The new vaccines are monovalent ones targeting the XBB.1.5 strain, a subvariant of omicron. They are expected to be more effective against currently dominant variants compared with the bivalent vaccines released last fall.
That alone should be reason for people who are worried about covid to get the latest type of shot. It will also help boost their immunity against the virus, which wanes quickly. Data presented at the CDC’s meeting on Tuesday shows that the effectiveness of the bivalent vaccine against hospitalization declines from 65 percent in the first two months after the shot to just 22 percent by four to six months. Its effectiveness against intensive care admission or death was more durable, but it still declined from 69 percent to 46 percent.
Flu vaccines are reissued every year for the same reasons. In the spring, regulators and manufacturers predict which influenza variants are likely to be circulating later in the year. Vaccines targeting those strains are then produced for the fall, when their effectiveness would have the best chance of lasting through flu season.
Having coronavirus vaccines follow a similar annual cadence is sensible. Annual flu shots are already recommended to everyone 6 months and older, and about half of Americans get one every year. Doctors’ offices and pharmacies are already set up for a fall flu vaccination campaign, so adding a coronavirus shot makes sense from a messaging perspective.
Health-care providers are used to speaking to patients about flu shots. Now, they can advise patients to receive a coronavirus booster at the same time. For those 60 and older, providers can recommend getting a vaccine against the respiratory syncytial virus (RSV), too.
CDC staff presented convincing data that covid-19 poses risks for people of all age groups, including those who were previously healthy. Among 18-to-49-year-olds admitted to the intensive care unit with covid, 13 percent had no underlying medical conditions. Half of the children with covid who died in the hospital had no preexisting illnesses. Vaccination reduces not only the risk of these tragic consequences but also the risk of developing long covid.
Critics of the broad recommendation have argued that the benefit of updated vaccines is not equal across age groups. Such critics say the guidance should target those most vulnerable, as health authorities in Britain have chosen to do.
I am sympathetic to this argument. More than 88 percent of covid deaths have been among people 65 and older, yet only 43 percent of people in this age group received a bivalent booster. If the goal is to reduce deaths and prevent hospitals from being overwhelmed, health officials should focus outreach to older individuals.
Moreover, while the CDC has shown compelling data in favor of healthy young people getting a coronavirus vaccine, it is much less clear they need an annual booster. More than 96 percent of children have antibodies against the coronavirus through infection, vaccination or both. That immunity is probably sufficient to safeguard against severe disease, which is already extremely unlikely in this age group.
The booster will reduce infections, but this effect wanes quickly. Two months after completing the initial vaccine series, vaccinated children only had a 16 to 24 percent reduction in urgent-care visits compared with unvaccinated kids.
This does not come close to the effectiveness of other routine childhood immunizations. Polio vaccination, for instance, is 99 to 100 percent effective against paralytic polio. Research has also not shown that regular boosting will reduce the incidence of long covid. And while coronavirus vaccination is generally very safe, there is a small risk of myocarditis — most prominently among males 12 to 29 years old.
In an ideal world, a coronavirus booster would be recommended to everyone 65 and older and those with serious underlying medical conditions. People not in these higher-risk groups should be allowed to receive the shot, in consultation with their physician.
Those who had the coronavirus recently could opt to wait, since they still have robust protection. And adolescent males and young children who are already vaccinated could hold off, because the benefit-risk analysis is trickier.
I think most physicians — and the public — will use this individualized approach anyway. But if the CDC had made such a nuanced recommendation, it could have led to insurance companies denying coverage for vaccines. And individuals without a health-care provider to consult might defer vaccination, further exacerbating disparities.
At the end of the day, the CDC chose simplicity and expediency. There’s no guarantee this is the right strategy; it might need to be reconfigured in the future to protect those most vulnerable to the continuing threat of covid.
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