The recombinant herpes zoster (shingles) vaccine may reduce risks of cardiovascular disease. However, existing studies have compared vaccine recipients with non-recipients and, thus, are susceptible to confounding. To mitigate these biases, we conducted a natural experiment created by the rapid transition from the live attenuated to the recombinant shingles vaccine in the United States. We compared incidences of a composite cardiovascular endpoi…