Wuhan study spotlights China’s Covid-19 herd immunity challenge
- Swift lockdown measures brought disease under control but population vulnerable to imported infections without vaccinations
- Researchers find possibly 10 times more people than original estimates could have been infected but herd immunity a long way off
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Returning to Wuhan one year since the Chinese city became ground zero of the Covid-19 pandemic
The findings, published in The Lancet medical journal on Friday, show infected people who had neutralising antibodies – thought to be crucial to the body’s defence against Covid-19 – maintained steady levels over at least a nine month period. The data is the first of its kind collected long-term in Wuhan, adding new information to the question of how long people may be protected from Covid-19 after infection.
The scientists also estimated nearly 7 per cent of Wuhan’s population had virus antibodies, a standard measure of previous Covid-19 infection, by last April. While various factors can impact such estimates, this suggests more than 600,000 of the 9 million people thought to be in Wuhan during the peak of its outbreak could have been infected – more than 10 times the 50,000 officially reported cases from the time.
Despite this, the researchers, who are affiliated with several institutions including the Wuhan Centre for Disease Control and Prevention, said their findings meant most of the population remained vulnerable to Covid-19.
“Even at the epicentre of the pandemic in China … the estimated seroprevalence in Wuhan remains low, and around 40 per cent of people with [traces of past infection] developed neutralising antibodies, suggesting there is still lack of immunity in the population,” said co-author Wang Chen of Peking Union Medical College.
China is seeking to ramp up its domestic vaccination programme, with an ambitious goal to vaccinate 40 per cent of the population – some 560 million people – by July.