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BMJ: Covid-19: Do many people have pre-existing immunity?
Do some populations have some degree of immunity from COVID-19 already? That question is answered with T-Cells, which “remember” past pathogens. It is poorly answered by antibodies, which rapidly decline over the years.
The implications of 20% to 50% prior immunity has major implications for public health policies, particularly in some countries with prior exposure to similar viruses.
BMJ: Covid-19: Do many people have pre-existing immunity?
It seemed a truth universally acknowledged that the human population had no pre-existing immunity to SARS-CoV-2, but is that actually the case? Peter Doshi explores the emerging research on immunological responses
Even in local areas that have experienced some of the greatest rises in excess deaths during the covid-19 pandemic, serological surveys since the peak indicate that at most only around a fifth of people have antibodies to SARS-CoV-2: 23% in New York, 18% in London, 11% in Madrid.123 Among the general population the numbers are substantially lower, with many national surveys reporting in single digits.
...Yet a stream of studies that have documented SARS-CoV-2 reactive T cells in people without exposure to the virus are raising questions about just how new the pandemic virus really is, with many implications... At least six studies have reported T cell reactivity against SARS-CoV-2 in 20% to 50% of people with no known exposure to the virus.
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T cell studies have received scant media attention, in contrast to research on antibodies, which seem to dominate the news (probably, says Buggert, because antibodies are easier, faster, and cheaper to study than T cells). Two recent studies reported that naturally acquired antibodies to SARS-CoV-2 begin to wane after just 2-3 months, fuelling speculation in the lay press about repeat infections.
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Could pre-existing immunity be more protective than future vaccines? Without studying the question, we won’t know.
WIND: why is there so little interest from politicians and the fear-mongering press about pressing for studies to explore this subject?
Why isn’t the science being followed, as so many “experts” insist? The policy stampede based on ignorance continues.
