Photo:Xinhua
A follow-up study conducted by Chinese scientists in Wuhan, Hubei Province, shows that 40 percent of the local COVID-19 patients have the neutralizing COVID-19 antibodies that can effectively last for at least nine months.
The study was made public in The Lancet on Friday, revealing the dynamic changes of serum antibodies in COVID-19 patients, which is also helpful for the evaluation of vaccine protection efficacy.
Wang Chen, the lead author of the paper and president of the Chinese Academy of Medical Sciences and Peking Union Medical College, said that assessing the proportion of immunized individuals is critical to work out effective prevention and control strategies to reduce the risk of a future epidemic.
The study is the first long-term serum epidemiology investigation conducted in Wuhan. It is also a global observation with the longest prospective follow-up serum epidemiology investigation with the most follow-up visits, Xinhua News Agency reported.
The study was jointly conducted by researchers from the Chinese Academy of Medical Sciences, Peking Union Medical College, China's CDC and Wuhan's local CDC.
After Wuhan ended its lockdown in April 2020, researchers sampled blood of 9,542 residents from 3,556 households in all the 13 districts in Wuhan, then conducted follow-up visits in June and from October to December.
The study also showed that the adjusted antibody positive rate of the population in Wuhan was 6.9 percent, indicating that only a small proportion of people in Wuhan were infected.
Previous studies have shown that the number of infections calculated by the positive rate of serum antibodies is much higher than the amount of diagnosed cases of COVID-19. The main reason is that most of the infected people are asymptomatic and patients with mild cases, and may not have been tested or sought medical treatment.
Ren Lili, co-author of the paper and a researcher at the Institute of Pathogenic Biology at the Chinese Academy of Medical Sciences and Peking Union Medical College, said the intensity of antibodies in asymptomatic patients was lower than those in confirmed patients with symptoms. The finding is valuable for precise prevention and control in the future.
Professor Richard Strugnell from Doherty Institute, Australia, commented on the research that the findings underscore the success in controlling the outbreak in Wuhan of COVID-19 at a time when testing, tracing, and treatment resources were much less developed, media reported.
Global Times