Johnson & Johnson announced new preliminary results from the South African Phase 3b Sisonke 2 study, which showed that “a homologous booster (with the same vaccine) of Johnson & Johnson’s Covid-19 vaccine (Ad26.COV2.S) has been shown to be up to 85% effective against disease-related hospitalization. ” This was announced by the company in a statement.
“Data from the Sisonke 2 study confirm that Johnson & Johnson’s Covid-19 vaccine booster guarantees 85% efficacy against hospitalization in regions where Omicron is dominant. This adds to our growing body of evidence. which shows that the efficacy of Johnson & Johnson’s vaccine against Covid-19 remains strong and stable over time, even against variants in circulation such as Omicron and Delta “, said Mathai Mammen, M.D., Ph.D., Global Head, Janssen Research & Development, LLC, Johnson & Johnson.
“We believe – he continues – that the protection may be due to the robust T cell responses induced by the Johnson & Johnson Covid-19 vaccine. Furthermore, these data suggest that Omicron is not affecting the T cell responses generated by our vaccine” .
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The data on the efficacy “of the booster of the Ad26.COV2 vaccine against Omicron are important – he adds Nicholas Crisp, Deputy Director General of the South African National Department of Health – as this vaccine is part of our arsenal to fight Covid. These data should reassure health workers who have not yet made the booster and convince them to get vaccinated as soon as possible “.
The analysis of humoral and cellular responses against Omicron involved 65 people who received primary vaccination with two doses of Pfizer / BioNTech and then a homologous booster (24 of them) or heterologous with J&J (41) after at least six months, revealed that both regimens increased humoral and cellular responses against Omicron.
The South African study on homologous recall
The Sisonke 2 study, conducted by the South African Medical Research Council (Samrc), “showed that the Johnson & Johnson recall reduced the risk of hospitalization from Covid-19 among healthcare workers in South Africa after Omicron became the dominant variant. “. During the months the study was ongoing (mid-November to mid-December) the frequency of Omicron increased from 82 to 98% of Covid-19 cases in South Africa as reported by Gisaid, an initiative that provides data on the COVID-19.
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The analysis on the efficacy of the heterologous recall
A second separate analysis of the immune response to different vaccine regimens, conducted by Beth Israel Deaconess Medical Center (Bidmc), showed that “a heterologous booster (with a different vaccine) of Johnson & Johnson’s Covid-19 vaccine in people who initially received the BNT162b2 mRNA vaccine – the note released by J&J reads – generated a 41-fold increase in neutralizing antibody responses within four weeks after booster and a 5.5-fold increase in CD8 + T cells towards Omicron within two weeks. A homologous booster with BNT162b2 generated a 17-fold increase in neutralizing antibodies within four weeks after the booster and a 1.4-fold increase in CD8 + T cells within two weeks. “
“Since the Omicron variant has mutated from the original sars-cov-2 strain, there is a need to understand how effective the currently licensed covid-19 vaccines are in protecting against severe forms of the disease. Our analysis shows that a recall of the johnson & johnson vaccine against covid-19 generated a robust increase in both neutralizing antibodies and T-cells against omicron, “he concluded. Dan Barouch, mD, Ph.D., Director of the Center for Virology and Vaccine Research at Bidmc.
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