Recent Nature communication study assesses the impact of various doses of coronavirus disease 2019 (COVID-19) vaccine on cardiovascular safety in tens of millions of adults in England.

Test: A cohort study of cardiovascular safety of various doses of COVID-19 vaccine amongst 46 million adults in England. Image Source: pedro7merino / Shutterstock.com

Understanding COVID-19 Vaccine Safety

The COVID-19 pandemic was attributable to the rapid transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Thus far, SARS-CoV-2 has infected greater than 700 million people worldwide and caused greater than seven million deaths.

Unprecedented and coordinated efforts by governments and the scientific community have led to the event of several vaccines which might be estimated to have prevented around 14.4 million deaths worldwide in the primary yr of the pandemic. By autumn 2023, around 90% of the population of England aged 12 and over had received at the least one dose of a COVID-19 vaccine.

Studies have shown that a minority of vaccinated people experience rare cardiovascular complications after COVID-19 vaccines. For instance, adenovirus-based brands similar to ChAdOx1 have been linked to vaccine-induced thrombotic thrombocytopenia, while messenger ribonucleic acid (mRNA)-based vaccines, including Moderna mRNA1273 and Pfizer-BioNTech BNT-162b2, have been linked to some cases of myocarditis.

Subsequently, assessing the chance of cardiovascular and thrombotic complications after subsequent doses of the COVID-19 vaccine is crucial.

In regards to the study

Researchers conducting the present study used your entire population-based longitudinal electronic health records (EHRs) of 45.7 million adults in England between December 8, 2020, and January 23, 2022. The aim was to quantitatively assess the associations between the primary, second, and booster doses of mRNA and non-mRNA COVID-19 vaccine and subsequent cardiovascular and thrombotic events.

Roughly 82% of people had previously been vaccinated with an initial dose of ChAdOx1, BNT-162b2, or mRNA1273 vaccine. Compared with the first-dose cohort, individuals within the second and booster cohorts were older, less prone to be non-white and deprived, more prone to have cancer, have a history of COVID-19, and take medications to lower lipid levels or blood pressure.

The National Health Service (NHS) England Secure Data Environment (NHSE SDE) was used to compile data on primary care, hospital admissions, COVID-19 vaccinations and testing, medication meting out and death registration. Quantitative analyses included estimating Cox regression to acquire adjusted hazard ratios (aHRs) and their corresponding 95% confidence intervals. Several aspects were adjusted to account for confounding aspects, including age, comorbidities, gender and former COVID-19 status.

Findings

During roughly 21 million person-years, 75,655 arterial and 21,230 venous thrombotic events were observed. Arterial thrombotic events included ischemic stroke and myocardial infarction, whereas venous events included intracranial venous thrombosis, pulmonary embolism, deep venous thrombosis of the lower extremities, and portal vein thrombosis.

After the primary, second, and booster doses of BNT-162b2 and ChAdOx1 vaccines, the incidence of composite arterial thrombotic events was just like or lower than in subjects who didn’t receive an appropriate vaccine dose. This reduction was stronger after the second and booster doses than after the primary dose. Across all vaccine brands and doses, the aHR profiles for ischemic stroke and myocardial infarction were just like those for composite arterial thrombosis.

The patterns of venous thrombotic events were just like those related to arterial events. The incidence was generally lower after the primary, second, and booster doses, with greater effects seen after the second dose and booster.

Across all vaccine brands and doses, the aHR profiles for pulmonary embolism and deep vein thrombosis were just like those for composite deep vein thrombosis. Nonetheless, the incidence of intracranial venous thrombosis was higher after the primary dose of ChAdOx1. The chance of intracranial venous thrombosis didn’t increase after the second dose or with some other vaccine brand.

The incidence of thrombocytopenia was increased after the primary dose of ChAdOx1 but not after the second dose. Compared, the incidence of thrombocytopenia was not increased after receiving a booster dose of mRNA1273 after primary ChAdOx1 vaccination or after the primary or second dose of BNT-162b2. A primary course of ChAdOx1 followed by a booster dose of BNT-162b2 13-24 weeks later was related to an increased risk of thrombocytopenia.

The incidence of mesenteric thrombus and hemorrhagic stroke was lower for all vaccine brands and doses. The incidence of myocarditis was higher after the primary and second doses of BNT162b2 vaccine and a few mRNA boosters. Otherwise, the incidence of myocarditis was lower or similar after vaccination than before or without vaccination.

The incidence of pericarditis was higher after the primary dose of BNT-162b2 and ChAdOx1 vaccine, the second dose of BNT-162b2 vaccine, and after the booster dose of mRNA-based vaccines.

Subgroup analyses showed that the associations between thrombotic events and vaccination were generally similar, with some exceptions. Men were related to higher aHRs than women for composite arterial and venous events after the primary and second doses of BNT-162b2 or ChAdOx1. As well as, after the primary doses of BNT-162b2 or ChAdOx1, aHRs for composite arterial events were higher in those of unknown ethnicity.

Conclusions

The study results support the cardiovascular safety of COVID-19 vaccines, because the potential risk of rare cardiovascular complications is outweighed by the reduced incidence of common cardiovascular events. Moreover, no recent associations or recent cardiovascular complications were reported. Together, these observations support broader acceptance of future COVID-19 vaccination programs.