By Jared S. Hopkins 

Blood-clot concerns surrounding Johnson & Johnson's Covid-19 vaccine could complicate the U.S. mass vaccination campaign, deterring people who are already hesitant and giving room for misinformation to spread, health experts said.

The concerns sparked government efforts to educate people about the rare but serious blood clots and authorities' recommendation to pause use of J&J's shot while the reports are investigated, Anthony Fauci, the government's top infectious disease expert, said Wednesday.

The U.S. Food and Drug Administration and U.S. Centers for Disease Control and Prevention issued the recommendation Monday, after reports that six women ages 18 to 48 developed blood clots and low-platelet counts following vaccination, and one of them died.

The agencies acted correctly to be upfront and transparent about the events, health experts said, but the public warning will add to difficulties persuading many people that the vaccines are safe and worth getting.

"If people are hesitant, this isn't going to make them any happier, at least in the short run," said Dr. Martin Blaser, director of the Center for Advanced Biotechnology and Medicine at Rutgers University and an investigator in the J&J vaccine's pivotal trial.

Hesitancy to get vaccinated has been among the biggest challenges for vaccination efforts, which are crucial to achieving the community-wide immunity needed to lift restrictions and allow a return to post-pandemic life.

Much progress overcoming the reluctance has been made since last year as researchers, community groups and religious leaders worked to educate people about the benefits of vaccines to counter misinformation.

Fewer people surveyed expressed hesitancy compared with most of last year, recent polls show. Just 17% of Americans in late March said they were taking a "wait and see" approach about whether to get vaccinated, a drop from 39% in December, according to a Kaiser Family Foundation survey.

More than 60% of people surveyed by the foundation said in late March they had either already been vaccinated or planned to do so.

Yet the polling indicates large percentages of people remain hesitant. People in the U.S. who are reluctant, skeptical or even opposed to taking a Covid-19 vaccine cite concerns ranging from safety to mistrust of drugmakers and the government.

"There is a real risk of people being more hesitant if they hear about side effects, and if they hear about a side effect that leads to a pause, " said Saad Omer, director of the Yale Institute for Global Health who studies vaccine hesitancy.

Dr. Fauci said people should be reassured that authorities are monitoring reports of potential side effects, even after authorization of the vaccines.

On Tuesday night, government officials held a call with local leaders and urged them to talk with members of their communities about why authorities have recommended pausing use of J&J's vaccine and how it is a part of efforts to ensure shots are safe, Dr. Fauci said.

The clot issue prompted the U.S. government to suspend administration of J&J's vaccine at its vaccination sites; many other sites scrambled to give people scheduled for inoculation a different shot.

The FDA expects within a matter of days to decide whether and how J&J's vaccine should be used. One option is limiting use of the shot to certain age groups or populations, as regulators have done with some shots for other diseases.

The longer regulators take to resolve the situation, the higher the risk that hesitancy will increase, said Heidi Larson, an anthropologist and director of the Vaccine Confidence Project.

"When there is uncertainty out there, people fill that space," she said. "It's fertile ground for misinformation."

Some people may end up preferring other vaccines because of the clot issue, which could create problems; the vaccines aren't being distributed on preference but rather on supply and storage capabilities of vaccination sites, said Emily Brunson, a medical anthropologist at Texas State University who studies vaccine hesitancy.

"If they felt they were getting the lesser vaccine or the riskier one, that could further erode trust," she said.

Health experts said health authorities were right to move quickly and the pause reflects the effectiveness of safety protocols. Allowing reports to continue without investigation, the experts said, would raise suspicions among people hesitant to get shots.

"In that kind of scenario, if there's a drip-drip of news, that hurts confidence more than a regulator that is taking a proactive approach," said Dr. Omer said.

Now, health authorities must double down on educating the public about the benefits of vaccination, health experts said.

Part of the message, they said, should be explaining that the chances of getting Covid-19 are far higher than the odds of getting the rare clots, which vaccine experts have estimated at around one in a million.

"We need to remember how problematic Covid is, how many deaths can come from Covid," said Dr. Walter Orenstein, associate director of the Emory Vaccine Center. "Those risks are far greater than the risks of this vaccine."

Brianna Abbott contributed to this article.

Write to Jared S. Hopkins at


(END) Dow Jones Newswires

April 14, 2021 14:57 ET (18:57 GMT)

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