Public health officials are beginning to wonder whether the definition of “fully vaccinated” should be revised to include booster shots — to push people to have the fullest protection against Covid-19. But even if getting a booster is a good choice for most people, making them mandatory at offices, schools, restaurants and elsewhere could detract from efforts to make sure everyone gets the basic vaccine.
The idea of mandating boosters assumes that vaccinated but not boosted people can contribute to overwhelming hospitals, and that boosting appreciably cuts back on viral transmission. But it’s not yet clear that giving boosters to young, healthy people would affect the course of the pandemic in this way.
Paul Offit, the director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and a longtime opponent of the anti-vaccine movement, says the sick kids he’s seeing at his hospital are unvaccinated — though many are over age 12 and have long been eligible for a shot. Usually the parents, too, are unvaccinated.
If the goal is to prevent severe disease, hospitalization and death, he told me, mandating boosters won’t help. “This is so frustrating, this booster discussion,” he said. “I don’t think boosters will have a major impact on the arc of the pandemic.”
Omicron might change things, depending on what researchers learn about its transmissibility and ability to evade vaccines. But in the case of the dominant delta variant, there’s evidence that vaccines continue to offer some protection without boosters. For people who are over 65 or immunocompromised and thus have a high risk of being hospitalized or dying, boosters are important. But young and healthy vaccinated people are unlikely to land in the intensive-care unit with Covid.
That’s not to say boosters aren’t useful. They are, though they don’t all serve the same purpose, Dan Barouch, a Harvard Medical School researcher who designed the Johnson & Johnson shot, told me. Consider that the J&J vaccine is initially much less effective than the two-dose mRNA vaccines made by Pfizer and Moderna. These spark a bigger burst of antibody production, but their effectiveness wanes over time. The J&J vaccine doesn’t wane, so by eight or nine months after shots are given, all three end up in the same efficacy range.
The reason to get a second shot of J&J is to improve one’s protection against symptomatic Covid from about 75% to 95%. For the mRNA vaccines, the idea is to re-establish high protection.
Theoretically, mixing and matching might give people broader, more durable immunity. And to get the best effect from any booster, it helps to wait six months from first vaccination. The boosters should cause a burst of new B cells — which produce antibodies — but they won’t have as much effect if those B cells are still in an activated state from the initial vaccination, Barouch explained. By about six months, the B cells have reverted to their resting state, and a booster will cause them to multiply fast.
Some helpful data on the various vaccines comes from studies of the regular tests given to professional basketball players and others who work for the NBA. Their test results reveal how much virus infected people carry and the degree to which people’s vaccine-induced Covid antibodies wane over time.
In a study published last week, Stephen Kissler, an immunologist at Harvard, found that vaccinated people were less likely to pass the disease on to others. Kissler’s evidence backs up other studies on health care workers that had similar results by showing that vaccinated people carry fewer viable copies of the virus.
The NBA employees who received the J&J shot experienced many more breakthrough cases than did those who had mRNA vaccines. The data also showed that mRNA protection waned, but this was highly variable. Some people’s antibodies faded to almost nothing in six months, while others’ persisted at virtually full strength. But there was no discernible pattern to predict which people will experience waning.
All this means there’s good reason for most of us to get in line for boosters. They improve immunity and can probably help keep us from becoming very ill in the event of an omicron surge.
But a personal health choice is not the same as a public health mandate. Would mandatory boosters reduce transmission or hospitalizations generally? Paul Offit thinks the potential benefits are not worth interfering with the push to get shots to unvaccinated Americans, to get them to countries where people have had little access, and to build public trust in the basic vaccines — and possibly other public health measures if omicron turns out to be very dangerous.
After decades of confronting the anti-vaxxers, Offit understands the sociology of public trust. In this pandemic, too much trust has been squandered on unnecessary restrictions not based on evidence, from closing parks and beaches to putting checkpoints at state borders. Political leaders wanted to do something, but not everything they did helped.
In the face of the mysterious new variant, the temptation to appear useful is strong. Omicron is what led the Centers for Disease Control and Prevention to expand the booster recommendation to all adults. But Covid-19 has proved nearly impossible to predict. Making booster shots mandatory without powerful evidence of a community benefit could cost public trust just when it’s needed most.
Bloomberg
