The Food and Drug Administration (FDA) on Friday cleared Novavax’s COVID-19 vaccine for emergency use in adolescents, paving the way to expand eligibility for the fourth shot available in the United States.

The two-dose regimen utilizes protein-based technology previously leveraged in vaccines to combat other viruses, offering an alternative for Americans skeptical of Pfizer and Moderna’s mRNA technology.

Providers can begin administering the vaccine to people aged 12 through 17 after a sign off from the Centers for Disease Control and Prevention (CDC), which has already authorized the vaccine’s use for adults. The two doses are given three weeks apart.

“Having more vaccine options for use in both adults and adolescents, like the Novavax COVID-19 Vaccine, Adjuvanted will hopefully help increase vaccination rates, particularly as we prepare for ongoing surges of COVID-19 with the start of fall and the back-to-school season,” Novavax President Stanley Erck said in a statement. 

“We hope that our vaccine, developed using an innovative approach to recombinant protein vaccine technology, may have a special role in adolescent vaccination based on parents’ and caregivers’ familiarity with protein-based vaccines used in other disease areas,” he added.

The FDA granted emergency use for adolescents after the company said its trial of 2,247 adolescents showed a primary efficacy of 78 percent. 

But Novavax conducted the trial last year, when the Delta variant was predominantly circulating in the United States. The White House has continued urging Americans to get vaccinated and boosted amid the spread of the BA.4 and BA.5 subvariants of omicron, but questions remain as to how the mutations could impact the vaccine’s efficacy.

The FDA authorized Novavax’s vaccine for adults last month, which was followed by the CDC’s blessing nearly a week later.

White House coronavirus response coordinator Ashish Jha said on Wednesday that regulators are expected to approve updated COVID-19 vaccine doses in “a few short weeks” for everyone over the age of 12. The shots are designed to target the two omicron subvariants currently circulating. 

Novavax’s COVID-19 shot helps prevent severe illness by injecting the human body with doses that contain the coronavirus spike protein. 

The company inputs genetic code that creates the spike protein into an insect virus, which replicates after infecting moth cells. The manufacturer then purifies and extracts the replicated spike proteins and injects them into humans.

The process only requires regular refrigeration, compared to Pfizer and Moderna’s mRNA vaccines that require storage in colder temperatures. Those vaccines contain genetic instructions for human cells to create the spike protein and defend against future infections.