Last week, the U.S. Food and Drug Administration approved the bivalent Covid-19 booster shot for children ages 6 months to 5 years. The U.S. Centers for Disease Control and Prevention has since recommended the booster shot, and now anyone 6 months or older can get the updated coronavirus vaccine, except for children, who received three doses manufactured by Pfizer/BioNTech.
Which young children are now eligible to receive the booster shot? What if kids haven’t started or completed the full series – are they getting the updated booster or the original monovalent vaccine now? Can parents and guardians choose between the updated booster and the original recording? What are possible side effects? What if children already had Covid-19? And which families should be considering the updated booster now and who could wait?
To help us answer these questions, I spoke with CNN Medical Analyst Dr. Leana Wen, an emergency room physician, public health expert, and professor of health policy and management in the School of Public Health at George Washington University’s Milken Institute. She is also the author of Lifelines: A Doctor’s Journey in the Fight for Public Health and is a mother of two young children, ages 2 and 5.
CNN: Let’s start with what just changed in the recommendations: Which young children who received either the Pfizer or Moderna vaccines are now eligible for the booster?
dr Leana Wen: Two vaccines are approved for young children: Moderna and Pfizer. For the youngest age group, the Moderna vaccine was designed as a two-dose primary vaccine, while the Pfizer version was designed as a three-dose primary vaccine. This means that young children are considered to have completed their primary series when they have completed two doses of the Moderna vaccine or three doses of Pfizer.
As a reminder, there is now a bivalent booster for older children and adults. It involves combining the original (also monovalent) vaccine with a vaccine specifically targeting the BA.4 and BA.5 omicron subvariants. Since subvariants of Omicron account for virtually all new infections, there is hope that the bivalent booster will provide better and more targeted protection.
What federal health officials have said now is that children ages 6 months to 5 years who received both doses of the original Moderna vaccine can receive the updated bivalent vaccine — if it’s been at least two months since they received the primary vaccine series completed.
For children who have received the Pfizer vaccine, the guidance is slightly different as the primary immunization is already three doses. Federal health officials have said children ages 6 months to 4 years who have not completed their three doses of vaccine can receive the third dose as a bivalent vaccine. Let’s say a child started this series and received a dose or two of the original Pfizer vaccine. The third dose can now be the updated booster shot.
CNN: What if kids haven’t started or completed the full series – are they getting the updated booster shot or the original monovalent vaccine now?
Whom: The answer is different for Moderna vs. Pfizer. For Moderna, the primary series consists of two doses, requiring a child to complete the first two shots with the original formulation. The booster – the third dose – is the bivalent vaccine. At Pfizer, the primary series consists of three doses. The first two doses must still be the original formulation, but the third injection is now the bivalent vaccine.
CNN: What about young children who have completed three doses of the Pfizer vaccine – are they entitled to a fourth dose?
Whom: no The FDA specifically states that children ages 6 months to 4 years who have completed their three-dose primary series with the original Pfizer vaccine are not eligible for a fourth dose of the bivalent booster. That’s because the first series of three vaccine doses is still expected to provide strong protection against a serious illness from Omicron. This recommendation will be reassessed as new data become available.
CNN: Can parents and caregivers who have not completed Moderna’s primary series choose the bivalent vaccine as their second dose?
Whom: no FDA approval for the adult primary series for Moderna – the two doses – is for the original monovalent vaccine. Likewise, there is no choice as to which vaccine formulation is given as a booster dose for Pfizer in adults. Only the bivalent booster vaccine is available as the third injection, not the original monovalent, which will continue to be administered as doses one and two. This reflects the approval given for adults – the primary series is the monovalent vaccine, with the only booster for adults for Pfizer and Moderna being the updated booster.
CNN: What are possible side effects of the updated booster?
Whom: It is expected that children who receive the updated booster shot will experience side effects similar to those of the original vaccines. These side effects are usually mild and short-lived and usually subside within the first 24 hours after vaccination. Side effects can include pain and swelling at the injection site, tiredness, nausea, drowsiness, headache, muscle aches, and sometimes fever. Many children have no side effects. The risk of serious side effects such as myocarditis (inflammation of the heart muscle) is believed to be extremely rare in this younger age group.
CNN: What if kids already had Covid-19?
Whom: People who have had Covid-19 can wait three months until they recover from the coronavirus to receive another dose of vaccine, according to the CDC. They probably have very good protection against infection during this time.
Many studies have shown that hybrid immunity – recovery from Covid-19 combined with vaccination – offers very strong protection, arguably even more than vaccination and booster shots alone. In my opinion it can be argued that a young child who has had the primary vaccination and already had Covid could be waiting for another booster dose. This is especially true if they have had Covid recently in the last year. To my knowledge, there is no research showing an added benefit of booster shots for young children who have recently had Covid-19 infection and have had their primary vaccination course.
CNN: Which families should be considering the updated booster now, and who should wait?
Whom: First of all, I think it is important to point out that the uptake of the first series of Covid-19 vaccines among young children is very low. According to the CDC, less than 5% of children under the age of 5 are fully vaccinated. This means that we are referring to a very small pool of children who are newly eligible for the updated boosters.
There is one group that I would definitely recommend getting the updated booster. This is the group of children who received their first dose or two of the Pfizer vaccine. These children must complete their primary series. The third dose in this series is now the updated bivalent booster. There is no reason for the families of these children to wait; You should complete the primary series, and it’s a bonus that the third dose updates to target Omicron.
For children who received the two doses of the Moderna vaccine, I think the decision making is different and depends on the individual circumstances of the families. Some families are very worried about Covid-19 infection. Perhaps your child has underlying medical conditions, or you may be living with someone who is older, immunocompromised, or otherwise very vulnerable to severe effects of Covid-19. The family may be welcoming a newborn soon, and this baby is particularly vulnerable to coronavirus infection. I think it is reasonable to decide that it is time to give your young child the updated booster shot as cases of Covid-19 are increasing.
I think it makes sense to wait. My kids (ages 2 and 5) received the Moderna vaccines over the summer. They’re entitled to a boost, but I’m holding off because the protection they have against major illnesses remains strong. The booster will provide additional protection against symptomatic infections, but that effect is likely short-lived, according to a June study.
To be clear, I believe that getting the updated booster shot is crucial for older adults and those at risk. I also think it’s generally good that you can choose the booster if you want, as there are compelling individual reasons for different households.
Parents and caregivers who have questions should consult their pediatrician to determine the best course of action for their family’s specific circumstances. Finally, families whose children have not yet received Covid-19 vaccines should start doing so, especially if their children are not known to have had Covid-19.