The predicted and actual menstrual cycle lengths before and after vaccination was more significant among women who received two doses within the same menstrual cycle, with an average difference of 3.9 days.
The protection provided by a second COVID-19 vaccine booster was worse than that bestowed by an initial booster, with the shielding trending negative after a period of time, according to a new study.
Less than a month after the CDC marked the two-year anniversary of the first administered COVID-19 vaccine by telling Americans to get a bivalent booster, two peer-reviewed German studies have found that mRNA vaccines — the vast majority of the U.S. market — induce worse antibodies compared to traditional adenovirus vaccines.