what protection have those recovered from Covid with a single dose of vaccine

Two articles in the prestigious magazine Science confirm the incomparable synergy two almost common events at this stage of the pandemic: have had coronavirus and received a dose of certain vaccine. The combination of these facts (which, in isolation, are much less relevant) would exceed, in terms of immunity, the administration of two doses to the “virgins” of the Covid.

Two clarifications: the data are excellent and speak of a 5-10 fold improvement in immune memory more than in the “only cured” or “only vaccinated”. Now, with nearly 100,000 Covid deaths in Argentina, it goes without saying that none of this should be interpreted as a suggestion to go out and get infected.

On the contrary, the information aims to reassure the more than 4 million recovered and to urge them, as soon as they are summoned, to get vaccinated.

As is known, human immunity is complex and multifaceted. Among the different types of antibodies, some highly cited are those that have the ability to neutralize Covid: neutralizing antibodies.

However, a second immunity plays a key role, in reinforcement, although it develops more slowly: it is the immune memory O cellular immunity, mediated by B and T lymphocytes.

Beyond the technical aspects, the interesting thing is that, until now, the various experts who Bugle he had consulted “they assumed” that immunological memory must play an important role against Covid. The articles published by Science now give this question a more complete dimension.

Both were released on June 25. In the same issue of the magazine, a short article that presents the auspicious data of these newspapers states the “brilliant evolutionary strategyMemory cells, in particular B, who are the most important to us now.

What are these lymphocytes doing? In the event of reinfection (in the case of hybrid immunity, the second infection would be stimulated by the vaccine), the memory B cells increase the production of antibodies.

But they’re doing something else, which sounds amazing. “They encode a library of antibody mutations.” That is, they create a “reserve of immunological variants», Clarifies the text.

In other words, the body displays a series of “precautionary assumptions about variants that might emerge in the future”. Logically, variants of the Covid.

The papers

The first of this work comes from experts at the Fred Hutchinson Cancer Research Center in the United States. The second is approved by various scientific institutions in England and Australia.

For the restless, the titles are “MRNA vaccination stimulates cross-variant neutralizing antibodies caused by SARS-CoV-2 infection“O”Previous SARS-CoV-2 infection rescues B and T cell responses to variants after first dose of vaccine“, Respectively (” Vaccination with mRNA increases cross-neutralizing antibodies caused by SARS-CoV-2 infection “and” Previous SARS-CoV-2 infection rescues B and T cell responses against different variants after the first dose of vaccine “).

Experts focused on very small groups of patients. In the first there are only 15 people. In the second, 51.

Consulted for the relevance of the results, Jorge quarleri, expert in virology, doctor in biochemistry and principal researcher at INBIRS-Conicet, demonstrated the weight qualitative versus quantitative cohorts.

“They didn’t do what is often stylish, which is to take plasma from patients and test if it can neutralize the virus, but they measured the cellular response, a hugely laborious and much more informative assessment because she manages to figure out the why, “he stressed.

Gamma and Delta

In the first article, it is pointed out that although the Covid sera observed (pre-vaccination) neutralized the Wuhan variant and, sporadically, the Beta (“ex” South Africa), a dose of vaccine “increased neutralization titers against all variants up to 1000 times”.

In the second study, a group of health workers, with and without a previous infection, were studied.

The conclusion was that after a dose of the vaccine, individuals who had had Covid had a increased cellular immunity, as well as effective neutralizing antibodies against Alpha and Beta variants.

And instead, “those who had not had Covid had reduced immunity against the variants“, He says.

Both studies indicate that, a) hybrid immunity is superior to that obtained with full immunization schedules in “virgin” or “naïve” Covid patients. And, b) that patients who have had the coronavirus (at least, those who have had symptoms) have a “cap”: the second dose does not increase their immunity.

Perhaps due to a question of dates, these documents do not allude to the worrying Delta variant.

However, in Argentina, one wonders if the hybrid immunity would be just as robust against this variant which appeared in India, as well as against Gamma (ex Manaus), one of the most circulating here.

The Gamma issue is not a minor one: on Wednesday, a Country Project report warned of the up to three-fold decrease in the neutralizing capacity of the antibodies produced by the Sputnik V vaccine against it.

Although the brief information provided in this report requires further study, it is evident that with a low titer of neutralizing antibodies, the role of immunological memory is central. Like a kind of “life jacket”.

Thousands of people who had Covid could positively deploy this other protection against the virus. Yes even more if they are vaccinated.

For Quarleri, a deep understanding of hybrid immunity is valuable right now: “Even the most ‘vaccine dodge’ (Beta) was mitigated by the intensity and extent of hybrid immunity. I don’t think there will be any difference against the Delta variant ”.

PS