The Centers for Disease Control and Prevention on Tuesday recommended that people who have received two shots of a Covid-19 vaccine produced by Johnson & Johnson and Janssen follow up with a booster of one of the FDA-approved mRNA vaccines from Pfizer-BioNTech and Moderna, which could produce a stronger immune response and lessen the risk of rare but severe side effects.
Analyzing 80,287 emergency department and urgent care visits across 10 states from December to March, the researchers found that two Johnson & Johnson doses was 54% effective at preventing Covid-associated emergency department or urgent care visits, compared to 79% after one Johnson & Johnson dose and one dose of either of the mRNA vaccines–comparable to the effectiveness offered by three shots of an mRNA vaccine, the CDC said.
The researchers also found that two Johnson & Johnson doses was 67% effective at preventing hospitalization, compared to 78% after one Johnson & Johnson dose and one dose of either of the mRNA vaccines, based on data from 25,244 hospitalizations among patients with Covid-like illness.
The CDC’s recommendation that patients mix and match vaccine types was also informed by data associating Johnson & Johnson’s vaccine with rare but severe side effects like thrombosis—when clots block blood vessels—and Guillain-Barré syndrome—an immune disorder that can cause paralysis.
Though little data has been gathered about the effects of mixing Johnson & Johnson shots with Pfizer or Moderna’s, the new study reinforces findings from a previous cohort study of U.S. veterans that provisionally indicated that one Johnson & Johnson shot and one shot from Pfizer or Moderna gave better protection against the omicron variant of the coronavirus than two Johnson & Johnson shots, the CDC said.
Though the CDC recommends that everyone age 18 and over get a booster shot, only 48.2% of Americans in that age group have been boosted so far, including 67.2% of people 65 and older.
Pfizer-BioNTech and Moderna’s vaccines are based on messenger RNA, which provides instructions to a body’s cell to produce an antigen against coronavirus, while Johnson & Johnson’s vaccine uses an older method of introducing a piece of the virus into the body to provoke an immune system response. Though initial trials indicated Johnson & Johnson’s shot was highly effective, later research estimated its effectiveness at preventing hospitalization at around 68%, below competing vaccines. Use ofJohnson & Johnson’s vaccine has also been limited due to its risk of serious side effects, which, while rare, are still greater than the risks for Pfizer and Moderna’s vaccines. A study published March 2 by JAMA Network Open found that Johnson & Johnson’s vaccine was five times less effective than Pfizer’s vaccine at keeping patients out of the hospital with severe Covid. However, the CDC still recommends Johnson & Johnson’s vaccine for anyone who has had a severe reaction to Pfizer or Moderna’s vaccines or who would otherwise go unvaccinated due to lack of access to Pfizer or Moderna’s vaccines.
The study published Tuesday took place over a limited timeframe, monitoring patients for no more than 120 days after vaccination, researchers said. Additionally, the low number of study participants who had received Johnson & Johnson’s vaccine made it impossible to break down vaccine effectiveness according to demographic categories like age and race.
“Risk Of Covid Hospitalization 5 Times Higher With Johnson & Johnson Shot Than Pfizer” (Forbes)