a full professor at Shanghai University of Medicine and Health Sciences for several years. He has contributed to many areas of clinical immunological research, including early detection of SARS fingerprint using immune-mass-spectrometry in 2003, special diagnosis in early stage of cancer, COVID-19 severity and mortality associated with the decrease in CD4, CD8 and B cells. He is the inventor of “a method for detection of severe COVID-19 caused by co-infection with influenza A and B viruses”. He received his PhD from the Cornell University. He is the Secretary General of Global Immunity Surveillance Alliance & a national expert in China and recipient of numerous awards and honors.