Today’s announcement that federal officials have recommended pausing use of the Johnson & Johnson COVID-19 vaccine might hurt efforts to encourage people to get vaccinated. But — critically — that doesn’t mean the federal officials shouldn’t have made the recommendation, says Melanie Kornides, an assistant professor at the University of Pennsylvania School of Nursing who studies why some people are hesitant to take vaccines.

“Some people are missing the message — they’re so worried about hesitancy, that they’re not seeing how important it is to address the safety, in order to make people feel less hesitant,” she says.

The Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) recommended the pause while they investigate six reports of rare blood clots in people who received the Johnson & Johnson vaccine. The specific illnesses were unusual: the patients had a rare type of blood clot in their brains and very low levels of platelets, a type of blood cell involved in clotting. Similar clotting disorders were seen in the AstraZeneca vaccine, which uses the same vaccine technology as Johnson & Johnson. This combination of clots and low platelets needs a different type of treatment than normal blood clots, and the federal agencies wanted time to look into the cases and tell doctors what symptoms to watch for.

“I think that they did the right thing,” Kornides says. “The worst possible thing that they could do would be — if they had a legitimate concern, which it seems like they did — to investigate it without announcing, which would make it seem like they were covering something up.”

Still, flagging a potential safety concern to the public could make some people more reluctant to get the vaccine, Kornides says. Even if it turns out the blood clots were not linked to the vaccine or that they were extremely rare, the pause might make people hold off on getting a vaccine. The biggest worry is for people who were already on the fence about the shots. Those people may now decide to wait longer to get their vaccine or be nudged toward turning one down.

The Johnson & Johnson vaccine was the shot of choice for the group of people that was on the fence — it’s only one shot and had fewer common side effects. “It’s going to introduce new fears for those people,” Kornides says.

It’s a bad time to lose ground with that group: in some states, supply of the COVID-19 vaccine has already started to exceed demand. In those areas, health officials and doctors are trying to encourage people to get vaccinated.

Luckily, there are two other vaccines available (the Pfizer / BioNTech and Moderna shots), and these safety issues have not been seen in the more than 100 million people who received them. People worried about the very rare blood clots could be convinced to get those instead. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, highlighted that point during a White House press briefing today. “There have been no red flag signals from those,” said Fauci.

From a messaging perspective, the pause could be communicated as a positive sign and an indication that the FDA is taking safety seriously. “They’re not hiding anything,” Kornides says. It shows that people can be confident that the system watches out for any problems, even rare ones. Fauci stressed in the press briefing that the investigation should be left to the health officials. “You want to make sure that safety is the important issue here,” he said. “We are totally aware that this is a very rare event. We want to get this worked out as quickly as we possibly can.”

It’s a good message, even if there’s a chance it might not win out in the back-and-forth around the COVID-19 vaccine. People may still be afraid of potential risks even if they know officials are monitoring them, Kornides says.

But ultimately, a personal touch may be more effective than public messaging. It’s now even more important for doctors and health officials to hear each person’s individual concerns about the shots and tailor their conversations accordingly, Kornides says. If someone is worried about the blood clots, for example, a doctor can explain the rarity of the reaction or encourage them to take one of the other vaccine types.

The FDA and CDC should continue to be transparent about the investigation, Kornides says. The risk of increasing hesitancy can’t be a reason for the FDA and CDC not to explain vaccine-related concerns. “They had to do this because this is the way that we monitor safety of vaccines,” she says. “Without doing this, you can’t say that it’s a transparent system.”

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