Will children require booster shots for Covid-19? It's too early to say.

Many parents are worried if their children will need booster doses as scientists scramble to answer important issues regarding the omicron strain of the coronavirus.

According to preliminary data from South Africa, the Pfizer-BioNTech Covid-19 vaccine appears to be less effective against the omicron form. Pfizer and BioNTech reported on Wednesday that their own lab findings suggest the initial two-dose vaccine may not be enough to prevent infection, though it may still protect against severe disease. According to the firms, a booster shot appears to provide good protection against the omicron variety.

However, when it comes to children, numerous medical and vaccine experts believe it's too early to tell if they'll require additional injections. They also noted that the delta version remains the most common in the United States.

"The hope is that, because kids have a stronger immune response to the vaccine in general, they should still be able to mount a pretty good vaccine immune response, at least in the early going, after they've gotten the second dose," said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine and co-director of the Texas Children's Hospital Center for Vaccine Development. "However, I believe there are still many unknowns. And whether or not a booster will be needed is something that could be in the works. But we won't know for sure until that information is provided to the regulators. So far, we haven't arrived."

In October, the Food and Drug Administration approved Pfizer's lower-dose Covid-19 vaccination for kids aged 5 to 11. The Centers for Disease Control and Prevention (CDC) updated its booster shot recommendations for adults last month, recommending that everyone over the age of 18 get a booster injection six months after their second Pfizer or Moderna shot or two months after their Johnson & Johnson vaccine.

Pfizer requested this week that federal authorities approve a booster shot of its vaccine for 16- and 17-year-olds. Dr. Simon Li, director of the division of pediatric critical care at Rutgers Robert Wood Johnson Medical School in New Jersey and associate professor of pediatrics at Rutgers University, expects a recommendation in the next two to three weeks. Li is a primary investigator in a Pfizer vaccination clinical trial for children at Rutgers University.

"Anyone who understands this knows that immunization is an excellent way for priming and preventing serious infection," Li said. "We know that's been the case for every version that's been released." And I'd be surprised if the same isn't true for the omicron variety."

Dr. Anthony Fauci, the government's top infectious disease specialist, said it's possible that youngsters aged 12 to 15 will require a booster shot, but that it might not be necessary during an interview on CNN last month. According to Fauci, children in that age bracket have strong immune systems, and "healthy, ripped teenagers have a far better and stronger immunological response" than older adults. He doesn't rule out the possibility that their immunization protection lasts longer than six months.

Li said the findings of vaccine trials he's seen agree with Fauci's opinion.

"That's kind of what we're finding, actually," he said, adding that the amounts required to elicit a significant immunological response in youngsters are far lower.

Meanwhile, regardless of a person's age, the most pressing question about booster injections, according to Hotez, is how long and how durable the original vaccine's protection is. He also stated that the delta form is still dominating in the United States and would likely remain so for the foreseeable future.

Shortening the period between a person's booster shot and their initial immunization isn't always better, according to Hotez. Getting a booster too soon, he explained, might not provide as big of a boost.

"In other words, waiting six months may result in a bigger increase in virus neutralizing antibodies than waiting four months," he explained.

Scientists are still attempting to figure out how harmful the omicron form is, and what role booster doses might play in safeguarding individuals.

"We don't know how virulent omicron is yet," Li explained. "We know it's very contagious because it's highly transmissible."

Children in the Pfizer experiment on which Li is working range in age from 6 months to 11 years old, and some are only now finishing their second doses, according to Li.

"Right now, they haven't even gone to talk about boosters," Li explained. "We haven't arrived yet."