Pharmaceutical company Pfizer and biotechnology company BioNTech said Friday they have requested to have their coronavirus vaccine licensed for children ages 5 to 11 across the European Union. If EU regulators agree, it would be the first opportunity for younger children in Europe to get immunized against COVID-19.

Pfizer and BioNTech said they submitted data to the European Medicines Agency, including late-stage results from a study testing their COVID-19 vaccine in more than 2,200 children ages 6 months to 11 years. The children received a lower dose than what’s normally given to adults.

The companies said in a statement that the results showed a “strong immune response” in the children and that the vaccine was also found to be safe. There are currently no COVID-19 vaccines licensed for use in children younger than 12 in Europe or North America; the ones made by Pfizer-BioNTech and Moderna are authorized for children 12 and older in the European Union.

Earlier this month, Pfizer and BioNTech asked the U.S. Food and Drug Administration to greenlight their vaccine for children ages 5 to 11.

Expanding vaccine availability to roughly 28 million more U.S. children was seen as another milestone in the fight against the virus and comes amid an alarming rise in serious infections in youngsters because of the extra-contagious delta variant.

In the United States, COVID-19 has killed at least 520 children so far, according to the American Academy of Pediatrics.

With much of Europe's adult population already immunized, many countries are seeing increasing outbreaks of the disease in children while schools are mostly open and operating with sometimes patchy guidance on mask-wearing and social distancing.

The World Health Organization has said that vaccinating children was not a priority because they are far less likely to develop serious disease or to die of COVID-19. The health agency has repeatedly urged rich countries to share their doses with poor countries instead of expanding domestic eligibility so the world's vulnerable populations can be immunized.