Moderna’s COVID-19 vaccine is effective in infants, toddlers, and preschoolers, the company announced Wednesday. If regulators approve it could lead to the possibility of finally starting vaccinating the youngest children by summer.

Moderna stated that it will ask European and American regulators to approve two small-dose shots for children under 6. Moderna also wants to see larger-dose shots approved for older children and teenagers in the U.S.

Only 18 million children below 5 years old are eligible for vaccination in the United States. Pfizer, a competitor, currently offers child-sized doses to school-age children as well as full-strength shots to those aged 12 and over.

Parents waited anxiously for protection for their children, but were disappointed by setbacks and confusion over which shots might work when. Pfizer is now testing smaller doses of vaccine for children younger than 5 years old, but added a third shot to the study after two failed to prove sufficient. These results will be available by April 1.

In an interview before Moderna released its findings, Dr. Bill Muller, a Northwestern University investigator, stated that vaccination of the youngest children “has been somewhat a moving target in the last couple months.” “There is still, I believe, an urgency to try and get that done as quickly as possible,”

The dose tested should be smaller for children younger than 6 years old. Moderna stated that a quarter of its adult dose worked well for children under 6.

Moderna recruited approximately 6,900 children to participate in a study on 25-microgram doses. The company released a press release saying that after just two shots, children developed the same virus-fighting antibodies as adults.

Moderna stated that the small doses of vaccine were safe and that the side effects were minor, similar to those seen with other pediatric vaccines.

Moderna will submit the data to FDA. The FDA regulators will then debate whether they are willing to allow emergency use of small doses of medication for infants. The Centers for Disease Control and Prevention will then decide whether they should be recommended.

Although COVID-19 is generally not as dangerous for children as it is for adults, some people do get very sick from it. According to the CDC, around 400 children under 5 years old have died of COVID-19 since its inception. Children were particularly affected by the omicron variant, which saw children under five hospitalized at higher rates that at the peak of previous delta surges, according to the CDC.

Although COVID-19 vaccines don’t protect against the omicron mutation as well as earlier variants, they offer strong protection against severe illnesses.

Moderna reported the same trend in the trial with children younger than 6 years, which was conducted during the omicron spike. The vaccine was effective in preventing infection in infants up to the age of 2 but not in preschoolers.

Moderna also stated Wednesday that it will request the Food and Drug Administration for larger doses to be cleared for older children.

Moderna’s vaccine is not allowed to be administered to children under 6 years old in other countries. The U.S., however, has restricted its use to adults. Moderna’s request to expand its vaccine to 12- and 17-year-olds was rebuffed for months.

Wednesday’s announcement by the company stated that it has additional evidence and is updating its FDA application to teen shots. It also requested a green signal for 6-to-11-year-olds.

Moderna claims that the original adult dose, two 100-microgram shots, is safe and effective for 12- to 17-year olds. It’s half of the adult dose for elementary-aged children.

The FDA did not rule on Moderna’s request for teen shots due to concern over a rare side effect. After receiving the Moderna or Pfizer vaccines, heart inflammation can sometimes occur in teenagers and young adults. This is mostly a male issue. Moderna vaccines are being scrutinized more closely than Pfizer because they contain a much higher dose of the vaccines.

This risk is also linked to puberty. In Canada, Europe, and elsewhere, Moderna vaccines were recently extended to children as young as 6.

Muller, from Northwestern, stated that “that concern hasn’t been seen in the smaller children.”