Cropped image of nurse injecting Covid-19 Vaccine to a patient.

Older adults who receive flu shots have less unnecessary antibiotic use, according to new research published Oct. 28 in the Journal of Antimicrobial Chemotherapy.

The scientists used data from the Vaccine Effectiveness, Networking, and Universal Safety study database, which contained data on vaccine records from the 2015-16 through 2020-21 flu seasons. The researchers examined the link between whether or not a person got vaccinated with how often they used antibiotics, sought healthcare, were admitted to the hospital, or had a risk for death. All of the data was based on 244, 642 people over the age of 65 who visited healthcare clinics for upper respiratory infections, or URIs.

The study included 127 ,216 unvaccinated people and 117 426 vaccinated people. The mean age of people who were vaccinated was 82, compared to 77 years old in the unvaccinated group. There were 65.3% females in the vaccinated group, and 61.2% females in the group of people who didn’t get a flu vaccine. 

People who got flu shots had a low risk for frequent antibiotic use, a higher risk ratio for healthcare visits, a lower rate for hospital admission, and a lower rate for death.

“Our results suggest that the seasonal influenza vaccine might help to reduce inappropriate AMU [antimicrobial use] for URIs, although care should be taken when interpreting the results,” the study authors wrote. “This indirect benefit would be another reason to recommend seasonal influenza vaccination to the general population to enhance AMR [antimicrobial resistance] countermeasures in society.”

The authors noted that they only studied older adults, so they weren’t sure if getting flu vaccines was linked to less antibiotic use in children or younger adults. This past summer, a similar study found that the people who received flu shots had fewer prescriptions for antibiotics and needed to be on those antibiotics for less time compared to people who didn’t get influenza vaccinations.