Pushing this association too hard and too quickly could also skew data collection. Health workers could narrow their clinical lens; women might scour themselves for symptoms, while men and other people who don’t identify as women “may not take the symptoms [of CVST] seriously,” Krutika Kuppalli, an infectious-disease physician and vaccine expert at the Medical University of South Carolina, told me. That bell could be especially tough to un-ring in a culture where masculinity is so often considered incompatible with sickness. “People want to appear strong and tough, men in particular,” Hernandez told me. “There are already social pressures to not complain.” Casting the clotting condition as a “female problem” too early means donning blinders. “That’s troubling for the objectivity of the investigation going forward,” Richardson, of Harvard, said. (There’s still a paucity of data on whether transgender, intersex, or nonbinary people, especially those who are on hormonal therapies, might be vulnerable to unique vaccine side effects.)
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If a clear sex or gender difference does emerge, nuanced messaging will be necessary. As coronavirus cases surge, the risk of taking the vaccine might still be relatively low, especially in parts of the country where the fragile Pfizer and Moderna vaccines are harder to store and administer. Restricting the vaccine to certain age or gender groups could seed equity issues, both in the U.S. and internationally, or trigger repeated rounds of sociopolitical fallout. Shapiro pointed to the HPV vaccine, which was initially targeted to adolescent girls. The shots are now recommended for children of all genders, but misperceptions of the early rollout stigmatized the mostly female preteens who signed up for the shots as promiscuous, and the sole bearers of disease.
The goal in the coming days and weeks, Pai told me, is to appropriately titrate expectations of risk—to address concerns, but also avoid sensationalizing them. Our understanding of the clots’ danger could shift quickly as more data are collected. The dangers implied by six cases of a rare clotting disorder out of the roughly 7 million Americans who have received the J&J shot is much lower than the risk implied by six cases within the smaller population of the 1.4 million vaccinees who are women under 50. But now that physicians know what to look for, the numerator in that ratio will likely change as well. More cases will certainly appear, spanning a wider range of genders, ages, races, and ethnicities. These shifting odds will be easier to communicate if our lens isn’t unnecessarily narrowed: Expanding the definition of an at-risk population is harder than paring it down.
The suspension might already seem frustratingly long to some; plenty of people have called it out as cowardly and unwise, and questioned why federal officials prolonged it. But nearly everyone I’ve spoken with this week has praised the move as prudent, during a time of great uncertainty about who’s most at risk. “Ideally, we find out over time which vaccines are best for which groups, and why,” Leana Wen, an emergency physician affiliated with George Washington University, told me. “That’s the positive way of seeing this—this is in part the kind of information we’re getting here.”