Janssen booster dose reduces omicron hospitalization, study says

A booster dose of Janssen’s Covid-19 vaccine was 84% ​​effective in preventing hospitalizations for South African healthcare workers who were infected during the spread of the omicron variant, researchers said on Thursday (30).

The empirical study, which has not yet been reviewed by the scientific community, was based on a second dose of Janssen’s vaccine administered to 69,092 practitioners between November 15th and December 20th.

An initial single-dose inoculation regimen has been shown to offer very little protection against omicron, which is rapidly proliferating in many countries after being identified in late November in southern Africa and Hong Kong.

But several studies suggest that a booster dose offers considerable protection against serious illnesses caused by the variant.

The South African study indicated that the drugmaker’s vaccine effectiveness in preventing hospitalizations rose from 63% shortly after a booster was given to 84% after 14 days. Effectiveness reached 85% between one and two months after the booster.

“This confirms for us that Covid-19 vaccines continue to be effective for the purpose for which they were created, which is to protect people from serious illness and death,” said Linda-Gail Bekker, one of the study’s researchers.

“This is yet another indication that we haven’t lost that impact, even in the face of a variant that has undergone a lot of mutation.”

Bekker said there is still no decision on additional Janssen booster vaccines.

“What we’re showing is that two doses really do restore full protection, and I don’t think we can infer from this that we’re going to need a third or fourth booster.”

Researchers said their analysis had several limitations, such as short follow-up periods, which averaged eight days for caregivers who had received the booster in the previous 13 days, or 32 days for those who had received the booster between one and two months rather, which can distort the overall effectiveness of the vaccine.

Another study conducted in South Africa this month showed that a first round of inoculation with two doses of Pfizer-BioNTech’s Covid-19 vaccine was less effective in the country at keeping people infected with the virus out of hospital since the omicron variant emerged. .