Underutilization of Influenza Vaccination in Populations at High-Risk for Complications

Influenza vaccinations were found to be underutilized among groups who are considered to be at high risk for complications from infection.

Influenza vaccinations were found to be underutilized among groups who are considered to be at high risk for complications from infection, according to a retrospective cohort study presented during the Basic Cardiovascular Sciences Scientific Sessions virtual meeting by the American Heart Association, held virtually, July 27 to 30, 2020.

The 2014 National Inpatient Sample (NIS) database was used to identify individuals at high risk for influenza complications (n=7,056,314), as defined by the Center for Disease Control (CDC; ie, age ≥50; presence of chronic conditions; care in nursing facilities; presence of acquired immunodeficiency syndrome; Native American or Alaskan Native descent; and high body mass index).

Of the hospitalized patients at high-risk for influenza complications, 168,325 received an influenza vaccination. High-risk patients were less likely to be vaccinated during hospitalization compared with the general population (1.8% vs 15.3%, respectively).

Patients aged ≥50 years at high risk for complications who received vs did not receive vaccination had a reduced risk for complications: myocardial infarction (MI; predicted risk [PR], 0.72; P <.0001), death during hospitalization (PR, 0.27; P <.0001), transient ischemic attacks (TIA; PR, 0.53; P <.001), and cardiac arrest (PR, 0.15; P <.0001).

Vaccinated vs unvaccinated individuals at long-term care facilities had lower rates of MI (PR, 0.86; P =.003) and TIA (PR, 0.44; P <.0001). Vaccinated individuals of Native American or Alaska Native descent or those with a body mass index >30 kg/m2 had reduced instances of MI, death during hospitalization, and TIA  compared with unvaccinated individuals of the same demography (P <.0001 for all).

Vaccination did not alter the risk for MI (PR, 0.76; P =.591), death during hospitalization (PR, 0.22; P =.138), or TIA (PR, 0.77; P =.651) among patients with acquired immunodeficiency syndrome or those who were immunocompromised.

“Flu vaccination was paradoxically underutilized in the high-risk patients and when used was associated with reduced rates of MI, TIA and cardiac arrest in all high risk cohorts compared to those who did not receive vaccination,” concluded the study authors. “These results underscore the need for health care policy initiatives to optimize flu vaccination among all patients and especially among high risk groups identified by the CDC.”


Mandania R A, Ghosh A, Ma J, et al. Magnitude and impact of underutilization of flu vaccine in high-risk US cohorts on cardiovascular events. Presented at: American Heart Association: Basic Cardiovascular Sciences. 2020. Virtual meeting. July 27-30, 2020. Presentation #398.