 Researchers say a booster dose of Johnson and Johnson single dose of COVID-19 vaccine was 84% effective at preventing hospitalization in South African healthcare workers who became infected as the Omicron variant spread. A South African study showed that a booster dose of Johnson and Johnson's COVID-19 vaccine was 84% effective at preventing hospitalization in healthcare workers who became infected as the Omicron variant spread. Researchers tracked data of over 69,000 workers between November 15 and December 20 after second doses of J&J vaccines were administered. The effectiveness at preventing hospitalization rose from 63% shortly after a booster to 84% 14 days later. Effectiveness reached 85% at one to two months post-boost. Linda Gail Becker, the co-lead investigator of the research, said this is another piece of evidence that vaccines have not lost that impact even in the face of a very mutated variant. She added that the jury was still out on the issue of further boosters for the J&J vaccine. The J&J vaccine has also proven to be easier to transport to remote African rural areas than the rival, two-dose VISA vaccine due to better heat tolerance. While an initial course of inoculation has been shown to offer reduced protection against Omicron infection, several studies have suggested that a booster dose still provides significant protection against severe illness.