Recently released data show that females in Idaho reported post-vaccination coronavirus infections at higher rates than females across the country.
Nine in 10 of the more than 190 COVID-19 vaccine breakthrough cases in Idaho, as of Thursday, were females. Officials first disclosed that trend on April 13. New Centers for Disease Control and Prevention data released April 26 showed that females accounted for 63% of the more than 9,200 vaccine breakthrough cases recorded in the U.S. Women are about 51% of the population.
Coronavirus infections after being fully vaccinated against COVID-19 are rare. They accounted for .05% of the more than 400,000 fully vaccinated Idahoans, as of Tuesday.
A slew of factors could explain why females report breakthrough cases at higher rates than males.
Experts are searching for answers now, Dr. Christine Hahn, Idaho's top public health researcher, told reporters on Tuesday. She suggested the divide could be a difference in reporting caused by women being more likely to seek health care than men. But, Hahn said sex-based immunity differences could also play a role.
"We don't really know" why women are reporting vaccine breakthrough cases at higher rates, Hahn said. But, "we absolutely do know that the vaccines affect men and women (differently)."
Hahn said an example is the extremely rare blood clots tied to Johnson & Johnson's one-shot. The CDC said: "nearly all reports of this serious condition, which involves blood clots with low platelets, have been in adult women younger than 50 years old." The CDC and Food and Drug Administration recently said the benefits of the J&J shot "outweigh its known and potential risks," adding that women under age 50 should be aware.
Earlier this month, the state's deputy public health researcher, Dr. Kathryn Turner, noted that health care workers — an industry that is predominantly female — were the first people to access vaccines in Idaho. This week, Turner said women account for a larger share of vaccinated people than do men.
A report last year by the Idaho Center for Nursing found that 86% of registered nurses in Idaho were female. Nationally, the U.S. Census Bureau said in a 2019 report that "women account for three-quarters of full-time, year-round health care workers."
"It would make sense that our vaccine breakthrough cases would be more frequently with females," Turner said.
Similarly, the director of clinical services at Eastern Idaho Public Health, Amy Gamett, said Thursday that the high proportion of women in nursing makes it "not surprising to see a higher number of females" reporting post-vaccination infections.