FDA backs changing Covid booster shots to target most recent omicron subvariants

There hasn’t been enough research on how much protection a fourth dose can offer, medical professionals told CNBC.

The Covid-19 booster shots should be updated to target the most recent omicron subvariants that are gaining ground in the U.S., according to the FDA.

Peter Marks, head of the FDA's vaccine division, said manufacturers should update their shots to target omicron BA.4 and BA.5 in addition to the original strain of the virus that first emerged in China.

The FDA's panel of independent experts voted overwhelmingly on Tuesday to recommend a vaccine switch after evaluating the benefits and drawbacks of updating the shots.

The vaccine makers can't keep up with the evolution of the virus. The original version of the variant, BA.1, caused a huge wave of infections in the winter.

BA.1 is no longer circulating in the US due to other omicron subvariants.

Marks said the two dose primary vaccine series will not be changed. When public health experts expect another wave of infections as immunity from the vaccines fades, the FDA wants to update the booster shots to make them more durable. It's easier to spread covid indoors.

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