J&J Seeks FDA Clearance for Booster Vaccine 0:35
A new study from the National Institutes of Health (NIH) found that it is safe for people to receive a different Covid-19 booster vaccine than the vaccine they initially received and that they generate robust immune responses.
For people who initially received the Johnson & Johnson single-dose vaccine, a booster of the Pfizer or Moderna vaccine appeared to provide a stronger antibody response.
People who initially received the Pfizer or Moderna vaccine appeared to have a comparable response with either booster.
Among those evaluated at the beginning of the trial, protection against the delta and beta variants "increased substantially" after boosting.
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The study followed 458 people at clinical trial centers across the country.
The results have not yet been reviewed or published, but are expected to be discussed this Friday during a meeting of the vaccine advisers of the US Food and Drug Administration (FDA, for its acronym in English).
The boosters were tested in two age groups: people 18 to 55 years old and people 56 years and older.
The groups weren't large enough to compare their responses, according to the study.
All participants were observed for 30 minutes after receiving the injection.
The researchers also collected blood to determine the degree of immune response to the vaccine on days 1, 15, and 29. Participants were also asked to keep track of any side effects.
Side effects were similar to those experienced with the initial vaccine.
Half of the study participants experienced some side effect, such as injection site pain, tiredness, nausea, chills, headache, and muscle pain.
Most of the symptoms were felt between one and three days after the boost.
None of the side effects were serious.
Side effects of booster doses of the vaccine were similar to those of the second dose, brief and mild, according to a study
"Reactogenicity and adverse effects were similar in all booster groups," the study says.
"These data suggest that if a booster vaccine is approved or licensed, it will generate an immune response regardless of the initial covid-19 vaccination regimen."
Both Moderna and Pfizer use mRNA technology, a genetic material called messenger RNA that is delivered directly to cells to tell the body to produce small pieces of the virus to stimulate an immune response.
The Janssen vaccine is a viral vector vaccine, which uses an adenovirus modified so that it cannot replicate and which carries fragments of the coronavirus to stimulate the response.