Courtney Weyel puts COVID-19 vaccine into a syringe at Hartford Healthcare at Home before visiting housebound patients' houses. Yehyun Kim /
Hartford residents line up for COVID-19 vaccinations on April 1, 2021, the first day of eligibility for anyone 16 or older. The pop-up clinic inoculated 260 people with the one-shot Johnson & Johnson vaccine. Jacqueline Rabe Thomas /

The Johnson & Johnson single-dose vaccine’s use was suspended in Connecticut on Tuesday following recommendations from the Food and Drug Administration and the Centers for Disease Control and Prevention, leaving people wondering what it all means as the battle against the coronavirus pandemic continues.

Regulators are investigating the J&J vaccine after six women between the ages of 18 and 48 developed particular blood clots after receiving the shot. Those women also displayed low platelet counts. One woman has died, and another is in critical condition. Nearly seven million J&J shots have been administered nationwide.

Johnson & Johnson has acknowledged the reports and postponed its rollout in Europe. It is not clear that its vaccines caused the rare conditions and the fatality.

Scientific discovery can be messy and contradictory in real-time, and when the stakes are as high as life or death, it can be difficult to follow rapid developments carefully. Here’s a primer on what we know, what we don’t know, and what to expect next.

What do we know?

Six cases out of nearly seven million: “We’re happy that the number is not higher,” said Ulysses Wu, System Director at Hartford HealthCare. Nevertheless, a death has been potentially linked to the vaccine, and the CDC and FDA have acted out of what they term “an abundance of caution.”

The pause was put in place to allow the CDC to examine causality and risk and recommend treatment for the condition. “We expect it to be a matter of days for this pause,” FDA Acting Commissioner Janet Woodcock said at a press conference Tuesday morning.

If there is a relationship between the vaccine and this adverse reaction, contracting the clots and dying is likely to be extremely rare, experts say. But while the risk to an individual may be low, generally speaking, the unprecedented scale of the United States’ current vaccination effort — where 3 million shots are administered daily — means that even low-probability events can add up on a population level.

The CDC’s Advisory Committee on Immunization Practices has the challenge of assessing and weighing the risk of vaccination for individuals of different demographic groups against the morbidity and mortality risks posed by COVID-19. In general, the Johnson & Johnson vaccine has been shown to be effective in preventing severe illness and death from COVID-19.

What don’t we know?

Correlation is not causation — which means that though two events might have happened at the same time, one doesn’t necessarily cause the other. Seven million people is a lot, which means a number of confounding factors could be at play; when a country gives out a vaccine at that scale, it’s likely that some people will have complications unrelated to the vaccine.

What put the FDA and CDC on high alert was not simply the presence of blood clots in veins in the brain, which occur in 2-14 people per million, but the combination of those clots with low platelet counts, said Peter Marks, director of the FDA Center for Evaluation and Research. That pattern of clots and low platelets was similar to what European regulators have been investigating in the case of the Oxford/AstraZeneca vaccine, which uses similar biotechnology to the J&J vaccine. Preliminary research suggests a causal link between the AstraZeneca vaccine and rare blood clots.

If there is a causal link, it is also unclear whether certain demographic groups have more risk than others and how that risk might vary with age and gender, among other factors. In the case of the AstraZeneca vaccine, some European regulators have discouraged younger populations in particular from getting the shot.

“I believe that there are too few cases for us to make that determination for this particular vaccine,” Woodcock said. “We aren’t prepared at this time to single out any particular sub-group.”

Regulators are also developing recommendations for the treatment of the condition. While blood clots normally may be treated with heparin, a blood thinner, the CDC specifically cautioned against using that approach in this instance. At Hartford HealthCare, “we’re waiting for guidance,” Wu said. The hospital system has not received any reports consistent with the clotting or low platelet count described, said James Cordon, the chief clinical integration officer at Hartford HealthCare.

Where do we go from here?

For now, the state has suspended the use of J&J as it awaits federal updates. The federal government will not be sending J&J vaccines via the federal pharmacy partnership or to federally qualified health centers directly.

Health providers are encouraged to report any vaccine complications to Health and Human Services in the meantime.

The Advisory Committee on Immunization Practices is an independent scientific body that advises the CDC. It is scheduled to meet Wednesday to review the data; its meetings are public and will be broadcast online.

“We’re going to tell you what we know when we know it, and what you can do to protect yourself,” Anne Schuchat, principal deputy director of the CDC, said at a press conference Tuesday morning.

If you already got the J&J vaccine, do you need to worry?

Depending on when you got the vaccine, you might need to be vigilant.

“For people who got the vaccine over a month ago, the risk for them is very low at this time. For people who recently got the vaccine within the last couple of weeks, they should be aware to look for any symptoms,” Schuchat said.

Side effects to watch out for include “severe headaches, abdominal pain, leg pain or shortness of breath,” she added. These symptoms are distinct from the fever, fatigue and nausea that are common side effects of the vaccine.

What do you do if you have a J&J vaccine appointment scheduled?

“You should wait to hear from a provider about appointment cancelation before you assume that your appointment will be canceled,” said Deidre Gifford, the commissioner of the state Department of Public Health, at a press conference Tuesday. “If you do hear from a provider that your appointment is canceled, you can reach out to our vaccine assistance line, the 211 line, and they will be happy to assist you.”

Appointments scheduled via the state phone system will be for Pfizer or Moderna shots, she said. The phone number is 877-918-2224.

What about the other vaccines?

The Pfizer/BioNTech and Moderna vaccines use a different technology to confer immunity than the J&J and AstraZeneca vaccines do. The Pfizer and Moderna shots use mRNA, while the AstraZeneca and the J&J are adenovirus vaccines. That’s one of the reasons the United States looked to Europe’s experience with AstraZeneca in its response to the J&J vaccine.

The AstraZeneca vaccine has not received emergency authorization in the United States; only the J&J, Pfizer and Moderna vaccines have received that approval so far.

“We are not seeing these clotting events with low platelet counts in the other two vaccines,” Schuchat said.

For context, “there have been over 180 million doses of these vaccines administered,” Marks said.

In Connecticut, supply has heavily skewed towards the Pfizer and Moderna vaccines.

At the end of his press conference yesterday, Gov. Ned Lamont reminded residents yet to be vaccinated that they still have two safe and effective options at their fingertips, regardless of any CDC and FDA decision on the J&J vaccine. “You know, the biggest concern I have is that it gives people a reason to pause. I think it should give you a reason to go get vaccinated with mRNA.”

CT Mirror staff writers Mark Pazniokas and Jenna Carlesso contributed to this report.

Kasturi was CT Mirror’s data reporter. She is a May 2020 graduate of the Columbia Journalism School’s master’s program in data journalism and holds a degree in comparative literature from Brown University, where she was editor-in-chief of the student newspaper. Prior to joining CT Mirror, Kasturi interned for publications in India.

Leave a comment