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COVID19: United Kingdom study dispels herd immunity theory

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Kroger pharmacies to offer $25 rapid COVID-19 antibody tests

The survey of 365,000 people in England showed the proportion of those testing positive for COVID-19 antibodies fell 26.5% between June 20 and September 28, suggesting "immunity is waning quite rapidly", study author Helen Ward tells the BBC.

"This is a really big challenge to the idea that herd immunity can be achieved through natural immunity", argued Helen Ward, professor of public health at Imperial College, and study co-author in comments to the Financial Times. In September, only 44 per 1,000 people were positive.

In England, so far, more than 350,000 people took an antibody test as part of the REACT-2 study.

The meaning of the drop is immunity is still uncertain with other parts of the immune system, including T-cells potentially playing a role in killing infected host cells and calling to other immune cells to help out.

"What we do know is that seasonal coronaviruses that circulate every year can reinfect people after six to 12 months and we suspect that the way the body reacts to these coronaviruses is similar".

The researchers were specifically looking for IgG antibodies in the study, and CNN notes that some other research has suggested "that other types of antibodies may persist longer than IgG does".

World Health Organization spokesman Tarik Jasarevic said that uncertainty over how long immunity would last, and the fact that most people had never had antibodies against the coronavirus in the first place, showed the need to break transmission chains.

"We don't yet know whether this will leave these people at risk of reinfection with the virus that causes Covid-19, but it is essential that everyone continues to follow guidance to reduce the risk to themselves and others", she added.

The decline was largest in people aged 75 and above compared to younger people, and also in people with suspected rather than confirmed infection, indicating that the antibody response varies by age and with the severity of illness.

Kroger announced Wednesday it will soon begin offering COVID-19 rapid antibody testing at all of its pharmacies - starting now in two states. Health and care workers, ethnic minority groups, and those living in deprived areas and large households also had the greatest burden of past infection.

The findings suggest the possibility of decreasing population immunity ahead of a second wave of infections in recent weeks that has forced local lockdowns and restrictions.

A group of worldwide experts push back against the Great Barrington Declaration and its pursuit of COVID-19 herd immunity, calling it "a risky fallacy unsupported by scientific evidence".

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