A small study of the important National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health Usa, directed by Anthony Fauci, found that T lymphocytes recognize recent variants di SARS-CoV-2.
What are T lymphocytes
It would be a further step to understand how long our immune memory resists against a previous coronavirus infection or how long the immune system’s responses can last after a vaccination. T cells are a component of the immune system as are antibodies. They constitute the first line of defense that manages the attack of viruses and their task is to tell other cell populations, the B cells, to act as antibodies. There are many types of T cells, usually some of them solve the problem of external viruses by killing the infected cell. T cells recognize different pieces of the virus than classical antibodies (which we measure with serological tests) and are just as critical to memory for infection, they may even be a better indicator than antibodies, because some studies have shown that about twice as many people have developed T-cell immunity compared to those of which we are able to detect classical antibodies with serological tests.
Research
The team of the Institute led by Dr. Fauci analyzed blood cell samples from 30 people who had contracted Covid before the appearance of the three most widespread (and worrying) variants of the virus (WHO the article on its diffusion in Italy) and found that a key player in the immune response to SARS-CoV-2, the CD8 + T cell, remained active against the three variants. Responses mediated by specific CD8 + T cells remained largely intact and could recognize virtually all mutations in the variants studied. Although larger studies are needed, the researchers comment by stating that the T-cell response in convalescent individuals, and most likely vaccinated individuals as well, is not greatly affected by the mutations found in these three variants and should offer good protection against the same variants.
How long we will be protected
This is not to say that reinfections are not possible, but that they are difficult. Optimal immunity to SARS-Cov-2 probably requires strong multivalent T cell responses in addition to neutralizing antibodies, and each individual also responds differently depending on the type of Covid infection they have experienced (serious or mild). Currently the only test that measures the persistence of immune response available is the serological test (see sheet WHO), but it does not offer a complete overview of our immunity, which is varied. T-cell tests are more complicated and sophisticated and require complex technology, but they can be done (we talked about them WHO).
The answer to one of the most important questions is how long we will be protected after healing is not yet clearly defined (we talked about it WHO), although there are some assumptions about certain time windows. With this study we have the perspective that the protection (whatever duration it has) also extends to the variants.
April 1, 2021 (change April 1, 2021 | 19:23)
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