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J&J vaccine pause a sign of ‘super cautious’ health agencies

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Gillian Smith

Federal health agencies have recommended pausing the use of Johnson & Johnson’s COVID-19 vaccine after six people developed blood clots within two weeks of receiving the one-shot vaccine.


Cynthia Leifer

Cynthia Leifer

Associate Professor of Immunology

Cynthia Leifer, associate professor immunology at Cornell University’s College of Veterinary Medicine, is an expert on molecular biology and cell biology, and how that area of science is important in developing vaccines. She says the pause is a sign that health agencies are taking appropriate precautions.

Leifer says:

“It is important to remember that blood clots are a common occurrence in those who contract COVID-19, but blood clots due to the vaccine are a very rare occurrence – six people out of 6.8 million people who received the J&J vaccine. However, if six is more than we would expect in any population of 6.8 million people, no more people should get that vaccine. A pause gives the safety committees a chance to review the data and make a decision. Those people who have received the J&J vaccine should monitor themselves, and if they don’t feel right, speak to their doctor out of an overabundance of caution.

“Clinical trials could not have detected this rare event, and the pause means that our agencies in charge of safety are being super cautious, as they should. We need to wait for more information to determine if this is a real adverse outcome and if it is, the fact we were able to detect this problem and halt the use of the vaccine shows that the ongoing safety analysis is working to detect these types of events as early as possible.

Professor in Cornell University’s Department of Government

Sarah Kreps

Professor of Government

Sarah Kreps , government professor at Cornell’s College of Arts and Sciences, surveyed nearly 2,000 American adults on issues regarding their willingness to get a vaccine. Barely half said they’d get the vaccine if its efficacy was similar to the annual flu shot, falling short of the 70% needed to achieve herd immunity.

Kreps says:

“The FDA has approved three vaccines that are all safe and highly effective against COVID-19.

“A generous interpretation of the FDA and CDC’s decision to pause the Johnson and Johnson vaccine would suggest an effort to maintain vaccine confidence over the long term. Our research suggests that it’s likely to have the opposite effect and contribute to greater vaccine hesitancy. Outlier cases capture a disproportionate amount of public attention. Fears that clinical trials were small and rushed as well as inflated concerns about the severity of vaccine side effects are highly correlated with unwillingness to vaccinate."

Douglas L. Kriner

Professor of Government

Doug Kriner, government professor at Cornell’s College of Arts and Sciences, has surveyed nearly 2,000 American adults on issues regarding their willingness to get a vaccine. Barely half said they’d get the vaccine if its efficacy was similar to the annual flu shot, falling short of the 70% needed to achieve herd immunity.

“While government scrutiny of adverse events should continue, regulators should be more careful in weighing not just the risks of a vaccine – the likelihood of clots appears to be no greater than in the general population – but also the risks of not vaccinating – the vastly higher risk of dying or suffering severe symptoms from COVID-19. Regulators should be aware that decisions and how they are communicated to the public will adversely influence vaccine confidence, already tepid among some demographics. It is essential that they redouble their efforts to publicly affirm the high degrees of safety and efficacy of the vaccines."

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