A real-world study of health care workers in South Africa found that a booster dose of the Johnson & Johnson coronavirus vaccine was 85% effective at preventing COVID-19-related hospitalization, demonstrating strong protectiveness against the omicron variant.
The study looked at more than 69,000 health care workers between Nov. 15 and Dec. 20, when the omicron variant was prevalent in the country. The study showed that protection rose significantly after receiving a second dose of J&J, from 63% within 13 days of getting the second shot, to 84% at 14-27 days after and 85% 1-2 months post-boost.
Data from the study “confirm that the Johnson & Johnson COVID-19 booster shot provides 85 percent effectiveness against hospitalization in areas where Omicron is dominant,” Mathai Mammen, the Global Head of Janssen Research & Development, said in a statement. “This adds to our growing body of evidence which shows that the effectiveness of the Johnson & Johnson COVID-19 vaccine remains strong and stable over time, including against circulating variants such as Omicron and Delta.”
A separate study, a lab-based investigation in the United States, showed that a booster dose of the vaccine produced 41-fold increase in neutralizing antibodies and a 5-fold increase in T-cells against the omicron variant.
“We believe that the protection could be due to the robust T-cell responses induced by the Johnson & Johnson COVID-19 vaccine,” Dr. Mammen said. “Furthermore, these data suggest that Omicron is not affecting the T-cell responses generated by our vaccine.”
Results from the study have yet to be published in a peer-review journal, but have been submitted to the pre-print server medRxiv by the study’s authors, the company said.
While the J&J shot is authorized by the U.S. Food and Drug Administration, the Centers for Disease Control and Prevention recommend getting the Pfizer-BioNTech or Moderna shots over the J&J shot where available, citing the greater effectiveness of the other two shots in comparison.
The CDC has raised concerns about a link between the J&J shot and a risk of extremely rare blood clots, briefly pausing use of the shot in April, but later rescinded that pause after determining the benefits of the shot outweigh the risks.
The study should come as encouraging news to those who’ve received the J&J vaccine in the U.S. and worldwide.
Out of the 506 million COVID-19 vaccine doses administered in the U.S., just north of 17 million are Johnson & Johnson vaccines, according to data from the CDC. More than 16 million in the U.S. have been fully vaccinated with the J&J jab, with more than 1 million people receiving a booster dose of the shot.
