An additional booster dose of any of the three FDA-cleared emergency use-approved anti-coronavirus drugs is safe and induces the desired immune response. This was confirmed by scientists at the US National Institutes of Health, who published preliminary results of their research in The New England Journal of Medicine.
The study involved 458 people who were vaccinated at least 12 weeks before the start of the study and who were not diagnosed with coronavirus infection. Each volunteer was given one booster dose of one of three vaccines - Janssen/Johnson & Johnson (150 people), Moderna (154 people), or Pfizer-BioNTech (154 people).
All participants kept diaries of any side effects. More than half of the subjects reported headache, pain at the injection site, muscle pain and malaise after the administration of the booster dise. No more serious adverse events associated with vaccination have been reported.
The study showed that all combinations of primary and booster vaccination increased levels of neutralizing antibodies (ranging from 4.2 to 76 times the pre-booster level). The level of binding antibodies increased by 4.6-56 times. The administration of a different booster vaccine from the primary vaccine also elicited a similar or even higher immune response compared to boosters of the same vaccine with which the first two vaccinations were given.
The results cover immunogenicity data during the first 29 days after revaccination. The researchers plan to continue to follow the subjects for one year to evaluate the effect of the boosters on long-term immune responses.