CNN
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Last week, the US Food and Drug Administration authorized the bivalent Covid-19 booster for children 6 months to 5 years old. The U.S. Centers for Disease Control and Prevention has since recommended the booster, and now everyone 6 months and older can get the updated coronavirus vaccine, except for children who got three doses produced by Pfizer/BioNTech.
Which young children are now eligible to receive the booster? What if children have not started or completed the full series – are they now receiving the updated booster or the original monovalent vaccine? Can parents and guardians choose between the updated reminder and the original snapshot? What are the possible side effects ? What if the children already had Covid-19? And which families should consider the updated booster now and who could wait?
To help us answer these questions, I spoke with Dr. Leana Wen, CNN medical analyst, emergency physician, public health expert, and professor of health policy and management at George Washington University Milken Institute School of Public Health. She is also the author of “Lifelines: A Doctor’s Journey in the Fight for Public Health” and 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 the Pfizer or Moderna vaccine are now eligible to receive the booster?
Dr. Leana Wen: There are two vaccines licensed for young children: Moderna and Pfizer. For the younger age group, the Moderna vaccine was designed to be a two-dose primary vaccine, while the Pfizer version was designed to be a three-dose primary vaccine. This means that young children are considered to have completed their primary series if they have completed two doses of the Moderna vaccine or if they have completed three doses of Pfizer.
As a reminder, there is now a bivalent booster available for older children and adults. This combines the original vaccine (also called monovalent) with a vaccine that specifically targets the BA.4 and BA.5 Omicron subvariants. Since Omicron subvariants make up virtually all new infections, the hope is that bivalent booster will provide better and more directed protection.
What federal health officials have now said is that children 6 months to 5 years old who received both doses of the original Moderna vaccine can get the updated bivalent vaccine – if it has expired. at least two months since they completed the primary vaccine series.
For children who have received the Pfizer vaccine, the instruction is a little different, because the first series already has three doses. Federal health officials said children 6 months to 4 years old who have not yet completed their three doses of the vaccine can receive the third dose as a bivalent vaccine. Let’s say a child started this series and received one or two doses of Pfizer’s original vaccine. The third dose can now be the updated booster.
CNN: What if kids haven’t started or completed the full series, are they now getting the updated booster or the original monovalent vaccine?
Magnifying glass: The answer is different for Moderna vs Pfizer. For Moderna, the main series is two doses, so a child must complete the initial two injections with the original formulation. The booster — the third dose — is the bivalent vaccine. For Pfizer, the first series is three doses. The first two doses should still be the original formulation, but the third injection is now the bivalent vaccine.
CNN: What about young children who have received three doses of the Pfizer vaccine? Are they eligible for a fourth dose?
Magnifying glass: No. The FDA explicitly states that children 6 months to 4 years old who have completed their primary three-dose series with the original Pfizer vaccine are not eligible for a fourth injection of the bivalent booster. Indeed, the first series of three doses of vaccine should still offer strong protection against serious illnesses in Omicron. This recommendation will be reassessed as new data becomes available.
CNN: Can parents and caregivers who have not completed the Moderna primary series choose the bivalent vaccine as a second dose?
Magnifying glass: No. The FDA clearance for the adult primary series for Moderna – both doses – is for the original monovalent vaccine. Similarly, there is no choice for which vaccine formulation is given as a Pfizer booster in adults. Only the bivalent booster is available as a third injection, not the original monovalent, which is always given in doses one and two. This reflects the authorization given for adults – the primary series is the monovalent vaccine, with the only booster for Pfizer and Moderna for adults being the updated booster.
CNN: What are the possible side effects of the updated recall?
Magnifying glass: Children who receive the updated booster are expected to have the same types of side effects as the original vaccines. These side effects tend to be mild and short-lived, usually disappearing within the first 24 hours after inoculation. Side effects may include pain and swelling at the injection site, fatigue, irritability, drowsiness, headache, muscle aches, and sometimes fever. Many children experience no side effects. The risk of serious side effects, such as myocarditis (an inflammation of the heart muscle), should be extremely rare in this younger age group.
CNN: What if the children already had Covid-19?
Magnifying glass: People who have had Covid-19 can wait three months until they have recovered from the coronavirus to receive another dose of the vaccine, according to the CDC. They probably have very good protection against infection during this time.
Numerous studies have shown that hybrid immunity – recovery from Covid-19 combined with vaccination – confers very strong protection, arguably even more so than vaccination and boosters alone. In my opinion, I think it can be argued that if a young child has had the primary series and has already had Covid, they could wait to get another booster dose. This is especially true if they have had Covid recently, within the past year. To my knowledge, no research shows an additional benefit of boosters for young children who have recently had a Covid-19 infection and who have received their primary vaccinations.
CNN: Which families should consider the updated recall now and who should wait?
Magnifying glass: First, I think it’s important to point out that the uptake of the primary series of Covid-19 vaccines in young children is very low. According to the CDC, less than 5% of children 5 and under are fully immunized. This means that we are referring to a very small group of children newly eligible for the updated boosters.
There is one group that I would definitely recommend to get the updated booster. This is the group of children who received their first or first two doses 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; they should complete the primary series, and it’s a bonus that the third dose is updated to target Omicron.
For children who have received both doses of the Moderna vaccine, I think the decision-making is different and will depend on the families’ individual circumstances. Some families are very concerned about Covid-19 infection. Perhaps their child has underlying medical conditions, or lives with someone who is elderly, immunocompromised, or otherwise highly vulnerable to the severe consequences of Covid-19. Perhaps the family will soon welcome a newborn, and this baby will be particularly vulnerable to infection with the coronavirus. I think it is reasonable to decide that since Covid-19 cases are increasing, now is the time to offer their young child the updated reminder.
I also think it is reasonable to wait. My children (ages 2 and 5) received the Moderna vaccines over the summer. They are eligible to be boosted, but I abstain because the protection they have against serious diseases remains strong. The booster will provide additional protection against symptomatic infection, but this effect is likely to be short-lived, according to a June study.
To be clear, I think it’s crucial that the elderly and vulnerable receive the updated reminder. I also think it’s generally a good thing that people can choose the booster if they want to, because there are compelling individual reasons for different households.
Parents and caregivers who have questions should consult with their pediatrician to decide on the best course of action for their family’s specific circumstances. Finally, families whose children have not yet received Covid-19 vaccines should consider starting, especially if their children are not known to have had Covid-19.
