Coronavirus: Greater reduction in efficacy for single-dose Johnson & Johnson than for mRNAs

A new US study shows that while vaccination remains effective against the possibility of coronavirus infection and even more so against severe Covid-19 and death, protection has declined since the Delta variant, particularly the Johnson monoclonal vaccine. & Johnson.

The researchers, led by Dr. Arthur Wallace of the Veterans Medical Center and the University of California, San Francisco, and Dr. Barbara Cohn of the U.S. Institute of Public Health, published their findings in the journal Science. adults between February and October 2021. It was found that during this time the average protection of mRNA vaccines (Pfizer / BioNTech and Moderna) against coronavirus infection had decreased from 88% to 48%.

The reduction in protection against infection was greater for the Johnson & Johnson vaccine (from 86.4% in March to only 13.1% in September), while the corresponding reductions were from 86.9% to 43.3% for Pfizer / BioNTech vaccine and from 89.2% to 58% for that of Moderna. The new study is the first to show, at a time when the coronavirus delta strain is now predominant, the long-term decline in protection against infection by the single-dose J&J vaccine, compared with the two-dose mRNAs.

On the other hand, all three vaccines (especially the two-dose vaccines) continue to provide high protection against severe Covid-19 and the risk of death, especially in people up to 65 years of age and over 65 years of age. years the benefit of vaccines remains great. Compared to those who are not vaccinated, as the new study confirms, those who are vaccinated have a much lower risk of dying from coronavirus, while those who are not vaccinated have a higher risk of infection (of any severity), serious illness and death.

In detail, among those diagnosed with a coronavirus-positive molecular test after July 1, the average efficacy of the three vaccines against the risk of death from Covid-19 was estimated at 81.7% in October. Per vaccine, mortality was estimated at 84.3% for the Pfizer / BioNTech vaccine, 81.5% for Moderna and 73% for Johnson & Johnson.

For those over 65, respectively, the efficacy against death was 71.6% for the three vaccines in general, while for each vaccine it was 75.5% for Moderna, 70.1% for Pfizer / BioNTech and 52, 2% for the exclusive J&J. Therefore, based on the above percentages, the Pfizer / BioNTech vaccine seems somewhat more effective in people up to 65 years of age, while that of Moderna is superior to those over 65 years of age. In all age groups, the J&J vaccine appears to provide lower protection than the two mRNA vaccines, which advocates boosting the dose.

“Our findings confirm that Covid-19 vaccines remain the most important tool in preventing Covid-19 infection and death. But they must be accompanied by additional measures for both vaccinated and unvaccinated people.” , such as mask use, hand washing and keeping distance. ”

“The study gives researchers, policymakers and others a strong basis for making informed decisions about vaccinations, booster doses and other safeguards, such as mask enforcement, compliance,” she said. “Physical distance testing and other public health interventions to reduce the chance of the virus spreading. For example, the CDC recommendation for booster doses to anyone who has had a Johnson & Johnson vaccine is supported by our findings.”

The Food and Drug Administration (FDA) and the US Centers for Disease Control and Prevention (CDC) have advocated “mixing” vaccines, that is, allowing a person to choose any of the three vaccines for the booster dose, regardless of which he had originally done.

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