The U.S. Food and Drug Administration told vaccine makers Thursday that Covid boosters for this fall and winter should contain components targeting Omicron’s BA.4 and BA.5 sublines.
Earlier this week, an agency-convened panel of medical experts voted to update Omicron Covid vaccines, with most saying they would prefer shots targeting the latest iterations rather than the original BA.1 form, as the latter feared would become too outdated.
BA.4 and BA.5, which are more transmissible and immune-preventable, now account for more than 52 percent of US Covid cases, according to an official tracker.
“We have advised manufacturers wishing to update their Covid-19 vaccines to develop modified vaccines that add an omicron BA.4/5 spike protein component to the current vaccine composition to create a two-component (bivalent) booster vaccine ‘ the FDA said in a statement.
These vaccines would also need to target the original Wuhan strain to increase the breadth of the immune response.
Pfizer and Moderna, which make messenger RNA Covid vaccines, have developed and tested vaccines against BA.1, and representatives from both companies said during the expert meeting that it would take them about three months to produce BA.4 and BA. 5 vaccines to be manufactured on a large scale.
Pfizer shared initial results showing its BA.4/5 vaccine elicited a strong antibody response in mice, but it has not yet been tested in humans.
Novavax, which makes a protein subunit vaccine, said it could offer BA.4/5 vaccines by the end of the year.
The FDA said in its new statement that companies would need to submit human data before approval.
The “primary series,” or the first shots a person receives, would remain against the original strain, the FDA added.
While previous “variants of concern” like Alpha and Delta eventually dried up, Omicron and its sublines have dominated throughout 2022 to the point where it encompasses the vast majority of all Covid in the world, FDA official Jerry Weir said at the expert meeting this week.
This makes it more likely that future evolution of the virus will also occur along the Omicron branch of the Covid family tree, he added.
Earlier this month, the World Health Organization also recommended the use of Omicron boosters after a first series against the original strain.
#directs #pharmaceutical #companies #manufacture #Covid #boosters #targeting #BA.4 #BA.5