However, absolute risks are small, with 11 excess venous thromboembolic events per 100,000 vaccinations<\/p>\n<\/h3>\n
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WEDNESDAY, May 19, 2021 (HealthDay News) — The rates of venous thromboembolic events, including cerebral venous thrombosis, are increased among recipients of the Oxford-AstraZeneca vaccine ChAdOx1-S, although the absolute rates are small, according to a study published online May 5 in The BMJ<\/em>.<\/p>\n Anton Potteg \u00a5rd, Ph.D., from the University of Southern Denmark in Odense, and colleagues conducted a population-based study involving all people aged 18 to 65 years who received a first vaccination with ChAdOx1-S from Feb. 9 to March 11, 2021 (148,792 people in Denmark and 132,472 in Norway). The general populations of Denmark and Norway served as comparator controls.<\/p>\n The researchers found that the standardized morbidity ratio for arterial events was 0.97 (95 percent confidence interval, 0.77 to 1.20) among 281,264 people who received ChAdOx1-S. The vaccinated cohort had 59 venous thromboembolic events compared with 30 expected events based on the incidence rates in the general population, corresponding to a standardized morbidity ratio of 1.97 (95 percent confidence interval, 1.50 to 2.54) and 11 excess events per 100,000 vaccinations. The rate of cerebral venous thrombosis was higher than expected, with a standardized morbidity ratio of 20.25 (95 percent confidence interval, 8.14 to 41.73). There were 15 deaths reported in the vaccine cohort compared with 44 expected.<\/p>\n “Those countries that delayed their own vaccination programs at a time of high transmission rates by declining to use available Oxford-AstraZeneca vaccines should know that their decision will have contributed to an increase in the number of avoidable deaths from COVID-19,” writes the author of an accompanying editorial.<\/p>\n Several authors disclosed financial ties to pharmaceutical companies, including those that make vaccines against severe acute respiratory syndrome coronavirus 2.<\/p>\n Abstract\/Full Text<\/a><\/p>\n