Two reports released Thursday show that people who get booster doses of Johnson & Johnson’s Janssen vaccine are well protected against severe disease and hospitalization from the Omicron variant of coronavirus, the company said.
Data from one real-life study from South Africa showed vaccine effectiveness against hospitalization from Covid-19 rose to 85% after a booster dose of the J&J vaccine, even after the Omicron variant was circulating. And data from a lab-based study in the US indicated the vaccine stimulates a strong immune response from cells known as T-cells, which protect people against severe disease even if they don’t block the virus entirely from infecting the body.
Results from both studies were released by the company in a statement but are being submitted to a pre-print server and a peer-reviewed journal, the company said.
A team at the South African Medical Research Council helped examine the results of an ongoing study of the J&J vaccine there. They looked at results from 69,000 health care workers. “When a booster shot was administered six to nine months after a primary single dose, vaccine effectiveness increased over time from 63 percent at 0-13 days, to 84 percent at 14-27 days and 85 percent at 1-2 months post-boost,” J&J said in a statement.
“Even before you factor in the increased infectiousness of Omicron, we have to remember that healthcare workers on the frontlines are at a greatly increased risk of being affected by COVID-19 in the first place,” Dr. Glenda Gray, president and CEO of the SAMRC, said in a statement. “We are therefore encouraged to see that boosting with the Johnson & Johnson COVID-19 vaccine regimen provides strong protection in a challenging real-world setting where there is an elevated risk of exposure – not just to COVID-19, but to the highly transmissible Omicron variant.”
Separately, Dr. Dan Barouch and colleagues at the Beth Israel Deaconess Medical Center in Boston looked at blood taken from 65 vaccinated volunteers and tested it against the Omicron variant. They looked at both antibodies – the first line of defense against infection – and T-cells.
Using the J&J vaccine as a booster for people who originally got two doses of Pfizer/BioNTech’s vaccine generated a 41-fold increase in neutralizing antibodies and a five-fold increase in the CD8 killer T cells that destroy cells infected by the virus. That stops the virus from replicating and spreading. Boosting with the Pfizer vaccine generated a 17-fold increase in neutralizing antibodies and a 1.4-fold increase in CD8 T cells four weeks later, they found.
“These data are important and these data are hopeful,” Barouch told CNN. They indicate that all Covid-19 vaccines can protect people from severe disease and death, even from the Omicron variant with all its mutations, he said.