According to a new South African study, a booster shot of Johnson & Johnson’s (J&J) single-dose COVID-19 vaccine showed 84 percent efficacy in preventing hospitalization in the country’s healthcare workers who became infected as the Omicron variant spread.
The results give great hope as the explosive rise of Omicron pushes the world to a record time of daily cases, and evidence emerges that the highly mutated strain can evade the protection that normally stems from vaccination.
The real-world study, which has not been peer-reviewed, was based on a second dose of the J&J vaccine administered to 69,092 workers between November 15 and December 20.
An initial course of inoculation has been found to give only greatly reduced protection against infection by Omicron, which is spreading quickly through many countries after first being identified in late November in southern Africa and Hong Kong. However, several studies have suggested that a booster dose provides significant protection against severe illness from the variant.
The new research found that the J&J vaccine’s effectiveness at preventing hospitalization rose from 63 percent shortly after a booster was administered to 84 percent 14 days later. Effectiveness reached 85 percent at one to two months post-boost.
“It reassures us that COVID-19 vaccines continue to be effective for the purpose they were designed, which is to protect people against severe disease and death. This is yet another piece of evidence that we have not lost that impact even in the face of a very mutated variant,” said Ms. Linda-Gail Bekker, the study’s co-lead investigator.
The researchers also noted that their analysis had several limitations, including short follow-up times, which averaged eight days for healthcare workers who had received their boost within the previous 13 days, or 32 days for those boosted for 1-2 months earlier, and which could skew overall vaccine effectiveness.