Johnson & Johnson COVID booster offers serious protection against hospitalization from omicron variant

An additional dose of the one-shot J&J vaccine boosted the odds of avoiding hospitalization to 85%, according to a new study from South Africa.

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Though the CDC has raised concerns about blood clots associated with Johnson & Johnson's vaccine, a new report shows its use as a booster is more effective in preventing serious disease from COVID than a Pfizer booster.

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A booster of Johnson & Johnson's one-shot vaccine provides strong protection against the omicron variant of COVID-19, according to a study published Thursday.

The study, by the South African Medical Research Council and others, has not yet been peer-reviewed, but it looked at data from 69,000 South African health care workers this fall. It found that, for individuals who already received one dose of the J&J vaccine, known as Ad26.COV.2, a booster given six to nine months later improved their odds against hospitalization from 63% to 85%.

The results represent the earliest proof of the Johnson & Johnson booster's effectiveness, the study's authors wrote, in a time and place when the more contagious omicron variant is running rampant. In the period examined -- mid-November to mid-December 2021 -- omicron infections in South Africa shot up to represent 98% of all confirmed COVID cases, according to GISAID.

In the US, omicron is responsible for more than 58% of all new infections, the US Centers for Disease Control and Prevention reports

"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," Dr. Mathai Mammen, global head of Janssen Research & Development, a pharmaceutical subsidiary of Johnson & Johnson, said in a statement.


Only 54 cases of a rare blood-clotting condition have been reported among the more than 17 million people who have received a J&J jab.

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A separate analysis of "mixing-and-matching" vaccines conducted by Boston's Beth Israel Deaconess Medical Center found a J&J booster given to individuals who were initially given two doses of Pfizer's mRNA vaccine generated a 41-fold increase in antibody response within a month, compared to only a 17-fold increase when given a booster of the Pfizer vaccine.

The J&J booster also generated a five-fold increase in T-cells that fight omicron within two weeks, the company said, compared to a 1.4-fold increase with a second dose of Pfizer's formula.  

"As the omicron variant has mutated from the original SARS-CoV-2 strain, there is a need to understand how effective currently authorized COVID-19 vaccines remain at protecting against severe disease," said Dr. Dan Barouch, director of BIDMC's Center for Virology and Vaccine Research. "Our analysis shows that a booster shot of the Johnson & Johnson COVID-19 vaccine generated a robust increase in both neutralizing antibodies and T-cells to [combat] omicron."

Unlike Moderna and Pfizer's vaccine, the J&J shot is a viral-vector vaccine that uses an inactive cold virus modified to contain COVID protein-making genes that the body's immune system can respond to. 

The US Food and Drug Administration gave emergency use authorization to J&J's vaccine in February and approved a booster shot in October. But earlier this month, the CDC recommended Americans try to receive Pfizer or Moderna's mRNA vaccines, because of a rare but potentially fatal blood-clotting disorder that can occur within three weeks of receiving the Johnson & Johnson shot.  

Only 54 cases of the condition, called thrombosis with thrombocytopenia syndrome, have been reported among the more than 17 million people who have received a J&J jab, though at least nine deaths have been associated with it. Given their wide availability and the severity of the side effects, a committee of scientists and doctors found the CDC should "prefer" the other two vaccines.

The FDA has updated its fact sheet on Johnson & Johnson's vaccine but says the risks from COVID far outstrip those of getting blood clots from the J&J vaccine, which even in the highest-risk group, women ages 30-49, have only affected one in 100,000 people.

In a Dec. 16 statement, Johnson & Johnson said it "remains confident in the overall positive benefit-risk profile of its COVID-19 vaccine."
"The safety and well-being of those who use the Johnson & Johnson vaccine continue to be our number one priority," Mammen said. "We appreciate today's discussion and look forward to working with the CDC on next steps."

Because Johnson & Johnson's vaccine is a one-time shot and doesn't require refrigeration, it makes it easier and faster for people to become fully vaccinated. It's been more widely used in developing countries, where as little as 8.4% of the population has received a dose of a COVID-19 vaccine, according to Our World in Data

"This data is important given the increased reliance on the Ad26.COV.2 vaccine in Africa," the authors of the study said.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.