Three Doses of Pfizer’s Covid-19 Vaccine 80% Effective in Young Children, Company Says

Many of the children had received at least some of their shots during the Omicron wave, suggesting that the three-dose series worked well against the highly contagious variant after the two doses produced mixed results.

“We have a big problem called Omicron, and I think we have a good solution,” Pfizer Chief Executive

Albert Bourla

said in an interview.

The companies reported the findings without much detail via press release based on an early analysis of study results.

Though preliminary, the results could set the stage for the last remaining group of people to get access to shots. Pfizer and BioNTech said they plan to complete submissions this week with U.S. health regulators.

The companies issued their findings while the Food and Drug Administration weighs an application from

Moderna Inc.

to permit its two-dose vaccine for children between ages 6 months and 5 years old.

The FDA has scheduled meetings of outside medical advisers on June 14 and 15 to discuss data from Pfizer-BioNTech’s and Moderna’s vaccine trials in young children.

People 5 years and older are eligible to get a Covid-19 vaccine and booster from Pfizer-BioNTech. Moderna’s and

Johnson & Johnson’s

shots are cleared for older people.

Approximately 19 million children in the U.S. are under 5 years of age. Children tend to experience mild symptoms if infected with Covid-19. Yet some have become seriously ill, especially during the recent Omicron surge.

Health authorities and vaccine experts say inoculating the youngsters will protect them and older adults against Covid-19, including parents, grandparents and teachers who are at higher risk of severe disease.

Some parents have expressed eagerness to vaccinate their children. Yet polls show that large numbers of parents either don’t plan to get their child vaccinated at all, or only if required to do so.

A series of events has delayed availability of shots for young children.

In December, Pfizer and BioNTech said they were holding off on seeking FDA authorization after testing found two doses generated a weaker-than-expected immune response in children ages 2 to 4.

The companies said they wanted to see if three doses of the vaccine produced a stronger immune response.

Yet three months later, in February, the companies went ahead and sought authorization of the two doses in young children. The FDA had encouraged the companies to file the application, The Wall Street Journal reported.

Shortly before the FDA was expected to release its staff’s assessment of the application, however, the agency postponed its review to wait for more testing of two- and three-dose regimens, the Journal reported.

The latest Pfizer-BioNTech study results haven’t been peer-reviewed by independent experts or published in a medical journal.

In the study, children 6 months to 5 years old received three doses of 3 micrograms of the vaccine.

By comparison, people 12 years and older receive a primary series of two 30-microgram doses. Children ages 5 to 11 receive two 10-microgram doses, and are eligible for a booster of the same dose.

Some 1,678 of the young children in the study received a third dose at least two months after getting a second dose, at a time when Omicron was the predominant form of the virus, according to the companies.

The immune responses of a subset of subjects studied one month after getting a third dose were comparable to the strong responses of people ages 16 to 25 who had gotten two doses in another trial, Pfizer and BioNTech said.

The companies didn’t specify the immune response the third dose generated, such as providing the level of antibodies.

As of April 29, 10 young subjects had developed symptomatic Covid-19 within seven days after their third dose, the companies said.

The cases resulted in an efficacy rate of 80.3% in preventing symptomatic disease, according to the companies. They didn’t break down how many of the infected subjects got three doses of the vaccine and how many were on placebo.

The analysis is preliminary, because the companies designed the trial to do a final review after at least 21 cases of Covid-19 develop.

Write to Jared S. Hopkins at [email protected]

Many of the children had received at least some of their shots during the Omicron wave, suggesting that the three-dose series worked well against the highly contagious variant after the two doses produced mixed results.

“We have a big problem called Omicron, and I think we have a good solution,” Pfizer Chief Executive

Albert Bourla

said in an interview.

The companies reported the findings without much detail via press release based on an early analysis of study results.

Though preliminary, the results could set the stage for the last remaining group of people to get access to shots. Pfizer and BioNTech said they plan to complete submissions this week with U.S. health regulators.

The companies issued their findings while the Food and Drug Administration weighs an application from

Moderna Inc.

to permit its two-dose vaccine for children between ages 6 months and 5 years old.

The FDA has scheduled meetings of outside medical advisers on June 14 and 15 to discuss data from Pfizer-BioNTech’s and Moderna’s vaccine trials in young children.

People 5 years and older are eligible to get a Covid-19 vaccine and booster from Pfizer-BioNTech. Moderna’s and

Johnson & Johnson’s

shots are cleared for older people.

Approximately 19 million children in the U.S. are under 5 years of age. Children tend to experience mild symptoms if infected with Covid-19. Yet some have become seriously ill, especially during the recent Omicron surge.

Health authorities and vaccine experts say inoculating the youngsters will protect them and older adults against Covid-19, including parents, grandparents and teachers who are at higher risk of severe disease.

Some parents have expressed eagerness to vaccinate their children. Yet polls show that large numbers of parents either don’t plan to get their child vaccinated at all, or only if required to do so.

A series of events has delayed availability of shots for young children.

In December, Pfizer and BioNTech said they were holding off on seeking FDA authorization after testing found two doses generated a weaker-than-expected immune response in children ages 2 to 4.

The companies said they wanted to see if three doses of the vaccine produced a stronger immune response.

Yet three months later, in February, the companies went ahead and sought authorization of the two doses in young children. The FDA had encouraged the companies to file the application, The Wall Street Journal reported.

Shortly before the FDA was expected to release its staff’s assessment of the application, however, the agency postponed its review to wait for more testing of two- and three-dose regimens, the Journal reported.

The latest Pfizer-BioNTech study results haven’t been peer-reviewed by independent experts or published in a medical journal.

In the study, children 6 months to 5 years old received three doses of 3 micrograms of the vaccine.

By comparison, people 12 years and older receive a primary series of two 30-microgram doses. Children ages 5 to 11 receive two 10-microgram doses, and are eligible for a booster of the same dose.

Some 1,678 of the young children in the study received a third dose at least two months after getting a second dose, at a time when Omicron was the predominant form of the virus, according to the companies.

The immune responses of a subset of subjects studied one month after getting a third dose were comparable to the strong responses of people ages 16 to 25 who had gotten two doses in another trial, Pfizer and BioNTech said.

The companies didn’t specify the immune response the third dose generated, such as providing the level of antibodies.

As of April 29, 10 young subjects had developed symptomatic Covid-19 within seven days after their third dose, the companies said.

The cases resulted in an efficacy rate of 80.3% in preventing symptomatic disease, according to the companies. They didn’t break down how many of the infected subjects got three doses of the vaccine and how many were on placebo.

The analysis is preliminary, because the companies designed the trial to do a final review after at least 21 cases of Covid-19 develop.

Write to Jared S. Hopkins at [email protected]