Tag Archives: T-cell immunity

A “Novel” Breakthrough? New Studies Show Memory T-Cells Offer Long Term And Pre-Existing COVID Immunity, by Tyler Durden

This probably explains why Covid-19 infection rates never get much above 20 percent–a large part of the population is already immune. From Tyler Durden at zerohedge.com:

Much of the talk about the coronavirus over the last couple of months has been about antibodies.

They are looked at as part of the key to unlocking questions about immunity to the virus. Specifically, researchers have looked at how vaccines induce antibody responses and how long antibody protections last after someone has had the virus. In the answers to those questions lies the answer to another: how and when will we achieve herd immunity?

There had been worries about coronavirus antibodies over the past few months, as several studies showed they may only last several months. This had led to a litany of questions about how often one would require a vaccination and whether or not we would ever become immune to the “novel” virus.

But on Friday, a new study highlighted by Business Insider shifted focus away from antibodies and onto memory T cells – the cells that identify and destroy infected cells and inform B cells how to craft antibodies. 

The study, published in Cell, now suggests that everyone who gets COVID-19 develops T cells that may offer long term immunity by hunting down the coronavirus at later dates. “Memory T cells will likely prove critical for long-term immune protection against COVID-19,” the study says.

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Herd Immunity, by Dr. James Todaro

Because of T-cell immunity, it may only take 10 to 20 percent of a population to be infected with Covid-19 before herd immunity is reach. From Dr. James Todaro at theburningplatform.com:

1/ 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.

2/ 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

3/ 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)

4/ 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.

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