in the population to derive a better correlation on its incidence post vaccination.
Vaccination Effect
The cohort study evaluated the cases from January 1, 2001, to December 31, 2015, at Olmsted County, Minnesota using eMethods in the Supplement. The sex-and age-adjusted incidence rates were attuned to the 2010 US census population.
The incidence of CVST after Ad26.COV2.S vaccination was then estimated from February 28, 2021 (vaccine approval date) to May 7, 2021 using CDC Vaccine Adverse Event Reporting System (VAERS) data at days 15, 30, and 92.
It was found that 39 Olmsted County residents developed acute incident CVST from 2001 to 2015. A predisposing risk factor of venous thromboembolism such as infection, active cancer, or oral contraceptives (women) was present in almost 29 patients (74.4%) within 92 days before the event.
After 8,727,851 Ad26.COV2.S vaccine doses were administered on May 7, 2021, in the US, 46 potential CVST events were reported to VAERS, to have occurred within 92 days after vaccination.
Higher Incidence of CVST
The overall age- and sex-adjusted CVST incidence was found to be 2.46 and 2.34 per 100 000 person-years for females and males respectively. In addition, the overall incidence rate of post-Ad26.COV2.S vaccination CVST was 8.65 per 100 000 PY at 15 days, 5.02 per 100 000 PY at 30 days, and 1.73 per 100 000 PY at 92 days.
The rate was almost 5.1-times higher among females when compared with the pre-COVID-19 pandemic rates. However the exact reason for higher rates in females was unclear.
The study thereby suggests that the higher rates of these rare adverse effects of the vaccine must be considered in further preventing COVID-19.
Source: Medindia
