Nearly 5,00,000 residents in the Chinese city Wuhan, where the novel coronavirus first emerged, may have been infected with COVID-19 — nearly 10 times its official number of confirmed cases, according to a study by the Chinese Center for Disease Control and Prevention (CDC).
The study by the agency used a sample of 34,000 people in the general population in Wuhan and other cities in Hubei province, as well as Beijing, Shanghai, and the provinces of Guangdong, Jiangsu, Sichuan and Liaoning to estimate COVID-19 infection rates, CNN reported.
It aimed to estimate the scale of past infections in a population by testing blood serum samples from a pool of people for coronavirus antibodies.
The study was conducted in April – a month after China “contained the first wave of the COVID-19 epidemic” – and the results were released Monday, according to CNN.
About 4.4% of those tested in Wuhan were found to have specific antibodies that are capable of fighting the virus.
The prevalence rate outside of Wuhan is significantly lower, the study showed. In other cities in Hubei, the province that includes the capital city, only 0.44% of residents studied were found to have the antibodies.
Outside Hubei, antibodies were only detected in two people among the more than 12,000 residents surveyed.
The study comes ahead of a visit by a team of international scientists to Wuhan to investigate the origins of the virus.
China had earlier this year been criticized internationally for its initial handling of the outbreak, which has spread around the world in a global pandemic. A number of revisions of the case and deaths data added to suspicions China was messing with the numbers.
The results for Wuhan mean even China’s worst-hit city is still vulnerable to Covid-19. Epidemiologists say at least half a population needs to have come into contact with the virus for even the minimum threshold for herd immunity.
But the city’s rate of infection is generally in line with those found in other countries after the first wave of coronavirus infections, the China CDC said in a press release published on its website, reported Indian Express.