The incidence rates for both heart attacks and strokes (arterial thromboses) were lower after COVID-19 vaccination than before or without vaccination during the earlier years of the pandemic, according to a new study from England.
Heart attacks and strokes were up to 10% lower in the 13 to 24 weeks after the first dose of a COVID-19 vaccine. And post second dose, the incidence was up to 27% lower after receiving the AstraZeneca vaccine and up to 20% lower after the Pfizer/Biotech vaccine.1
This was a very large study involving nearly the entire English population with 46 million adults. And in terms of vaccination, over 37 million people received a COVID-19 vaccine, and were eligible for a second vaccine. 1The incidence rates for both heart attacks and strokes (arterial thromboses) were lower after COVID-19 vaccination than before or without vaccination, according to a new study from England.1
The results were published in Nature Communications.
Study Parameters and Takeaways
The British Heart Failure Foundation (BHF) Data Science Center and led by the Universities of Cambridge, Bristol and Edinburgh analyzed health records from 46 million adults in England between December 8, 2020 and January 23, 2022. The study involved nearly the whole adult population of England and the investigators compared the incidence rates of cardiovascular diseases after vaccination with the incidence before or without vaccination during the first 2years of the vaccination program.1
In addition to a reduction of arterial thromboses, venous thrombotic events also showed a similar result, especially in latter doses. “After second and booster vaccine doses, the reduction in incidence of composite venous thrombotic events was greater than after first vaccination,” the investigators wrote. “For example, aHRs 13–24 weeks after first vaccine doses were 0.94 (95%CI 0.90–0.98) after ChAdOx1 and 0.85 (0.81–0.88) after BNT-162b2. Corresponding aHRs after second doses were 0.68 (0.63–0.73) and 0.77 (0.72–0.83) respectively. aHRs for mRNA booster vaccination after primary course of ChAdOx1 were 0.63 (0.54–0.74) 13–24 weeks after BNT-162b2 and 0.55 (0.47–0.65) 5–24 weeks after mRNA-1273. After a primary course of BNT-162b2, aHRs for booster vaccination were 0.56 (0.49–0.63) 13–24 weeks after BNT-162b2 and 0.58 (0.45–0.74) 5–24 weeks after mRNA-1273.”2
What You Need to Know
The study found that heart attacks and strokes were up to 10% lower 13 to 24 weeks after the first dose of a COVID-19 vaccine. After the second dose, incidence rates were up to 27% lower with the AstraZeneca vaccine and up to 20% lower with the Pfizer/BioNTech vaccine.
The research analyzed health records from 46 million adults in England between December 2020 and January 2022, almost the entire adult population of England.
While the study confirmed the overall cardiovascular safety of the vaccines, it did acknowledge some risks.
Vaccine Safety
One of the ongoing questions has been the question of vaccine safety. The investigators pointed out the incidence of myocarditis and pericarditis have been reported following mRNA-based vaccines such as the Pfizer-Biotech vaccine, and vaccine-induced thrombotic thrombocytopenia following adenovirus-based vaccines such as the AstraZeneca vaccine.
In this study, there were similarly reported findings. For example, there was a higher incidence of thrombocytopenia after the first dose of AstraZeneca vaccine within 2 weeks of administration compared to those who did not get vaccinated.
For the Pfizer-BioNTech vaccine, the risk of myocarditis saw an increased rate after each subsequent dose within the first week of administration.
“The incidence of myocarditis was higher after first dose of BNT-162b2 vaccine, with greatest aHR 1 week after vaccination (2.05; 95% CI 1.28–3.29), higher one week after second dose of BNT-162b2 (aHR 3.14; 95% CI 2.04–4.85) and higher after some mRNA booster vaccinations,” the investigators reported.2
The investigators believe the benefits outweighed the risks in this very large study. “This England-wide study offers patients reassurance of the cardiovascular safety of first, second and booster doses of COVID-19 vaccines,” said Professor William Whiteley, associate director at the BHF Data Science Centre and professor of Neurology and Epidemiology at the University of Edinburgh. “It demonstrates that the benefits of second and booster doses, with fewer common cardiovascular events including heart attacks and strokes after vaccination, outweigh the very rare cardiovascular complications.”1
References
1. Incidence of heart attacks and strokes was lower after COVID-19 vaccination, finds study of 46 million adults. July 31, 2024. Accessed August 1, 2024.
https://bhfdatasciencecentre.org/news-and-events/study-involving-nearly-whole-adult-population-of-england-finds-incidence-of-heart-attacks-strokes-lower-after-covid-19-vaccination/
2. Ip, S., North, TL., Torabi, F. et al. Cohort study of cardiovascular safety of different COVID-19 vaccination doses among 46 million adults in England. Nat Commun 15, 6085 (2024). https://doi.org/10.1038/s41467-024-49634-x
