How long does it take for each vaccine to build immunity against COVID-19?

As countries move forward in vaccinating their populations, and the delta variant of the coronavirus threatens to undermine acquired immunity, new doubts arise as to the protection afforded by emergency vaccines authorized under the pandemic.

It is as if it were a light that goes out at the end of the tunnel, those who have seen vaccination as the beginning of the end of the coronavirus pandemic, mutations from SARS-CoV-2 generate a series of new questions to answer.

How long is immunity obtained? How many days after being vaccinated is a person protected?

It should be noted that each of the vaccines used has its period necessary to achieve complete immunity. For example, from what is known so far, the formulation developed by the Pfizer / BioNTech laboratory is the fastest of all vaccines requiring two doses, since seven days after receiving the second dose the person will be immune.

Thus, complete immunity will depend on the vaccine administered and the timelines established for immunization.

AstraZeneca

Efficacy in participants without evidence of previous SARS-CoV-2 infection and with an interval between doses of 10 to 12 weeks, preferably 12 weeks, from 15 days after the second dose is about 80%. That is to say, the greatest efficacy of the vaccine – 80% – would be reached 15 days after the second doseThus, between the 10-12 weeks of waiting between the first and the second, plus the 15 days, immunity with AstraZeneca would be reached approximately 111 days from the first dose.

Sputnik V

An overall analysis of the immune response induced by the Sputnik V vaccine, in which 288 individuals participated, indicated that 94% showed the presence of specific antibodies after receiving a single dose. Likewise, the study found that 96% of people under 60 have antibodies 21 days after the first application. Among the elderly, this rate is 89%. And two vaccinations generate antibodies in 100% of those vaccinated, according to the conclusion of the first stage of a longitudinal study by the Serological Studies Platform of the Province of Buenos Aires.

Para llegar a esos resultados, los investigadores tomaron muestras de plasma de los voluntarios del personal de salud del subsector public de la Provincia de Buenos Aires antes de la vacunación (basal level), a los 21 días de la primera dosis ya los 21 días de the second.

Sinopharm

The COVID-19 vaccine made in China by Sinopharm, It offers 65% protection in people under the age of 60 to prevent severe symptoms and complications from coronavirus infection. The data was made public based on reports the lab presented to the World Health Organization (WHO) Advisory Committee on Immunizations, before the agency approved the vaccine.

Regarding vaccine efficacy, preliminary results from phase III indicated that offers 79.34% protection starting 14 days after receiving both doses.

Some of the others authorized who so far do not arrive in Argentina

Pfizer / BioNTech

It is the fastest of all to gain immunity after receiving the second dose, 21 days after the first. Therefore, after the 21 days between the first and the second dose, it will take another seven days to achieve full immunity against said vaccine. In total 28 days. Efficacy in participants with or without evidence of a previous SARS-CoV-2 infection during this time period was 94.6%.

Modern

Immunity in participants with or without evidence of a previous infection with SARS-CoV-2 would be achieved 14 days after the second dose. Immunity is 93.6% and the recommended interval between the first and second dose is 28 days, so that 42 days after the first dose the person would be immune.

However, several studies have shown that the first dose already offers high protection against serious illness caused by COVID-19.

Janssen (Johnson & Johnson)

It is the only one of all vaccines that requires only one dose. In participants without evidence of previous SARS-CoV-2 infection, starting 14 days after administration, an efficacy of 66.9% was observed. In people 65 years of age or older, the effectiveness was 82.4%, while in those 75 years or older, the effectiveness was 100% and between 18 and 64 years old it was 64.2%.

Efficacy against severe illness due to COVID-19 was 76.7% at 14 days after vaccination and 85.4% at 28 days after vaccination. According to these data, immunity to Janssen would be reached at 14 doses upon receipt.

Thus, a scientific study published at the end of June reports that Pfizer and Moderna vaccines trigger immune response that can protect against COVID-19 for years, which would delay the need for booster doses.

“This is a good sign of how long this vaccine has immunity,” said Ali Ellebedy, an immunologist at Washington University in St. Louis who led the study, published in the journal Nature. Speaking to the New York Times, the scientist said the research had only looked at formulas using messenger RNA technology, but added that he expects the immune response from these vaccines is more important.

In this way, the study suggests that the vast majority of people vaccinated with mRNA technology will be protected in the long term, at least against existing variants of the coronavirusAlthough the elderly, people with weakened immune systems, and those taking drugs that suppress immunity may need boosters. For their part, people who have had COVID-19 and were subsequently vaccinated may never need a booster dose.

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