Coronavirus: J & J’s vaccine booster increases antibody level, according to studies – archyde

by Julie Steenhuysen

CHICAGO (Reuters) – Booster dose of COVID-19 vaccine from Janssen, a subsidiary of Johnson & Johnson (J&J), sharply increases the immune response of those vaccinated, according to preliminary data from two trials to assess possible relevance such a vaccine booster.

According to these studies conducted by the American laboratory and having benefited from American federal funding, a booster of this vaccine which requires only one injection “generates a rapid and sustained increase in the levels of antibodies directed against the Spike protein (of the SARS-coronavirus). CoV-2), nine times higher than that observed 28 days after administration of this single-dose vaccine, “J&J explains in a press release.

“We had already established that an injection of our vaccine against COVID-19 triggers a strong and lasting immune response, which persists for at least eight months. With these new data, we also see that a vaccine booster further increases the levels of d ‘specific antibodies in participants who have already been vaccinated,’ explains Dr Mathai Mammen, who heads global R&D at Janssen, the pharmaceutical division of J&J.

Despite opposition from the World Health Organization (WHO), which considers it necessary to increase vaccination coverage in the first place in developing countries, several rich countries, including the United States and Israel, have already started campaigns booster vaccines to try to stem the epidemic outbreaks associated with the highly contagious Delta variant.

France plans to do the same for the elderly and frail from the start of the school year, but the High Authority for Health (HAS) recommends using only mRNA vaccines for this campaign (i.e. the vaccines from Pfizer and BioNTech d. ‘on the one hand, and Moderna on the other hand), more effective against this variant first discovered in India.

Initially considered promising, especially for vaccination campaigns in developing countries, due to its characteristics (single dose, storage conditions less restrictive than for mRNA vaccines), Janssen’s anti-COVID vaccine has been largely abandoned in Europe. and in the United States, due to its rare but potentially serious side effects (atypical blood clots, Guillain-Barré syndrome).

The American and European health authorities have repeatedly reaffirmed the favorable risk-benefit balance of this vaccine and the populations likely to receive it have been restricted in order to limit the risks.

In France, Janssen’s anti-COVID vaccine is reserved in France for people over 55 years of age.

(Report Julie Steenhuysen, French version Diana Mandiá and Myriam Rivet, edited by Bertrand Boucey)