Science

Less than 4% of Wuhan residents report Covid antibodies: Report

Prashasti Awasthi Mumbai | Updated on October 27, 2020 Published on October 27, 2020

Finding dampens hope of health experts who vouched for herd immunity

Fewer than 4 per cent of people in China’s Wuhan, where the coronavirus outbreak first began, had reported antibodies without contracting the coronavirus.

Also read: ‘Herd immunity’ not a strategy in an outbreak, let alone a pandemic: WHO Chief

This further dampens the hope of some health experts who vouched for herd immunity.

The new study, published on Friday in JAMA Network Open, suggested that the large population of people, who were never diagnosed with coronavirus, including those who seemed to be asymptomatic, never had it.

Or, even if they did, the antibodies needed to ward off SARS-CoV-2 have waned beyond the point of being detectable, thereby raising the chance of reinfection.

Also read: Young, healthy people may not be vaccinated for Covid-19 until 2022: WHO

When the virus, which earlier was thought to be a mysterious form of pneumonia, emerged in China, the asymptomatic infection rate was about one in five cases. Hence, it is speculated that a larger number of people were infected than the confirmed cases.

However, China undertook a massive feat in May: Every Wuhan resident over age five was tested for coronavirus.

Methodology

For the latest study, the researchers took samples from 35,000 participants in Wuhan.

Also read: China claims Covid-19 broke out in various parts of the world

The authors of the study observed two types of antibodies that help the body fight pathogens: IgM — the type of specialised immune proteins that get developed shortly after infection; and IgG antibodies — which offer lasting protection.

Findings

According to the study, around 0.7 per cent of the participants had both types of antibodies. This suggested that their immune system's long-term protection was still developing, and they had been infected some weeks prior.

Only 3.2 per cent of the tens of thousands of recruits had longer-lasting IgG antibodies alone. This means that altogether, just 3.9 per cent of the group had any antibodies.

The researchers also noted that people were more likely to have antibodies if they lived in the more urban areas of Wuhan, compared to less populous ones.

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Published on October 27, 2020
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