High-Dose vs Standard Influenza Vaccine: Which Is Best for Patients With CVD?

A high-dose trivalent inactivated influenza vaccine does not significantly reduce mortality or cardiopulmonary hospitalizations in high-risk patients with cardiovascular disease when compared to standard-dose quadrivalent inactivated influenza vaccine, according to the results of a recent study.

Included in this multicenter, double-blind, randomized clinical trial were 5260 adult participants who had had recent myocardial infarction or hospitalization for heart failure, with at least 1 additional risk factor. Participants were to be vaccinated for up to 3 influenza seasons at 1 of 157 sites within the US and Canada between September 2016 and January 2019.

Of the participants, 5226 completed the trial. A total of 7154 vaccinations were administered, consisting of 2630 doses of high-dose trivalent vaccine and 2630 doses of inactivated influenza vaccine. High-dose trivalent vaccine consisted of 60 µg of hemagglutinin per strain, while the standard-dose consisted of 15 µg hemagglutinin per strain.

The primary outcomes were defined as the time to the composite of all-cause death or cardiovascular or pulmonary hospitalization during each influenza season. A secondary outcome of vaccine-related adverse events was also measured.

The researchers found that there were 975 primary outcome events in the high-dose trivalent vaccine group, consisting of 883 hospitalizations for cardiovascular or pulmonary causes, and 92 deaths from any cause. This outcome was among 884 participants during 3577 participant-seasons. In the standard-dose quadrivalent vaccine group, there were 924 primary outcome events. The outcome events for this group consisted of 846 hospitalizations for cardiovascular or pulmonary causes, and 78 deaths of any cause among 837 participants during 3577 participant-seasons.

Vaccine-related adverse reactions occurred in 1449 participants (40.5%) in the high-dose group, vs reactions in 1229 participants (34.4%) in the standard-dose group. Severe adverse reactions occurred in 55 (2.1%) and 44 (1.7%) participants, respectively.

“[T]here was no significant difference in the time to first occurrence of all-cause death or cardiopulmonary hospitalization during each enrolling season for those in the high-dose group vs the standard-dose group (hazard ratio, 1.06),” the researchers concluded.

—Leigh Precopio

Reference:

Vardeny O, Kim K, Udell JA, et al. Effect of high-dose trivalent vs standard-dose quadrivalent influenza vaccine on mortality or cardiopulmonary hospitalization in patients with high-risk cardiovascular disease. JAMA. Published online December 4, 2020. doi: 10.1001/jama.2020.23649