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This is phase IV. The first data on the Pfizer-BioNTech vaccine have appeared in Israel

In Israel, for the first time, the ability of the Pfizer-BioNTech anticoid vaccine to induce an immune response was evaluated three weeks after the first dose, that is, before the fixing (second) injection. The results for the population at high risk of catching the coronavirus – for medical professionals – are published as a preprint (not yet peer reviewed report) on medRxiv.


For a year of the pandemic, it is known that SARS-CoV-2 disproportionately affects different ethnic minorities for reasons that are not yet fully clear and not fully driven by socio-demographic factors. Therefore, clarification of the immunogenicity of vaccines in a heterogeneous population is an important point. In the large Ziv medical center in Safed, there are Jews, Arabs, Druze and others of different ages. Among the staff who were offered the vaccine, as of January 21, about 90% were vaccinated.

Of the 1378 people vaccinated with the first dose, 514 took part in the study: they measured the level of neutralizing antibodies before and on the 21st day after vaccination.

See also: Do ​​you need to be vaccinated against COVID-19 if you have already been ill: explains the Deputy Minister of Health

Among those who received the vaccine, 385 were tested for levels of IgG antibodies to coronavirus prior to vaccination. Of these, six were positive for covid for IgG, another 11 were positive for PCR, but negative for IgG.

Among all vaccinated 475 (92%) were with detectable antibodies against the S-protein of the virus.

The authors write that the immunogenicity of the vaccine was similar in gender and ethnicity, but declined slightly with age.

Those who have previously had a COVID-19 infection, after the first dose, antibody levels rose at least 10 times compared to vaccinated non-sick people – regardless of whether IgG was detected before vaccination. That is, the first dose for such became a kind of reinforcing / fixing (as the second – for non-painful).

Read also: What are the side effects of the Pfizer-BNT and Moderna vaccines. Data appeared after 22 million doses injected

“Although this number is small, our data show that age and ethnicity may be associated with the likelihood of a lack of immune response. Larger data should be analyzed to confirm or refute this possibility,” the authors emphasized.

Despite the small cohort, the researchers write, the data supports: a rapid drop in IgG antibodies shortly after the acute phase of COVID-19 does not lead to loss of immunity… Mediated by the B cells of immune memory, it persists regardless of these IgG levels. In general, the authors emphasize, immune memory is retained for at least six months after an illness – and more.

Based on this, the authors point out: if there is a shortage of vaccines, then most of those who have been ill can be vaccinated later than the rest – regardless of IgG levels.

Read also: –80 ° C. How Pfizer will be vaccinated in Ukraine – scheme from Lyashko

“Nevertheless, the effectiveness of the immunity of those who have recovered from reinfection is not 100%, and the offer of vaccination to these people can provide additional protection,” added the doctors. The optimal time between illness and vaccination “remains to be determined,” they concluded.

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