The concept of herd immunity relies on widespread COVID-19 infections building population-level protection through antibodies. A preliminary Chinese study, however, suggests this approach faces significant hurdles.
As the COVID-19 pandemic unfolded, experts debated the immunity gained from infection. Some argued that recovered individuals develop protective antibodies, at least temporarily, while others warned of reinfection risks. Several countries, including the UK initially, considered herd immunity by allowing controlled virus spread to infect a large portion of the population, ultimately slowing transmission as fewer susceptible hosts remain—despite anticipated fatalities.
Reported by the Wall Street Journal on April 16, 2020, a preliminary Chinese study offers critical insights. To safely resume economic activity and avert a second wave, China launched nationwide serological testing for asymptomatic spread and immunity levels. Thousands underwent tests to gauge antibody prevalence.
Early results from Wuhan, the epicenter with 11 million residents, are concerning. Antibody development rates were far too low to support herd immunity, even amid potential thousands of undetected asymptomatic cases.
At Zhongnan Hospital, one of Wuhan's largest, tests on 3,600 staff revealed just 2.4% had antibodies. Among 5,000 recent patients and visitors, positivity ranged from 2-3%. These figures underscore that herd immunity remains elusive.
Zhongnan Hospital Director Wang Xinghuan emphasized vaccines as the primary hope, with initial candidates not expected until 2021. China's fear of a second wave persists, compounded by uncertainty over whether positive antibody tests guarantee immunity.
