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Moderna says booster works against omicron; stocks fall after early spike

The company said its findings, which have not undergone scientific review, involve a booster that uses half the original dose.

Moderna Inc. announced Monday that a half-dose booster of its COVID-19 vaccine would increase antibody levels against the new omicron variant of COVID-19, the company reported, citing preliminary data.

The preliminary data signals that a booster could still give protection against the new concerning variant despite its mutations. That data hasn’t yet undergone scientific review. Testing by the U.S. National Institutes of Health, announced last week by Dr. Anthony Fauci, found a similar jump. 

As CNN Health reported, Moderna's current booster is given out as a 50-microgram dose. According to Moderna, its approved 50-microgram booster dose increased antibody levels by 37-fold, but the company said a 100-microgram booster dose could increase antibody levels by 83-fold. This is compared to levels which were studied before a booster was administered.

Moderna put the announcement on its investors section of its website posting a quote from Stéphane Bancel, Chief Executive Officer of Moderna who said, “The dramatic increase in COVID-19 cases from the Omicron variant is concerning to all. However, these data showing that the currently authorized Moderna COVID-19 booster can boost neutralizing antibody levels 37-fold higher than pre-boost levels are reassuring,” 

It's not certain if the data on increased antibody levels mean the booster will work clinically against the new omicron variant. But, as Bancel said, the preliminary data is "reassuring" to Moderna.

CNBC reported Moderna shares went up 6.8% in premarket trading on Monday after the announcement. But shares then fell 6.25% during the day to close at 276.38. It showed a modest rebound in the first half-hour of after hours trading.

Moderna said that a potential 100-microgram dose of its booster would be "generally safe and well tolerated."

A full does booster would come with an increase in the usual side effects, the company said. While half-dose shots are being used for most Moderna boosters, a full-dose third shot has been recommended for people with weakened immune systems.

Pfizer’s testing also found its COVID-19 vaccine triggered a similarly big jump in omicron-fighting antibodies. The vaccines made by Pfizer and by Moderna, both made with mRNA technology, are used by many countries around the world to fight the coronavirus.

Together, the available evidence backs health authorities’’ increasing pleas for people to get their boosters as soon as they’re eligible.

Antibody levels predict how well a vaccine may prevent infection with the coronavirus but they are just one layer of the immune system’s defenses. Other research suggests the vaccine still should induce good protection against severe disease if people do experience a breakthrough infection.

Both Moderna and Pfizer are developing shots to better match the omicron variant in case they’re needed.

The Associated Press contributed to this report. 


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