What to know about Covid-19 vaccines for young children

WASHINGTON • A panel of advisers to the US Food and Drug Administration (FDA) has unanimously voted to recommend Moderna's Covid-19 vaccine for children under six years old and Pfizer-BioNTech's for children under five.

Here are some important details to know about these two mRNA vaccines for this age group:

A Moderna has asked the FDA to authorise a two-dose regimen of its vaccine in children six months to six years old. The 25mg doses are given 28 days apart. Adults received 100mg per shot for their first two doses.

Pfizer and BioNTech are asking for a three-dose course of their vaccine for children aged six months to under five years.

The first two doses are given 21 days apart and the third is administered at least two months after the second. Each dose is 3mg, below the 10mg given to children aged five to 11 and 30mg for people aged 12 and older.

Both companies sought lower-dose versions for younger children to reduce vaccine side effects.

A Moderna's vaccine was estimated to be 50.6 per cent effective in preventing symptomatic infections among children six months to under two years, and 36.8 per cent effective in children aged two to six in a clinical trial of over 5,000 subjects.

It is not yet known how effective the Pfizer-BioNTech vaccine is at preventing infection in people under age five because of the low number of symptomatic Covid-19 cases among the children in its trial.

An early analysis based on 10 symptomatic Covid-19 cases suggested a vaccine efficacy of 80.3 per cent in this group. Once 21 children in the trial contract symptomatic Covid-19, the companies can finalise the vaccine's efficacy.

Both companies said their trials showed that the vaccines generated a similar immune response to those seen in older age groups.

A Neither vaccine has raised any serious safety issues in the trials.

Heart inflammation known as myocarditis and pericarditis has been found to be a rare side effect of the vaccines in young men, but there have been few cases reported in the US in children aged five to 11, and none in either trial for the youngest age group.

A Some children reported pain and swelling at the injection site after vaccination from both vaccines.

Pfizer's low-dose vaccine was generally better tolerated, with only slightly more participants who received the vaccine complaining of fevers, irritability or fatigue when compared with those who received a placebo. In the two-to-four age old, 33.7 per cent of participants who received their second dose of the vaccine reported one of these side effects, against 32.2 per cent who received placebo.

For Moderna's vaccine, 58.9 per cent of those aged three to five reported some type of reaction like fever, headache or fatigue after receiving their second dose, compared with 37.2 per cent of participants who received placebo.

A Covid-19 is generally milder in children than adults, but there have been more than 440 coronavirus deaths in the US among those under age five, according to the FDA.

Data has shown that in older children and adults, vaccines protect against hospitalisation and death, according to Dr Matthew Harris, a paediatric emergency medicine physician at Northwell Health in New York. People who had a Covid-19 infection and received a booster shot had the most protection against the virus, he said.

REUTERS