Europe 1 with AFP 5:44 p.m., November 01, 2022

Pfizer on Tuesday announced positive results for newborns and infants from a clinical trial of a vaccine against respiratory syncytial virus (RSV), which causes bronchiolitis, given to mothers during pregnancy.

The vaccine has notably been shown to be around 82% effective in preventing severe cases in a baby's first three months.

The American group Pfizer announced Tuesday positive results for newborns and infants from a clinical trial on a vaccine against the respiratory syncytial virus (RSV), responsible for bronchiolitis, administered to the mother during pregnancy.

According to the results of this phase 3 test released by the company, the vaccine was found to be about 82% effective in preventing serious cases in a baby's first three months, and about 69% within six months. following.

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The trial, however, did not conclude that the vaccine reduced non-severe cases in a "statistically significant" way, even if the tests show some clinical efficacy, the laboratory indicates.

Based on these results, which have not been reviewed by independent scientists, Pfizer plans to seek authorization for the vaccine in pregnant women by the end of the year in the United States and then in other countries. country.

An epidemic that started earlier in many countries

Bronchiolitis is a common and highly contagious respiratory disease, especially in infants 2 to 8 months old, where it causes coughing and labored breathing.

Most of the time, the disease is mild.

But it may require a trip to the emergency room, or even hospitalization.

Pfizer estimates that around 102,000 children die of RSV each year worldwide, half of them under the age of six months.

Normally, the bronchiolitis epidemic starts between the end of October and mid-November, reaches a peak in December, ends at the end of January or even the end of February.

But it started this year earlier than usual in many countries.

Sanofi and Astrazeneca obtained in September a favorable opinion from the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency for nirsevimab, intended to protect infants throughout the virus circulation season.

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Monoclonal antibody

Called Beyfortus, it differs from vaccines using traditional technologies because it is a monoclonal antibody, ie an antibody developed in the laboratory, which makes it possible to confer so-called passive immunity on the infant, with a single dose.

The European Commission has yet to give the green light to its marketing.

Other pharmaceutical groups are also working on vaccines against RSV, including the British GSK and the Americans Moderna and Johnson & Johnson.

Pfizer had already announced positive results from its vaccine in the elderly in August.