Scientists estimate one-fifth of Americans caught coronavirus by March – dpa international

dpa

DUBLIN — Almost 20 per cent of Americans had likely caught the coronavirus by March this year, more than double the roughly 29 million officially reported by that time, according to research published on Monday by the National Academy of Sciences.

A “statistical framework” put together by University of Washington scientists suggests around 65 million Americans  caught the virus by March 7.

The team said they aimed to “provide a clear picture of Covid-19’s prevalence” as “access to tests, and a willingness to be tested, vary by location.”

Official data for Sunday show around 34.3 million cases in the US, where 608,403 people have died after catching the virus, according to the Centers for Disease Control and Prevention.

An undercount of infections could mean the virus is less deadly than official numbers suggest, as the real infection-fatality rate widens substantially beyond the official case-fatality rate, or ratio between confirmed deaths and confirmed cases.

There have been several attempts at gauging the real spread of the virus, with the World Health Organization (WHO) estimating almost a year ago that around 700 million people worldwide could have been infected by then, the majority unaware as they had not been tested or did not exhibit symptoms of Covid-19, the respiratory disease caused by the virus.

In India, a deadly recent virus surge has seen the official number of cases almost catch the US’s. The real number is likely far higher as the number of tests carried out among its 1.3 billion people  falls short of the 480 million administered among 330 million Americans.

India’s official pandemic death toll is also likely a vast undercount, the US-based Center for Global Development said last week.

Globally, around 2 per cent of confirmed cases prove fatal, according to official numbers collated by the University of Oxford’s Our World in Data. However the percentage varies wildly between countries and a clear overall picture remains elusive due to disparities in reporting criteria within and between jurisdictions, with some including deaths attributed to reasons other than the virus and others missing virus-caused deaths due to shoddy health care systems.
Antibody testing has been undertaken in various places as part of attempts to figure out the real spread of the virus, with results varying widely.
And even though the real infection numbers are likely far higher than what has been officially confirmed, they at the same time show, the University of Washington scientists said, the challenges involved reaching so-called ‘herd immunity.’
Around three-quarters of a population likely needs to have acquired virus antibodies, which are usually present after infection or vaccination, for herd immunity to be reached.
Most countries sought to slow the spread of the virus by imposing restrictions, including harsh months-long curbs on social and economic activity.
Some scientists have in turn queried the impact of the curbs, however. Stanford University researchers compared restrictions across 10 jurisdictions in a paper published in early 2021 and reported no “no clear, significant beneficial effect of [more restrictive measures] on case growth in any country.”
Some countries, such as France and Ireland, are moving to regimes where unvaccinated people are denied access to indoor dining or public transport.
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