- People who have received the J&J vaccine may get a better immune response from a Moderna or Pfizer booster, a major new study suggests.
- J&J recipients generated significantly more antibodies after a Moderna or Pfizer shot, instead of a second J&J jab.
- However, higher levels of antibodies do not necessarily mean that a person is more protected against the coronavirus.
The first US study to mix and match COVID-19 vaccine boosters from Moderna, Pfizer, and Johnson & Johnson has been released, and it looks like you can boost any vaccination licensed in the US with any other vaccine. safely – while stimulating J&J with Moderna or Pfizer may elicit a stronger immune response, at least initially.
The new study, funded by the U.S. National Institutes of Health, has shown above all that mixing and matching COVID-19 vaccines is a perfectly safe thing to do.
“What the study shows is that regardless of what an individual originally received, being boosted with one of the three vaccines we evaluated, that of Moderna, that of Janssen, that of Pfizer, led to good antibody responses in each of the groups, ”lead study author Dr. Robert Atmar of Baylor College of Medicine told Insider shortly after the study. publication of its new data on Wednesday.
The mix-and-match study recruited 458 people from 10 different medical centers across the United States who were each fully vaccinated with Moderna’s, Pfizer’s or J & J’s [Janssen] vaccine. Volunteers were then boosted with one of these three shots, resulting in nine different mix and match combinations. The researchers tested the blood of these volunteers periodically throughout the following month, comparing their levels of anti-virus proteins called neutralizing antibodies.
The study provides some of the clearest evidence to date that all booster injections – Pfizer, Moderna and J&J – increase antibody levels, but a booster vaccine from Moderna or Pfizer gives a stronger response. than another J&J vaccine. (This is similar to what researchers in Europe found by stimulating AstraZeneca’s vaccine with Pfizer.)
People who received their first shots from J&J saw the strongest responses from Pfizer or Moderna boosts
The most marked improvement in neutralizing antibody responses – which is an imperfect but easy-to-test indicator for measuring initial vaccine-induced immunity – came from people who initially received J&J’s vaccine.
In this group, a booster injection of J&J increased the levels of neutralizing antibodies by 4.2-fold on average. But J&J recipients who received an injection of Moderna saw their antibodies increase 76-fold, and a Pfizer booster was increased 35-fold. The differences between these groups were statistically significant, meaning that it is highly unlikely that ‘they are the result of chance.
The researchers warn that with only about 50 people in each group, this study is too small to fairly compare different vaccine booster combinations side-by-side, and the trial’s limited follow-up time (of just one month) does not. not tell us how long-term protection each booster can be.
Atmar warned that this study was “not designed to really make comparisons between different groups”, but rather “to quickly provide data for public health decisions.”
Yet, he acknowledged, “the natural thing” people do “is want to compare.” And the tables show some glaring differences:
The same trends above were true for neutralizing antibody titers, a more enduring (though still not perfect) picture of vaccine-induced immunity.
Antibodies aren’t everything when it comes to immunity
Atmar warned that doesn’t mean we all need mRNA boosters.
“I don’t think we’re going to want to end up boosting people every six months,” he said.
While antibodies are a key part of the body’s initial immune response, there are other long-term components of immune memory, such as the cellular immune response, that were not measured in this study.
Regarding side effects, by far the most common complaint after the booster was mild arm pain, experienced by over 70% of patients in all mixed groups.
Health regulators to vote on boosters this week and next
The eagerly awaited study is one of the most convincing pieces of research on the safety and immunogenicity of boosters. And it comes at a critical time, too: An FDA panel of experts will meet on Thursday and Friday to discuss Moderna and J&J boosters, while a CDC panel will meet on the same issue next week. (The third dose of Pfizer was accepted by both last month.)
J & J’s recall request has already come under scrutiny by the FDA, with agency scientists pointing to a lack of strong clinical trial results supporting a six-month recall.