People with cardiovascular disease and older adults should get an annual flu vaccine
In a trial of vaccination after a heart attack, one-year mortality fell from 4.9% to 2.9%. People with cardiovascular disease and older adults can get an autumn dose for RMB 50–150 in China.
What it takes
In China, one dose costs RMB 50–150, given each autumn.
What you may gain
A double-blind randomized trial after myocardial infarction enrolled 2,571 people; neither patients nor clinicians knew whether the injection was vaccine or placebo. Twelve-month all-cause mortality was 2.9% after vaccination versus 4.9% after placebo: HR 0.59, 95% CI 0.39–0.89. A placebo is an injection without the active ingredient. The HR for cardiovascular death was 0.59. A separate meta-analysis found major cardiovascular events in 3.6% of vaccine recipients versus 5.4% of controls: RR 0.66, 95% CI 0.53–0.83. Cardiovascular mortality was RR 0.74, 95% CI 0.42–1.30, which was not statistically significant.
Context & considerations
There is uncertainty. Grade A applies to people with cardiovascular disease. For otherwise healthy older adults, the Demicheli 2018 Cochrane review found seasonal influenza incidence falling from 6% to 2.4%, but rated that evidence low certainty and the mortality evidence very low certainty.
Research & references
Fröbert O et al. (2021). Influenza Vaccination After Myocardial Infarction: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial. Circulation. https://doi.org/10.1161/CIRCULATIONAHA.121.057042 ; Behrouzi B et al. (2022). Association of Influenza Vaccination With Cardiovascular Risk: A Meta-analysis. JAMA Network Open. https://doi.org/10.1001/jamanetworkopen.2022.8873 ; Demicheli V et al. (2018). Vaccines for preventing influenza in the elderly. Cochrane Database of Systematic Reviews. https://doi.org/10.1002/14651858.CD004876.pub4 (the review discussed in Notes).