OPINION — Two claims about COVID-19 vaccines and pregnancy are moving through the country this week, and the reflex is to pick a team. One of them is arithmetically false. The other is documented in writing. Both things are true at the same time, and an honest reading of the record has to say so.
Start with the number, because it is the easier of the two. The claim that 82% of vaccinated women miscarried comes from a reworking of a 2021 New England Journal of Medicine paper reporting outcomes from the Centers for Disease Control’s v-safe pregnancy registry. That paper counted 104 spontaneous abortions among 827 completed pregnancies, a rate of 12.6%. Critics kept the same 104 losses but divided them by only the 127 completed pregnancies among women vaccinated before 20 weeks. That produces 82%.
This is not a reanalysis. It is a broken denominator.
