The FDA today expanded the emergency use authorization (EUA) of the messenger RNA (mRNA)-based Pfizer/BioNTech COVID-19 vaccine by adding to its allowable uses in adolescents and some children.

The agency authorized a third “booster” dose of 0.3 mL for adolescents ages 12–15 in addition to the two-dose jab, and shortened from six to five months the time allowed between the completion of primary vaccination and the booster dose. Also authorized by the FDA was a third primary series dose for certain immunocompromised children five through 11 years of age.

The EUA expansion comes five months after the FDA granted its first formal approval to Pfizer and BioNTech for a COVID-19 vaccine, now marketed under the name COMIRNATY® (COVID-19 Vaccine, mRNA; also known as BNT162b2), and indicated for the prevention of COVID-19 disease in individuals 16 years of age and older.

In expanding the EUA, the FDA cited the surge of COVID-19 cases wrought by the Omicron variant (B1.1.529).

“With the current wave of the omicron variant, it’s critical that we continue to take effective, life-saving preventative measures such as primary vaccination and boosters, mask wearing and social distancing to in order to effectively fight COVID-19,” Acting FDA Commissioner Janet Woodcock, MD, said in a statement. “Throughout the pandemic, as the virus that causes COVID-19 has continuously evolved, the need for the FDA to quickly adapt has meant using the best available science to make informed decisions with the health and safety of the American public in mind.”

The FDA said it agreed to the expanded EUA after concluding that the protective health benefits of a single booster dose of the Pfizer-BioNTech COVID-19 Vaccine outweighed its potential risks in individuals ages 12–15 for providing continued protection against COVID-19 and associated consequences, including hospitalization and death.

The agency cited data from Israel, including safety data from more than 6,300 individuals ages 12–15 who received a booster dose of the vaccine at least five months following completion of the primary two-dose vaccination series. That data allowed the FDA to reassess the booster’s benefits and risks in younger adolescents during the current surge in COVID-19 cases.

No new safety concerns

According to the FDA, the data showed no new safety concerns emerging from a population of over 4.1 million individuals 16 years of age and older in Israel who received a booster dose at least five months following completion of the primary vaccination series. No new cases of myocarditis or pericarditis have been reported to date in these individuals.

In addition, the FDA cited peer-reviewed data from multiple laboratories indicating that a booster dose of the Pfizer-BioNTech COVID-19 Vaccine greatly improved an individual’s antibody response to the Omicron variant. That data led the agency to conclude that authorizing booster vaccination at five months rather than six months may provide better protection sooner for individuals against Omicron—and that the benefits of that five-month interval outweighed its risks.

The FDA also expanded the EUA to include a third primary series dose of 0.3 mL in children ages 5–11 who have undergone solid organ transplantation, or who have been diagnosed with conditions that are considered to have an equivalent level of immunocompromised. Such children may not respond adequately to the two-dose primary vaccination series, the agency found, hence the expanded authorization.

A two-dose primary series in children ages 5–11 was authorized via EUA in October 2021.

The FDA previously authorized a third primary series dose for use as part of the primary immunization series in individuals 12 years and older. Potential effectiveness of an additional dose in children 5 through 11 years of age was extrapolated from data collected in adults, the agency disclosed.

Pursuing expanded approval

On December 17, Pfizer and BioNTech said they submitted a supplemental Biologics License Application (sBLA) to the FDA seeking expanded full approval of COMIRNATY to include individuals ages 12-15. The sBLA included updated longer-term follow-up data from the companies’ pivotal Phase III clinical trial of 2,228 participants 12 through 15 years of age.

In that trial, a two-dose series of the Pfizer-BioNTech COVID-19 Vaccine (30-µg per dose) was 100% effective against COVID-19, measured seven days through over four months after the second dose, according to the companies. Among 30 confirmed symptomatic cases of COVID-19 in the trial with and without evidence of prior infection with SARS-CoV-2, all cases of COVID-19 were in the placebo group (N=1,129) and no cases were in the Pfizer-BioNTech vaccine group (N=1,131).

During an investor presentation following the sBLA announcement, Kathrin Jansen, PhD, Senior Vice President & Head of Vaccine R&D, presented Phase III data showing the effectiveness of the vaccine dipping from 96.2% at or after seven days to <2 months after the second primary dose, to 90.1% at or after two months to <4 months post dose 2, to 83.7% more than four months after dose 2—with the number of months ranging from 4 to 7.4 months.

Mikael Dolsten, MD, PhD, Pfizer’s Chief Scientific Officer and President, Worldwide Research Development and Medical, shared during the presentation that Pfizer and BioNTech plan to manufacture 4 billion doses of their COVID-19 vaccine this year, after producing 3 billion doses in 2021.

More than >75% of the total volume will be manufactured within Pfizer’s network of internal sites and CMOs, Dolsten said.

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