The Centers for Disease Control and Prevention recommended last week that 5- to 11-year-olds receive booster doses if it’s been at least five months since their first two shots of the coronavirus vaccine. While this policy simplifies federal guidance — everyone 5 and older is now recommended to receive at least one booster — it doesn’t answer the pressing question on many parents’ minds: Should their child receive the booster now, or wait until the fall?
The answer is not straightforward, and the CDC’s blanket recommendation does not adequately address the nuances of boosting younger children.
On the one hand, there is growing evidence that the inoculations should be three-dose vaccines. Across all age groups, effectiveness against symptomatic infection after two doses wanes. In adults, effectiveness against severe illness also decreases over time. That effectiveness is restored after a third dose.
In studies of the 5- to 11-year-old age group, too few vaccinated individuals became severely ill to conclude that a third dose would further reduce hospitalization or death. However, a third dose substantially increased antibody levels, which, in all other age cohorts, correlated with protection against severe illness.
If these vaccines are meant to be three-dose vaccines anyway, one could argue the CDC might as well recommend the booster across the board to reduce confusion. Interestingly, an internal CDC work group initially proposed alternate language: That people ages 12 and over “should” receive the booster but that children ages 5-11 “may” get it. Ultimately, CDC’s external advisers chose “should” over “may” for younger kids, in large part to align the recommendation with other age groups.
I understand their rationale, but this “should” recommendation is not at the same level of certainty as other vaccine guidance. It’s clear that all adults should receive their first booster. Adults need at least three doses for optimal protection against severe disease, especially against the omicron sub-variants. It’s also clear that children need their primary series of two doses; 87 percent of children hospitalized during the omicron wave were unvaccinated.
But we don’t have a study that shows a third dose is needed for 5- to 11-year-olds to reduce severe illness. A third dose decreases their risk of symptomatic infection, but that protection is likely short-lived, on the order of weeks to months. If we’re saying younger kids should get vaccinated now, what happens if their immunity decreases after the summer? Should they all receive a second booster then, and at what frequency going forward?
That brings up the issue of timing. For older adults and those with serious medical conditions, additional boosters are needed now — during this new surge of infections — to prevent the most vulnerable from becoming seriously ill and dying. Such a rationale might also apply to younger children with underlying medical diseases, but parents of generally healthy kids might ask whether it makes sense to wait until the fall. By then, there might be data to show that immunity against severe disease is waning, making the case for the booster more compelling. There could also be variant-specific boosters available.
The CDC also leaves out another key consideration: According to their own estimates, based on blood testing for infection-induced antibodies, 77 percent of 5- to 11-year-olds have already contracted covid-19. Could a recent infection “count” as a booster?
Here’s what I would offer parents who want to tailor the CDC’s guidance to their own circumstances. Children with chronic medical conditions should opt for their first booster dose now. Immunocompromised children have already been eligible for their third dose. They are newly eligible for their fourth and should receive it five months after their third dose.
Kids who live at home with high-risk adults should probably also get their booster sooner rather than later, not primarily to protect themselves but the people they live with. Parents who have held off on certain activities for their children for fear of the coronavirus might also choose to boost sooner if it allows for a greater degree of normalcy.
On the other hand, kids who have recently been infected with covid-19 can probably hold off on their booster. The risk of reinfection is low in the short-term, and people with recent infection could safely delay their booster for at least three months. Families who are vaccinating to prevent severe disease rather than any illness may also make a reasonable decision to hold off for now.
At the end of the day, boosting this age group is tinkering around the edges, while other priorities are far more urgent. About half of adults eligible for their first booster have not yet received them, including 30 percent of those 65 and over. Less than 29 percent of 5- to 11-year-olds have received their first two doses. Public health efforts should prioritize increasing booster uptake for the most vulnerable and vaccinating the unvaccinated.