The use of Pfizer and German partner BioNTech's widely used Covid-19 vaccine marginally increases the risk of heart inflammation, but the risk is higher among those infected with the coronavirus, a study published on Wednesday in the New England Journal of Medicine showed.

Among every 100,000 patients who get the vaccine, one to five will likely develop myocarditis who would not otherwise have developed it, researchers reported based on data from Clalit Health Services, a large Israeli HMO.

That rate is much higher - 11 per 100,000 - among people infected with the coronavirus...