The one-dose vaccine and its booster from the US laboratory Johnson & Johnson (J&J) remains 85% effective against severe cases of infection in South Africa where the Omicron variant is ultra-dominant, according to an unpaired study published Thursday.
“The effectiveness of the vaccine against hospitalizations increases after the injection of the booster dose,” reaching 85% one to two months after the second injection, according to the study published on the pre-publication site medRxiv.
The study conducted by the South African Medical Research Council (SAMRC) was conducted on healthcare workers from November 15 to December 20. Almost half a million South African caregivers have received J&J vaccines in clinical trials.
Omicron behind almost all new cases in South Africa
The variant, which has an unusually high number of mutations, is responsible for almost all new cases in South Africa, where it was detected in November. Highly contagious, its resistance to vaccines is one of the main concerns.
“The effectiveness of the anti-Covid vaccine from Johnson & Johnson remains strong and stable over time, including against circulating variants such as Omicron and Delta”, confirmed the American laboratory in a press release in view of the results of the study .
African country officially the most affected, South Africa has more than 3.4 million cases and 90,000 deaths.
Earlier in December, another South African study showed that the vaccine from the American laboratory Pfizer is overall less effective against Omicron but protects 70% against severe cases.