It also said the absolute number of deaths was small.
“According to the statistical model, 11 out of the 15 cardiac deaths in young women that occurred within 12 weeks of a first dose of a non-mRNA vaccine were likely to be linked to the vaccine; this corresponds to 6 cardiac-related deaths per 100,000 females vaccinated with at least a first dose of a non-mRNA vaccine,” the ONS said.
Members of the public have the AstraZeneca COVID-19 vaccination at Fazl Mosque in Southfields as they host a drop in clinic, in London, on June 8, 2021. (Dan Kitwood/Getty Images)
The study also examined the effect of COVID-19 on young people, concluding that a positive test was associated with increased cardiac and all-cause mortality and that the risk was higher in those who were unvaccinated at the time of testing than in those who were vaccinated.
Noting the limitations of the method, the study said some deaths that occurred during the period may not have been registered by the cut-off date because deaths of young people and deaths that occurred soon after COVID-19 vaccination are more likely to be referred to the coroner and “registration delays can be substantial.”
Although the subgroup of deaths that occurred in hospitals were not subject to registration delays, sudden cardiac deaths mostly occur outside of hospitals and may not be captured in the data, the paper said.
Spike Protein May Be the Problem
Adam Finn, professor of paediatrics at the University of Bristol and a member of the UK’s Joint Committee on Vaccination and Immunisation, said the data generated “as many questions as answers.”
“The findings are somewhat unexpected, as concerns about rare cardiac side-effects—specifically myocarditis and pericarditis—have hitherto been particularly associated with mRNA vaccine second doses in males especially when the dose interval was short, whereas the signal reported here is primarily in non-mRNA first doses in females,” Finn said in a statement.
He said the overall data seems “reassuring,” and the increased mortality associated with a positive COVID-19 test result “raises the question whether the spike protein—which is expressed both during infection and following vaccination—is the cause.”
“The next and most pressing issue that needs to be addressed is to gather more detailed information on what the nature of the reported cardiac events actually was, as this would help us begin to understand what is really being seen in these figures and might help guide future policy and vaccine design,” he added.
