US pharmaceutical Pfizer and its German partner BioNTech on Monday announced positive results from trials of their Covid-19 vaccine in children age 5-11.

The Phase 2/3 trial showed “a favorable safety profile and robust neutralizing antibody responses,” said a joint statement by the firms.

The trial had a two-dose regimen of 10 micrograms administered 21 days apart, or one-third of the 30 microgram dose used for people 12 and older.

“Since July, pediatric cases of Covid-19 have risen by about 240 percent in the US – underscoring the public health need for vaccination,” Pfizer Chairman and CEO Albert Bourla said in the statement.

“We are eager to extend the protection afforded by the vaccine to this younger population, subject to regulatory authorization, especially as we track the spread of the Delta variant and the substantial threat it poses to children,” he added.

Ugur Sahin, BioNTech’s co-founder and CEO, said trial data will be submitted to regulatory authorities for school-aged children before the start of the winter season.

“The safety profile and immunogenicity data in children aged 5 to 11 years vaccinated at a lower dose are consistent with those we have observed with our vaccine in other older populations at a higher dose,” said Sahin, who grew up in Germany from a Turkish immigrant family.

Companies said they will share the data with the US Food and Drug Administration (FDA), European Medicines Agency (EMA), and other regulators as soon as possible.

The Delta variant has produced a surge of pediatric Covid cases, and with in-person school resuming and this fall and winter set to see more people spending time indoors, there has been a push to expand vaccination to school-age children.

Since December 2019, the pandemic has claimed over 4.69 million lives in at least 192 countries and regions, with almost 228.6 million cases reported worldwide, according to the US’ Johns Hopkins University. Vaccine doses administered total over 5.9 billion, it showed.