Pfizer’s Covid vaccine for young children may not be renewed by the US Food and Drug Administration (FDA) this fall, prompting Moderna to fill possible gaps in supply, according to an email obtained by the Guardian.

The move would pull the only remaining Covid vaccine for all children under five from the market.

The Moderna vaccine is only approved for children with one or more health conditions, and the pediatric Covid vaccine from Novavax is only available for children aged 12 and up with health conditions.

“It certainly would create a hole in the availability of vaccines,” said Georges Benjamin, the executive director of the American Public Health Association.

“And to do it this late in the season – I think clearly it’s inappropriate.”

According to an email from the National Center for Immunization and Respiratory Diseases (NCIRD), Pfizer said the FDA recently informed the pharmaceutical company that it may not renew the emergency use authorization for its pediatric Covid vaccine for the 2025 respiratory season.

The email was sent on Friday to state and local vaccination grantees.

The Pfizer vaccine is given to children between the ages of six months and four years.

Pfizer expects its Covid vaccine for children aged five to 11 to be fully licensed this fall, the email said.

The Centers for Disease Control and Prevention (CDC) is “in discussions” with Moderna about rapidly increasing its Covid vaccine supply for young children, according to the email.

That includes internal planning about volume, timing, and potential supply gaps.

“We are working to ensure there will be sufficient supply,” said Chris Ridley, a Moderna spokesperson.

The CDC, the US Department for Health and Human Services (HHS), and Pfizer did not respond to media inquiries by publication time.

In July, Moderna received FDA approval of its Covid pediatric shot. But the vaccine was only approved for children with one or more health conditions that make them more vulnerable to Covid. This move could limit access to Covid vaccines.

“We already have a low number of people using the vaccines to start with,” Benjamin said.

“There hasn’t been enough promotion of vaccinations for kids, and then you have Mr [Robert F] Kennedy’s [Jr] unscientific statements about the safety and efficacy of vaccines, particularly Covid vaccines, for both pregnant women and kids. It has muddied the waters of what people know about the safety and efficacy of the vaccine.”

The vaccine is extremely effective, especially against hospitalization and death.

Yet only 5.6% of children aged six months to four years are vaccinated against Covid, and about 15% of children aged five to 17 are vaccinated, according to the CDC.

While older adults have the highest rates of hospitalization and death, children continue seeing hospitalization rates from Covid similar to rates in 2020 and 2021.

And there are other concerns with Covid infection.

“We don’t know the long-term impact for kids who have gotten Covid as a disease. We do know it does cause a multi-systemic inflammatory process in a number of kids, which is very severe, and we don’t know the long-term implications for long Covid in kids,” Benjamin said.

Covid cases are rising in many parts of the US amid other vaccine restrictions proposed and implemented by health officials.