Phase IIIb Sisonke study of Ad26.COV2.S shows 85% effectiveness against COVID-19.- Johnson & Johnson

The study, conducted by the South African Medical Research Council (SAMRC), showed that the Johnson & Johnson booster reduced the risk of hospitalization from COVID-19 among healthcare workers in South Africa after Omicron became the dominant variant. During the months studied (mid-November to mid-December) the frequency of Omicron increased from 82 to 98 percent of COVID-19 cases in South Africa as reported by GISAID, an initiative that provides COVID-19 data.

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 neutralizing antibody responses and a 5-fold increase in CD8+ T-cells to Omicron by four weeks following the boost. A homologous boost with BNT162b2 generated a 17-fold increase in neutralizing antibodies and a 1.4-fold increase in CD8+ T-cells by four weeks following the boost. Both neutralizing antibodies and CD8+ T-cells were higher four weeks after the boost with the Johnson & Johnson vaccine than with the BNT162b2 vaccine.