A study analyzed theeffectiveness by Pfizer-BioNTech, Moderna and Johnson & Johnson six months after the end of the vaccination cycle: the results, vaccine by vaccine
Since the Delta variant became predominant six months after the end of the Covid la vaccination cycle vaccine protection from infection drops dramatically
, in particular with regard to the single-dose Johnson & Johnson. This was stated in a research conducted by the Public Health Institute of Oakland, the Veterans Affairs Medical Center of San Francisco and the University of Texas Health Science Center recently published in Science.
The team of researchers analyzed theefficacy of the three vaccines approved in the United States (Pfizer-BioNTech, Moderna and Johnson & Johnson, absent AstraZeneca which in the United States was not approved) in protecting against contagion, disease and death i US Army veterans (representing 2.7% of the US population). The survey was conducted between 1 February and 1 October 2021 on 780,225 veterans (of which 498,148 fully vaccinated).
Protection in March 2021 and September 2021
The researchers found that early March, while the Delta variant was gaining momentum in the United States, the three vaccines were roughly equal in their ability to prevent infections. In particular, it emerged that in the March 202
1
protection from infection was
86.4% for those vaccinated with J&J
86.9% for those vaccinated with Pfizer-BioNtech
89.2% for those vaccinated with Modern
But the situation completely changed within six months, that is when the variant became the dominant strain.
In September 2021 in fact theefficacy regarding infection had dropped to
L
13.1% for those vaccinated with J&J
43.3% for those vaccinated with Pfizer-BioNTech
58% for vaccinated cin Modern
It is surprising that the Johnson & Johnson single-dose vaccine has so marked a decline in protection against infection. Germany, one of the most affected states in Europe by the new wave of Covid, is Robert Koch Institute reported that about 26% of patients fully vaccinated, with a number rising to 34% for hospitalized over 60s. The Institute also announced that infections among vaccinated people are more common in percentage terms among those vaccinated with the single-dose preparation Janssen.
In Italy (where this vaccine has been administered to 1.6 million people) the new guidelines indicate that those who have been vaccinated with Johnson & Johnson can booster immediately (regardless of age) as long as they are six months have passed since the administration of the single-dose and receive a recall with Pfizer or Moderna. In the United States, the Food and Drug Administration has cleared for J&J, recommending it to all people 18 and older who received the first dose at least two months earlier.
The protection from death remains high
In the same Science study the researchers also looked at the protection of vaccines from death from Covid and unlike the risk of infection, the effectiveness against deaths caused by Covid-19 has remained high over time and, as already demonstrated in many other studies, vaccinated people have a much lower risk of death after contracting the virus than unvaccinated, even months after vaccination, although differences in age and type of vaccine have emerged.
Eight months after the complete vaccination course, the average protection rate was 81.7% in the under 65s and 71.6% in the over 65s. Under the age of 65, the efficacy for Covid death vaccine was 73% for J&J, 81.5% for Moderna and 84.3% for Pfizer-BioNtech. In the over 65s, the protection was 52.2% for J&J, 75.5% for Moderna and 70.1% for Pfizer-BioNTech. Despite the increased risk of infection due to the Delta variant, efficacy against death remained high and, compared with unvaccinated, fully vaccinated veterans had a much lower risk of dying after infection, the researchers wrote that encourage the third dose for the entire population to block the circulation of the virus, as well as the use of masks, hand washing and spacing to reduce infection rates.
November 13, 2021 (change November 13, 2021 | 16:07)
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