It’s been a week since the FDA and CDC lifted their pause on the use of Johnson & Johnson’s Covid-19 vaccine. The pause lasted only 11 days, but the damage has been done. The move destroyed public confidence not only in what could have been an important vaccination tool both at home and abroad, but possibly also in the entire vaccination endeavor. What were they thinking?
In imposing and then lifting the pause, both the CDC and FDA leadership stressed that safety was their priority. Unfortunately, that priority crowded out all other considerations, especially the particular benefits of the J&J vaccine. Everyone acknowledged that the health complications in question were extremely rare: blood clots in the brain (cerebral venous sinus thrombosis, or CVST) coupled with low platelet counts in six vaccine recipients (later upped to 15) out of more than 7 million doses administered. But in their zeal to protect the public, the agencies became practitioners of the precautionary principle.
The precautionary principle has its origins in environmental decision-making and regulations of the 1980s and 1990s. While it has many different formulations, its central tenets are that, in the face of uncertainty, we should take preventive action to limit harmful impacts of a proposed action, and that the proponent of the action bears the burden of proving its safety. In the context of medicine, the precautionary principle demands that we should restrict new drugs and treatments if there is uncertainty about harmful side effects.
Decision-makers applying the precautionary principle are particularly concerned about the irreversible results of their decisions, particularly deaths and permanent disability. Sometimes, we can postpone a decision until we have better information about the costs and benefits of an action. As environmental-economics literature has pointed out, there is an option value in delaying a decision that could carry irreversible costs, if we expect to receive additional information in the future.
Yet there is also a cost to deferring a decision: the forgone benefit over the time that the decision has been deferred, which needs to be balanced against the benefit of the improved decision. And just as costs can be irreversible, so too can forgone benefits. The J&J vaccine pause provides a good example.
J&J’s is the only Covid-19 vaccine available that can be given in a single dose. It is also transported and stored in regular refrigerators, in contrast to the ultra-cold freezers needed for the Pfizer and Moderna vaccines. These attributes make it the vaccine of choice for hard-to-reach populations like the homebound, the elderly, and rural residents who might otherwise go unvaccinated.
During the pause, many among these groups had to forgo the benefit of being vaccinated. Some undoubtedly contracted Covid-19. Some will likely go on to die—an irreversible cost. In addition, the pause undermined public confidence in the J&J vaccine, and possibly Covid-19 vaccines in general, which could result in many people skipping vaccination and thus additional infections, illnesses, and deaths.
An Economist/YouGov poll on perceptions of vaccine safety found that belief in the safety of the J&J vaccine plunged from 52 percent to 37 percent immediately after the April 13 pause, while belief that the vaccine was unsafe rose by half, from 26 percent to 39 percent. The latest poll by the same group, conducted two weeks after the pause began and a few days after it was lifted, found that public belief in the J&J vaccine’s safety has only partly recovered. Moreover, in the two weeks since the pause, daily vaccinations in the U.S. for all Covid-19 vaccines have fallen by 20 percent.
If this exacerbation of preexisting vaccine hesitancy persists, the costs will be irreversible. Contracting Covid-19 poses a much greater risk of death than the J&J vaccine. Moreover, people who don’t receive the J&J vaccine face a far greater risk of all blood clots, including CVST, by contracting Covid-19 than they do from taking the J&J vaccine. Since early in the pandemic, we’ve known that people with Covid-19, especially those who are severely ill, have an increased risk of blood clots, leading clinicians to administer prophylactic anticoagulation. University of Oxford researchers found that the likelihood of CVST in the two weeks after being diagnosed with Covid-19 was 100 times the risk in the general population without the disease and about eight times the incidence following the AstraZeneca Covid-19 vaccine, which, like the J&J vaccine, employs an adenovirus platform. There was also an increased incidence of other potentially fatal blood clots in the abdomen after Covid-19 diagnosis.
Ensuring the safety of new products, especially ones intended for wide use, is an important goal—but it is not the only goal. We are in the middle of the biggest communicable-disease pandemic in a century, one that has already killed millions. Vaccines are the only way to shorten it and save lives. We should hope that in the future, the CDC and FDA will abandon the precautionary principle and conduct a more realistic balancing of costs and benefits.
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