US regulators assess if COVID-19 vaccine recipients can mix booster shots

US health regulators are now considering revising the rules for COVID-19 vaccines in a bid to allow people to opt for a different type of shot for their booster than what they originally received. If approved, the move means that it would enable people who got the Johnson & Johnson vaccine to receive the Moderna or Pfizer dose as their next shot. Similarly, people who received the Moderna or Pfizer vaccine might be able to boost with the J&J shot. 

According to ABC News, a decision regarding mixed COVID booster shots, however, has not been made yet. It is also still not clear how soon mixed doses could happen. The US Food and Drug Administration would need to amend its authorisation of the three vaccines available to Americans, and the CDC, on the other hand, would have to endorse the idea. But it is to mention that in a meeting Friday with independent advisers, senior government officials reportedly suggested that they were open to the idea. 

Dr Peter Marks, a senior FDA official who oversees vaccine regulation, said that it does seem like there is some consensus that this is an “important option” for people to have. He said that providing regulator flexibility was possible, and further asked the advisory panel to weigh in on what data might be needed to make such a decision. However, Mark did not offer a timetable and suggested that he would be interested in collecting more real-world data first. 

Mixing booster shots ‘safe and effective’ 

Separately, Amanda Cohn, a senior adviser for vaccines at CDC’s National Center for Immunization and Respiratory Diseases, said that having “allowable language” from the FDA would be helpful from a public health perspective. She expressed concern over the fact that 15 million people who received the first shot of J&J may not have access to a second dose or they might be concerned about the risk of rare but serious side effects. Therefore, if there is not any allowable language in the FDA factsheets or EUA authorisation, then those individuals are left behind, Cohn said. 

Meanwhile, results from a previous study by the NIH found that boosting with a different shot than what was received the first time around appears to be safe and effective. In fact, the study had revealed that J&J recipients would end up with higher antibody levels if they were boosted with Moderna or Pfizer vaccines. Cohn also said that there do not appear to be any safety concerns with mixing booster doses of any type. 

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