A booster dose of Johnson & Johnson Inc’s single-dose COVID-19 vaccine was 84% effective at preventing hospitalizations in South African healthcare workers who became infected as the Omicron variant spread, researchers there said on Thursday.
The real-world study, which has not been peer-reviewed, was based on a booster dose of the J&J vaccine administered to 69,092 workers between November 15th and December 20th. The South African study showed the J&J vaccine’s effectiveness at preventing hospitalization rose from 63% shortly after a booster was administered to 84% 14 days later. Effectiveness reached 85% at one to two months post-boost.
Researchers said their analysis had several limitations, including short follow-up times. Those averaged eight days for healthcare workers who had received their boost within the previous 13 days, or 32 days for those boosted 1-2 months earlier.
• Johnson & Johnson booster effective against hospitalisation in South Africa, early results suggest
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An initial course of the singular Johnson & Johnson vaccine had been shown to offer only greatly reduced protection against infection by Omicron, which is spreading quickly through many countries after first being identified in southern Africa and Hong Kong in late November. However, several studies have suggested that a booster dose provides significant protection against severe illness from the variant.
2 doses of Johnson & Johnson’s Covid-19 vaccine slashed hospitalizations caused by the omicron variant in South Africa by up to 85%, a critical finding since the shot is being increasingly relied upon across the continent, researchers said https://t.co/I34f6GLAwp pic.twitter.com/zyCi1NnuHW
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The Omicron variant increased from 82% to 98% at the time of the study, researchers said. No decisions have been made on the issue of further boosters for the J&J vaccine, which is administered as a single shot for the first full dose, and which is easier to transport to remote African rural areas than the rival, two-dose Pfizer mRNA vaccine due to better heat tolerance.
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