US FDA says Pfizer Covid vaccine effective in kids under five

The US Food and Drug Administration (FDA) has said the Pfizer Covid vaccine is safe and effective in children under five, ahead of a meeting to weigh its authorization later this week.

Children under five are the only age group not yet eligible for vaccination in the United States and most countries, a pressing need since rates of hospitalization and death "are higher than among children and adolescents 5-17 years of age," the FDA said in a document posted on its website Sunday.

The agency has called a meeting of experts on June 15 to decide whether to recommend the Pfizer vaccine, given as three shots to children aged six months through four years, as well as the Moderna vaccine, given as two shots to children aged six months through five years.

Pfizer's first two shots are given three weeks apart, then the third is given eight weeks after the second. They are all dosed at three micrograms, as opposed to 30 micrograms the company gives those 12 and up, and 10 micrograms to those five and up, levels chosen to mitigate adverse reactions.

Both Pfizer and Moderna had previously posted their results in press statements, but the FDA then had to review the data in detail and carry out its own evaluation. It posted a favorable analysis about Moderna on Friday.

Its comments towards Pfizer also appear favorable, based on the levels of infection-blocking antibodies it evoked in trial participants, and a similar side-effect profile to higher age groups. The total trial population was around 4,500 children.

A preliminary estimate placed vaccine efficacy at 80.3 percent, but the FDA noted this was based on very few positive cases -- just 10, as opposed to the 21 sought for a more accurate figure.

There are some 20 million US children aged four years and under, or six percent of the population. If, as expected, the FDA-appointed experts recommend the two vaccines, then the matter will go to another committee convened by the Centers for Disease Control and Prevention for a final say.

White House officials last week said rollout of millions of shots at pharmacies and doctors' offices could begin as soon as June 21, following the Juneteenth holiday on June 20.

Of the total US Covid deaths, 481 have come in children under five, according to the latest official data. Obesity, neurological disorders and asthma are associated with increased risk of severe disease, "however, a majority of children hospitalized for Covid-19 have no underlying medical conditions," the FDA said.

Children can also go on to contract multisystem inflammatory syndrome in children (MIS-C), a rare but serious post-viral condition. Data on long Covid in children is sparse, but "a national survey in the United Kingdom found that among children ages two to 11 years who tested positive for COVID-19, 7.2 percent reported continued symptoms at 12 weeks," the document said.