Finally, experts break the silence on J&J boosters

Early last month, I got my third COVID vaccine shot. I now realise this was overkill, and I'm fairly embarrassed about it, but at the time I felt like I was operating in an information vacuum.

Let me explain.

As I've written before, I participated in the Johnson & Johnson vaccine trial. Even though I initially got the placebo, the study offered me the opportunity to get the real thing weeks before I'd have otherwise been eligible, and I gratefully accepted. At the time, public health authorities were telling everyone to take the first shot you could get. I'm still glad I followed this advice; after gutting out the worst year of my life, I was terrified of getting COVID right on the brink of vaccine salvation.

But then things started to go wrong for J&J. At the end of March, news broke of problems at the Baltimore plant manufacturing the vaccine, and up to 15 million contaminated doses had to be scrapped. (Eventually around 60 million doses were thrown away.) In mid-April federal authorities called for a pause on the use of J&J shots because, in very rare cases, they were linked to a blood-clotting disorder.

By then, I'd had my vaccine for a month. But I was anxious about what the problems with J&J meant for boosters. When I got my inoculation, I knew the company was testing a two-dose regimen, and I thought it was likely that I'd end up getting a second Johnson & Johnson shot. Suddenly that seemed unclear.

In the following weeks, my uncertainty only grew. Because J&J has made up only a small fraction of vaccinations, there's been a paucity of information about how it's performed in the real world. In May, for example, when the Centers for Disease Control and Prevention said that vaccinated people don't have to wear masks indoors, it was primarily based on findings that the mRNA vaccines — those manufactured by Pfizer and Moderna — inhibit transmission. I had no intention of living my life more cautiously than people who'd got the mRNA shots, but I hated feeling like I was more vulnerable than them.

So in May, with vaccines plentiful where I live, I went to a nearby clinic and got a Pfizer shot. At that point, I reasoned, European countries were already combining the AstraZeneca vaccine, which uses roughly the same mechanism as J&J, with mRNA shots. A British study found no danger from mixing doses aside from increased side effects. And a Spanish study showed that when the AstraZeneca shot was followed by Pfizer, it seemed to trigger a more potent immune response than two doses of AstraZeneca did.

No one at the clinic asked if I'd already been vaccinated. Still, I felt that I was doing something sneaky and disreputable, and not just because it's unfair that Americans have such a glut of doses. In general, I don't think people like me, with no medical expertise whatsoever, should ignore expert guidance on vaccines because "I've done my own research" on the internet.

But the experts weren't telling people who'd gotten J&J much of anything. I reached out to a couple of high-profile physicians and scientists, but they didn't answer me, perhaps out of reluctance to provide untested medical advice.

Some other people were quietly doing the same thing I had. Right after getting the Pfizer shot, I called the J&J trial to confess, in case the people running it needed me to drop out. The person I spoke to said that while it wasn't ideal, I should keep participating and that I wasn't the only volunteer who'd gone out and gotten a second vaccine.

The evidentiary void around J&J seemed to grow more frightening with the spread of the delta variant. Previously, data from Britain had shown that a single dose of either Pfizer or AstraZeneca provided pretty good protection against COVID infection. With delta, single-dose protection went way down, to around 35%.

For weeks, no one knew what that meant for the J&J vaccine. Angela Rasmussen, a virus expert at the Vaccine and Infectious Disease Organization at the University of Saskatchewan, had the Johnson & Johnson shot and has been hearing from people who'd also gotten it and were scared.

"I really don't blame people; they keep hearing all this stuff about two shots, two shots, delta, you need to be fully vaccinated," she told me earlier this week. "And nobody's really saying anything about Johnson & Johnson." Many people, she said, "feel that they've been left behind because there really isn't any new information coming out about it."

On June 21, Rasmussen decided to get a Pfizer booster. At around the same time, Michael Z. Lin, a neurobiologist and bioengineer at Stanford, wrote a Twitter thread arguing that the CDC should issue guidance on mRNA boosters for people who'd received J&J. A couple of days later, Andy Slavitt, until recently a senior adviser to President Joe Biden's pandemic response team, put out an episode of his podcast titled, "The Delta Variant Question No One Will Answer," addressing those who'd received Johnson & Johnson and were wondering about getting another shot. He was equivocal: Either wait for the data or "go ahead and take a Pfizer or Moderna shot."

I wish I'd heard these voices earlier, because by then I'd already gotten two Pfizer shots. When the clinic scheduled my second appointment, I wasn't sure whether to return for it. I'm still not sure why I did. Mostly, at a time when no one was talking about J&J boosters, I didn't want to be an anomaly. I wanted the full Pfizer course because I didn't want to worry about whether new findings about mRNA effectiveness against the variants applied to me.

Nothing bad happened, but the experts I spoke to said that the third shot was unnecessary and that there's a point after which too much immune stimulation can be harmful. "There's no pressing reason to go beyond a single RNA booster," Lin told me.

Indeed, there may be no reason to get a booster at all. On Thursday evening, with discussion of boosting J&J all over the media, Johnson & Johnson released data showing that its vaccine retains most of its effectiveness against the delta variant. "Booster shots seem unnecessary, at least for now," The New York Times reported.

The news from Johnson & Johnson didn't change Lin's thinking. As he sees it, even before the delta variant, J&J wasn't as effective as the mRNA vaccines, which makes him apprehensive about breakthrough infections. And because delta is more transmissible than previous variants, those who do have breakthrough infections could be more likely to infect others.

No one I spoke to had any second thoughts about the message, during the early part of the vaccine rollout, to take the first shot you can get. When vaccines were in short supply and the virus was surging, it made sense. But now that mRNA vaccines are abundant in this country, the situation has changed.

It would be nice to have guidance on this from the CDC, but we shouldn't expect it anytime soon. In the absence of data, Slavitt said, it would be irresponsible for the CDC to make a recommendation. "People want the science to tell us exactly what to do," Slavitt said. "When we say, 'Follow the science,' the reality is, the science doesn't always know."

So, as with many other aspects of this pandemic, people have to figure things out for themselves. Slavitt said one of his sons was vaccinated with Johnson & Johnson and is planning to get an mRNA booster. But, he adds, people who do the same should know they're doing it at their own risk.

The need to make decisions with imperfect information "isn't uncommon, particularly in a situation where you've got a novel virus," Slavitt said. "Eventually, that answer will be known. Of course, people don't like to be in the uncomfortable zone before we know the answer."

I'm glad that people with expertise are finally weighing in. I just wish this conversation had gone public a few weeks sooner.

This article originally appeared in The New York Times.