Last week, the US Food and Drug Administration approved a bivalent Covid-19 booster for children aged 6 months to 5 years. The US Centers for Disease Control and Prevention has since recommended the booster, and now everyone 6 months of age and older can get the modified coronavirus vaccine, except for babies made by Pfizer/BioNTech.
Which young children are eligible to receive the incentive? What if kids haven’t started or completed the entire series – just got the booster or the first monovalent vaccine? Can parents and guardians choose between the updated booster and the original shot? What are the possible side effects? What if children already have covid-19? And which families should consider the revised incentive now, and who can wait?
To help answer these questions, I spoke with CNN medical analyst Dr. Leanna Wen, an emergency physician, public health expert and professor of health policy and management at the 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 the mother of two young children, ages 2 and 5.
CNN: Let’s start with what just changed in the comments: Which young children who received the Pfizer or Moderna vaccine are now eligible to receive the boost?
Dr. Leanna Wen: There are two vaccines approved for young children: Moderna and Pfizer. For the younger 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. That means young children are considered to have completed their primary series if they have completed two doses of the Moderna vaccine or three doses of the Pfizer vaccine.
As a reminder, there is now a dual booster for older children and adults. This combines the original (also called monovalent) vaccine with a vaccine that specifically targets the BA.4 and BA.5 Omicron subunits. Since the Omicron subunits account for almost all new infections, the hope is that the bivalent booster will provide better and more direct protection.
Federal health officials now say that children ages 6 months to 5 years who received both doses of the original Modarian vaccine can receive the modified bivalent vaccine — at least two months after completing the primary vaccination.
For children who received the Pfizer vaccine, the instructions are a little different, because the primary series already includes three doses. Children between the ages of 6 months and 4 years who have not yet completed three doses of the vaccine can receive the third dose, like the bivalent vaccine, according to federal health officials. Let’s say a child starts this series and gets a dose or two of the first Pfizer vaccine. A third dimension may now be the improved incentive.
CNN: What if kids didn’t start or finish the whole series — they just got the booster or the first monovalent vaccine?
Wen: The answer to Moderna vs. Pfizer is different. For Moderna, the primary series is two doses, so a child needs to complete the first two vaccinations with the first prescription. Booster – the third dose – is a bivalent vaccine. For Pfizer, the main series is three sizes. The first two doses must still be the first formulation, but the third vaccine is now a two-dose vaccine.
CNN: What about young children who have completed three Pfizer vaccinations – are they eligible for a fourth dose?
Wen: No. The FDA clearly states that children ages 6 months to 4 years who have completed their three-dose primary series with the first Pfizer vaccine are not eligible for a fourth dose of the bivalent booster vaccine. This is because the first three doses of the vaccine series are still expected to provide strong protection against severe disease for Omicron. This advice will be re-evaluated as new data is released.
CNN: Can parents and caregivers who haven’t completed the primary Moderna series choose the two-dose vaccine as a second dose?
Wen: No. FDA approval for adults is the primary monovalent vaccine for Mordiana – the two doses. Similarly, in adults there is no choice as to which vaccine preparation is given as an incentive to Pfizer. Only the bivalent booster is available as a third shot, not the first monovalent, which is still given as one and two doses. This reflects the approval for adults – the original series is a monovalent vaccine, the only update for Pfizer and Moderna for adults.
CNN: What are the possible side effects of the updated stimulus?
Wen: Children who receive the modified booster are expected to have the same side effects as the original vaccines. These side effects are mild and short-lived, usually resolving within 24 hours of injection. Adverse reactions include pain and swelling at the injection site, fatigue, irritability, insomnia, headache, muscle pain, and sometimes fever. Many children do not feel any side effects. The risk of serious side effects such as myocarditis (inflammation of the heart muscle) is expected to be much lower in this young age group.
CNN: What if children already have Covid-19?
Wen: The CDC says that people who have had Covid-19 can wait up to three months before receiving another dose of the vaccine after recovering from the virus. Perhaps they have a very good defense against infection during this period.
Several studies have shown that hybrid immunity—combined with a vaccine for recovery from Covid-19—conveys the strongest protection, arguably more than vaccines and boosters. In my opinion, if a young child receives primary series and already has covid, he can expect to receive another dose of reinforcement. This is especially true if they have had Covid in the past year. To my knowledge, there are no studies showing additional boosters for young children who have had a recent Covid-19 infection and have received their primary vaccination.
CNN: Which families should consider the revised incentive now and who should wait?
Wen: First, I think it’s important to note that uptake of the first series of Covid-19 vaccines among young children is very low. According to the CDC, less than 5 percent of children 5 and under are fully vaccinated. This means that we refer to very young children who are eligible for current incentives.
There is one group that I would definitely recommend you find an up-to-date booster. This is a group of children who received the first one or two doses of Pfizer vaccine. These children must complete their primary series. The third in that series is just the updated bivalent booster. The families of these children have no reason to wait; They should complete the first tier series, and the third volume would be nice to update to target Omiron.
For children who have received two Moderna vaccines, I think the decision is different and depends on the family situation. Some families are very concerned about the Covid-19 infection. Perhaps their child has a chronic medical condition, or they live with someone who is elderly, immunocompromised, or otherwise more vulnerable to the serious effects of Covid-19. Perhaps the family will soon be welcoming a newborn, and that baby will be especially vulnerable to coronavirus infection. I think it’s reasonable to decide that now is the time to get your child up-to-date, as cases of covid-19 are on the rise.
I think it is reasonable to wait. My children (ages 2 and 5) received Moderna vaccines over the summer. They’re worthy of a raise, but I hold back because their protection against serious illness remains strong. The boost may confer additional protection against symptomatic infections, but that effect is likely short-lived, according to a June study.
To be clear, I believe that access to up-to-date incentives for elderly and vulnerable individuals is critical. I think it’s generally a good thing if people choose the incentive if they want to, as there are compelling reasons for different families.
Parents and caregivers should consult their pediatricians to determine the best course of action for their family’s unique circumstances. Finally, families whose children have not yet received Covid-19 vaccines should consider getting started, especially if their children are not known to have had Covid-19.