Flu shots are linked to less use of antibiotics, according to a study in Antimicrobial Resistance and Infection Control. But that link isn’t quite as strong for people who receive the pneumococcal vaccine.

The review and meta-analysis looked at data from 1998 to 2021, most of it conducted in the Americas and Europe, to make the correlations. Randomized controlled trials showed a more pronounced impact from flu shots on the number of prescriptions for antibiotics as well as days a person needed to take antibiotics, the said. That correlation wasn’t as strong when they looked at how the pneumococcal vaccine affects antibiotic use. 

When reviewing different types of studies, the team noted that randomized controlled studies and observational studies both revealed that flu shots can significantly reduce antibiotic use. Observational studies weren’t as consistent, they said.

The fact that researchers found a stronger effect with the flu shot was surprising to them because people shouldn’t treat the flu with antibiotics. They were also surprised because the vaccine effectiveness of the pneumococcal vaccine is considerably higher than that for the influence vaccine. The pneumococcal vaccine addresses illnesses caused by Streptococcus pneumoniae bacteria. Pneumococcal disease refers to infections caused by the bacteria, and can include sinus infections, ear infections, pneumonia and infections in the blood. Researchers contend that people should use both vaccines.

Getting a flu shot is an important way to lower the use of antibiotics and perhaps control the issue of antimicrobial resistance, according to the researchers.

“These interventions need to be integrated into a multi-pronged strategy that takes into account all of the other factors that can reduce antibiotic use over time, such as antibiotic stewardship policies, raised awareness about rational antibiotic use through antibiotic campaigns and/or access to antimicrobials,” the researchers said.