If your child or teen is due for a Covid booster, they may now be eligible for an updated vaccine formulation, known as a bivalent booster, which could be available as soon as next week.

The Food and Drug Administration (FDA) recently authorized Pfizer-BioNTech's bivalent booster for kids age 12 and up, and Moderna's bivalent booster for those 18 and up. An advisory committee for The Centers for Disease Control and Prevention (CDC) approved the shots in a 13 to 1 vote on Thursday.

To help ward off a potential fall or winter surge in case numbers, both Pfizer-BioNTech and Moderna have updated their Covid vaccines to add an Omicron BA.4/BA.5 spike protein component to the current vaccine composition. 

The updated shots will be available for those who last received a booster shot or completed their initial dose series two months ago.

The Centers for Disease Control and Prevention (CDC) has recently published a planning guide for physicians to roll out the boosters, to help ensure easy access for families. For kids under 12, the CDC expects boosters to be available “within a short time” following authorization for older kids. 

The current vaccine formulations are still highly effective at preventing severe disease from Covid, but are significantly less effective at protecting against symptomatic illness, given that the virus has mutated so much since vaccines were first issued. The hope is that a single-dose booster this fall will offer more expanded protection against the Omicron subvariants BA.4 and BA.5. 

Per the most recent CDC data, 88.7% of all cases are attributable to BA.5, and the majority of the remaining cases are due to BA.4. But does your child need one, and how can you know if they are eligible? We're answering your questions here.

Related: What parents need to know about BA.5, the Omicron subvariant

What is a bivalent booster?

A bivalent booster is a vaccine formulation that helps the immune system mount an immune response against two different antigens, like two different strains of the same virus. Bivalent Covid vaccines offer protection against both the original virus SARS-CoV-2 and the Omicron subvariant.

Just like the original vaccines, the boosters have a high safety profile, and the boosters are manufactured using the same process as the original (monovalent) vaccines.

“The updated COVID-19 boosters are formulated to better protect against the most recently circulating COVID-19 variant,” CDC Director Rochelle P. Walensky, MD, MPH, said in a press release. “They can help restore protection that has waned since previous vaccination and were designed to provide broader protection against newer variants. This recommendation followed a comprehensive scientific evaluation and robust scientific discussion.” 

How do I know if my child will be eligible for a booster? 

If your child over 12 has received a primary vaccine series and/or a booster, the updated FDA guidelines state that they could be eligible for a single-dose booster once it has been at least 2 months since the last dose of their primary series or their last booster.

Kids ages 5 to 11 are still eligible for a single booster shot of the original monovalent vaccine if it has been at least 5 months since completing their initial series, but this age group isn't able to get the bivalent booster just yet.

To date, about 60% of adolescents ages 12 to 17 are considered to be fully vaccinated, which means having completed a primary vaccine series. Just 30% of kids ages 5 to 11 have done so. For kids under 5, the rates are even lower: Only 3% have received at least one vaccine dose as of July 2022. 

Related: CDC recommends Pfizer Covid booster shots for children 5 to 11 years old 

Will there be a fall or winter Covid surge?

It’s possible. Per the surge trends we’ve seen over the past two years, there’s been a sharp increase in case numbers beginning in the colder months. 

Thankfully, BA.5 is not currently considered to be especially severe, but it is highly transmissible. The CDC notes that there is no evidence so far that BA.5 is more severe than other Omicron subvariants. That said, it is still causing hospitalizations to increase around the world, which could be an issue of when more people become infected, there tends to be a rise in hospitalizations. 

“The COVID-19 vaccines, including boosters, continue to save countless lives and prevent the most serious outcomes (hospitalization and death) of COVID-19,” says FDA Commissioner Robert M. Califf, MD, in a statement. “As we head into fall and begin to spend more time indoors, we strongly encourage anyone who is eligible to consider receiving a booster dose with a bivalent COVID-19 vaccine to provide better protection against currently circulating variants.”

Related: Having young kids might protect you from severe Covid, study shows 

What if my child recently had Covid? 

Most adults and kids are now walking around with some level of immunity to the coronavirus, whether that's from vaccines or infection. But how well that immunity protects you seems to be quickly waning. That means that yes, you or your child can get Covid more than once, even if you’ve been recently infected—and even if you’ve had a previous version of Omicron (which is likely if you've been infected since January 2022). 

Unfortunately, we're seeing many instances of repeat infections around the world, which suggests that the former thinking that prior infection gave you a natural immunity for up to three months may no longer hold when it comes to BA.5. 

Experts stress that there’s an abundance of evidence that boosters will protect against severe disease. Plus, there’s the consideration that the more people who are fully vaccinated, the less the vaccine is able to spread and eventually mutate, experts say.

Related: Got questions about the Covid vaccine for kids under 5? We’ve got answers

A version of this story was originally published on Aug. 19, 2022. It has been updated.