Covid-19: T-cell immunity allows populations to reach herd immunity once only 10-20% are infected

Author: Share:

There is growing evidence that T-cell immunity allows populations to reach herd immunity once only 10-20% are infected with SARS-CoV-2.This would explain why a highly transmissible virus in densely populated areas peaked at 10-20% infected regardless of lockdowns or masks. 

The pervasive misconception is that we have zero immunity against COVID-19. Based on this flawed understanding, epidemiologists projected that herd immunity is not reached until 60-70% are infected. This is almost certainly wrong.

Of course, the media ignores this research While antibodies against COVID-19 may only last months, T cell immunity can remain protective for years. In a study of 23 people who survived SARS in 2003, every single one had memory T cells that recognized the SARS virus 17 years later. (Nature)

Moreover, blood samples from all 23 individuals showed “robust cross-reactivity” against SARS-CoV-2. This can be called crossover immunity.

Crossover immunity is not limited to just people who were infected with SARS years ago though.5/ In the same study, in 37 persons with no history of SARS or COVID-19 (negative serology and/or samples taken before COVID-19), over 50% had SARS-CoV-2 specific T cells.

This is not surprising because there are at least 4 strains of coronaviruses that cause the “common cold”.6/ The above study is not the only one to show this level of cross-reactivity. In a study from April 2020, in 68 healthy donors never exposed to COVID-19, 34% had T cells that reacted to SARS-CoV-2.

This finding was confirmed in yet another study published in Cell in June 2020 showing that 40-60% of unexposed individuals had T cell recognition of SARS-CoV-2. The authors hypothesized that crossover immunity came from “common cold” coronaviruses.

Crossover immunity may explain why so many young and middle-aged individuals are asymptomatic even when testing positive for coronavirus.

It is likely that their T cells recognized the virus and mounted an immune response before even mild symptoms surfaced.9/ What does this mean? All those runny noses from the common cold prepared our T cells to fight COVID-19.

Although it has been ominously called the “novel-coronavirus”, SARS-CoV-2 is yet another coronavirus with many similarities in structure to the common cold coronaviruses.10/ Why are the elderly hit so hard by COVID-19 though?

Indeed the strain of coronavirus that we faced in 2020 is more lethal than those in the past, specifically in the elderly and immunocompromised…11/ …With an understanding of T cell immunity, it makes sense that the elderly are more affected by COVID-19.

It is well known that persons in advanced age and/or who are immunocompromised lose T cells.

 Let’s get back to herd immunity via T cells. If ~50% of people had T cell immunity prior to SARS-CoV-2, then that leaves 50% of the population susceptible.

In the regions hit hardest by COVID-19, serology studies show new cases and deaths peaked at around 10-20% infected. Adding the 50% who already had T cell immunity from common cold viruses to the newly infected 10-20% equals about 60-70% immunity.

Not coincidentally, 60-70% is the percentage epidemiologists project is necessary for herd immunity with a respiratory virus. It is likely that many of the hardest hit regions of the world (e.g. Lombardy, NYC, Madrid, London, Stockholm) are now at herd immunity.

Lockdowns & mask ordinances (mostly coming after the peak) likely had little effect, with the exception of perhaps prolonging the spread.

Sweden is an example of what herd immunity looks like without lockdowns or masks. Based on serology testing, ~20% of Stockholm was infected by April. Deaths peaked in Sweden in April. Today, the pandemic is over in Sweden with zero deaths per day & subsiding new infections


Lockdown advocates will challenge this thesis and point to Indian slums and areas in Peru that reached much higher infection prevalences.

However, malnourishment is rampant in these very poor regions…And it is well known that T cell function is reduced in the malnourished. This research on T cell immunity is largely being ignored by the mainstream media, possibly due to political and pharmaceutical interests.

Hint: Assuming $35 per vaccine dose (Moderna’s price), vaccinating just the USA alone will result in a revenue of ~$10 billion annually. Considering that the coronavirus vaccine industry has the potential to be the biggest profit maker big pharma has ever seen, it is not surprising that we are seeing an overly aggressive push for lockdowns and masks until there is a vaccine—no matter the cost.

 Special thanks to the efforts of @dockaurG@ProfKarolSikora@FatEmperor, Dr. Beda Stadler (former director of the Institute for Immunology at the University of Bern) and many others who have been talking about T cell immunity for quite some time now.

Source : Tweet thread by
James Todaro
Medical Degree, Columbia University. COVID-19 research

Previous Article

కేసీఆర్ దౌర్జన్యాలను ప్రజల్లో ఎండగడుతాం: వివేక్ వెంకటస్వామి

Next Article

Did you know: The world’s tallest Ganesha statue (Bronze) is not in India

You may also like

Leave a Reply

Your email address will not be published. Required fields are marked *

7 + 5 =