Study shows higher heart risk for young women with AstraZeneca vaccine

A new analysis of immunization and death records in Britain has found that young women who received at least one dose of the AstraZeneca Covid vaccine may have been more likely to die of a heart problem in the 12 weeks after their vaccination, according to a study published in the journal Nature Communications. However, the results must be viewed with caution as the vaccine was restricted in Britain in April 2021 for young people under 30 because of the risk of rare but dangerous blood clots. By that time, the young women who were immunized would have been mainly health care workers or those who were medically vulnerable, so the results of the study may not apply to the general population. In the analysis, Covid was associated with one additional death for every 12,000 unvaccinated young people and one additional death for every 56,000 vaccinated young people. The researchers did not find a significantly elevated risk of death in any other subgroup or with the Pfizer-BioNTech mRNA vaccine. The benefits of Covid vaccines still vastly outweigh the risks, and the incidence of harmful events after vaccination remains very low, the researchers and other experts emphasized. Other studies have linked vaccine side effects to specific subgroups. Data from several countries link the mRNA Covid vaccines to an elevated risk of myocarditis and pericarditis, particularly in males between the ages of 12 and 29. Within weeks of its introduction, the AstraZeneca vaccine was linked to a rare blood-clotting disorder, particularly in young women in Britain and other countries in Europe. Although AstraZeneca’s vaccine did not clear U.S. regulatory approval, the Food and Drug Administration in December 2020 authorized a similar vaccine made by Johnson & Johnson. In April 2021, the F.D.A. called for a pause in use of the Johnson & Johnson vaccine, following reports of a blood-clotting disorder in six American women. The agency withdrew the recommended pause 10 days later, and amended the vaccine’s label to warn about the risk.