Outside advisers to the US Food and Drug Administration are meeting on Tuesday to discuss whether to change the design of COVID-19 vaccines in order to combat future variants of the coronavirus.
The updated shots are likely to be redesigned to fight the Omicron variant of the coronavirus, experts say. The exact composition of the retooled shots and whether they also will include some of the original vaccine alongside new components will be considered at the meeting.
Pfizer Inc, Moderna Inc and Novavax Inc are scheduled to present data at the meeting. All three companies have been testing versions of their vaccines updated to combat the BA.1 Omicron variant that was circulating and led to a massive surge in infections last winter.
Both Moderna and Pfizer with partner BioNTech have said that their respective redesigned vaccines generate a better immune response against BA.1 than their current shots that were designed for the original virus that emerged from China.
They have said that their new vaccines also appear to work against the more recently circulating BA.4 and BA.5 Omicron subvariants, even though that protection is not as strong as against BA.1.
Experts also want to know if the new shots will increase protection against severe disease and death for younger, healthier people or merely offer a few months additional safeguard against mild infection.
Scientists who have questioned the value of booster shots for young and healthy people have said a broad campaign is not needed with an updated shot either.
Others experts have championed any additional protection new vaccines may offer.