Johannesburg: Johnson & Johnson has announced that new preliminary results from a South African study has shown that the homologous booster shot of the company’s Covid-19 vaccine (Ad26.COV2.S) demonstrated 85 per cent effectiveness against the virus-related hospitalisation in South Africa after Omicron became the dominant variant.
The South African Phase 3b Sisonke study, conducted by the South African Medical Research Council (SAMRC), showed that the Johnson & Johnson booster reduced the risk of hospitalisation from Covid-19 among healthcare workers in the country.
“The data showing the effectiveness of the Ad26.COV.2 vaccine booster against Omicron in Sisonke is important, as this vaccine is part of our arsenal to combat Covid-19,” Nicholas Crisp, the Deputy Director General of the South African National Department of Health, said in a statement.
A second, separate analysis of the immune response to different vaccine regimens, conducted by Beth Israel Deaconess Medical Center (BIDMC), demonstrated that a heterologous booster (different vaccine) of the Johnson & Johnson Covid-19 vaccine in individuals who initially received the BNT162b2 mRNA vaccine generated a 41-fold increase in neutralising antibody responses by four weeks following the boost and a 5-fold increase in CD8+ T-cells to Omicron by two weeks.
A homologous boost with BNT162b2 generated a 17-fold increase in neutralising antibodies by four weeks following the boost and a 1.4-fold increase in CD8+ T-cells by two weeks.
“Data from the Sisonke 2 study confirm that the Johnson & Johnson Covid-19 booster shot provides 85 per cent effectiveness against hospitalisation in areas where Omicron is dominant,” said Mathai Mammen, M.D., Ph.D., Global Head, Janssen Research & Development, LLC, Johnson & Johnson.
The data have been submitted to the pre-print server medRxiv by the studies’ authors, with anticipation of publication in peer-reviewed journals.
Data from the Sisonke 2 trial, which included 227,310 healthcare workers in South Africa who received the single-shot Johnson & Johnson Covid-19 vaccine as a primary dose, show that the Johnson & Johnson Covid-19 booster increased vaccine effectiveness (VE) against hospitalization to 85 per cent.
When a booster shot was administered six to nine months after a primary single dose, VE increased over time from 63 per cent at 0-13 days, to 84 per cent at 14-27 days and 85 per cent at 1-2 months post-boost.
Sisonke 2 was conducted in approximately 350 vaccination centres across all nine provinces of South Africa.
Utilising data from a South African managed care organisation, trial investigators determined VE of the Johnson & Johnson Covid-19 booster shot (ni,092) as compared to other individuals enrolled in the same managed care organisation, during the period from November 15, 2021, through December 20, 2021.