Pfizer and BioNTech logosCOVID-19 vaccine developers Pfizer (NYSE:PFE) and its partner BioNTech (Nasdaq:BNTX) have won emergency use authorization (EUA) for a single booster dose of their omicron BA.4/BA.5-adapted bivalent COVID-19 booster for kids between 6 months and 4 years of age.

The booster can be administered at least two months after completing the primary vaccination series with three doses of the original Pfizer-BioNTech COVID-19 vaccine. Additionally, FDA has authorized the bivalent vaccine for use as the third dose in a primary series for the same age group. The agency, however, has not yet authorized a fourth booster dose.

Trial data Supports bivalent vaccine safety and efficacy

The EUA is based on data from substudies within the companies’ Phase 1/2/3 trial (NCT05543616) evaluating the safety, tolerability and immunogenicity of a fourth bivalent vaccine dose in 300 children aged 6 months to 4 years. A subset of 60 study participants within the same age group demonstrated improved omicron BA.4/BA.5-neutralizing antibody responses after receiving the bivalent vaccine booster compared to those who received three doses of the original vaccine. The safety and tolerability profile of the bivalent vaccine was similar to that of the original vaccine.

Although PFE shares experienced a 1% increase to $40.28 today, Pfizer’s stock has declined by more than 21% since the start of the year.

The company has projected that its revenue could fall by one-third in 2023 as a result of lowered demand for COVID treatments. UBS analysts have downgraded Pfizer stock to neutral and slashed COVID revenue estimates by almost 50%.

The company recently entered into a partnership with Emory to develop next-gen COVID-19 therapies.

Pfizer is also looking beyond COVID for revenue opportunities. The company recently struck a deal with cancer drugmaker Seagen (Nasdaq:SGEN) to bolster its cancer portfolio. Pfizer leaders have also vowed to secure several key new approvals in the near future.

Bivalent boosters effective despite low demand

To date, demand for bivalent COVID-19 boosters has been weak owing partly to booster fatigue, as the American Medical Association noted in an editorial.

Bivalent boosters, however, are effective. Pfizer noted that recent real-world evidence indicates that the omicron BA.4/BA.5-adapted bivalent vaccines provide protection against symptomatic COVID-19 disease in adults caused by both BA.4/BA.5 and XBB omicron sublineages. The latter currently accounts for more than 85% of COVID-19 cases in the U.S.

Real-world evidence collected between September and December 2022 shows that among older adults, mRNA-based bivalent boosters offered greater vaccine effectiveness against COVID-19 hospitalization than two or more doses of the original vaccine administered two months earlier.

Pfizer and BioNTech have also submitted an application to the European Medicines Agency (EMA) to extend the marketing authorization for the omicron BA.4/BA.5-adapted bivalent vaccine to include its use in children aged 6 months to 4 years for both primary series (all three doses) and booster vaccination (fourth dose).

At present, the bivalent vaccine is authorized in the European Union as a booster dose for individuals aged 5 years and older. The companies plan to submit applications to other regulatory authorities worldwide for the use of their Omicron BA.4/BA.5-adapted COVID-19 booster for kids under 5 years of age.