Influenza vaccines keep preventing admissions and deaths, with no new safety signal

Design

Systematic review of 69 studies (21 RCTs, 23 comparative observational)

Population

US-licensed influenza vaccine recipients across age groups, pregnancy and immunocompromise

Primary outcome

Vaccine effectiveness against hospitalisation and death; safety

Effect

Paediatric VE vs death 80% (95% CI 75–84%); high-dose relative VE 43.6% (27.5–56.3%)

This JAMA systematic review updated the evidence on US-licensed influenza vaccines with 69 studies published between August 2025 and June 2026, including 21 randomised trials.

In older adults, vaccination was associated with fewer influenza hospitalisations (vaccine effectiveness from 19% to 43% across seasons) and deaths (29% to 66%). High-dose vaccine outperformed standard dose against hospitalisation in older adults in trial data (relative effectiveness 43.6%, 95% CI 27.5–56.3%). In children aged 6 months to 17 years, effectiveness against laboratory-confirmed influenza death was 80% over eight seasons, and vaccination in pregnancy was associated with 44.4% effectiveness against symptomatic influenza in infants.

A self-controlled case series of almost 10 million vaccinees found no rise in serious adverse events, including Guillain-Barré syndrome, whether the vaccine was given alone or with RSV or COVID-19 vaccines. Most effectiveness estimates are observational, and seasonal effectiveness varies with strain match, but the direction is consistent.

• Offer influenza vaccine before the season to adults over 65, pregnant women, children and immunocompromised patients.
• Prefer high-dose or enhanced vaccine for older adults where available.
• Co-administer with RSV or COVID-19 vaccines when due; no added safety signal was found.
• Vaccinate in pregnancy — it protected infants too young to be vaccinated themselves.
• In India, align timing with local influenza peaks, which vary by region and often follow the monsoon.

Why it matters

It gives current numbers to answer vaccine hesitancy this season, including the co-administration question.

Don't overread it

Most effectiveness estimates are observational and US-based, and effectiveness varies by season and strain match.

The statistics, in plain English

Vaccine effectiveness of 80% means vaccinated children had about one-fifth the risk of influenza death of unvaccinated children. Most estimates come from observational designs such as test-negative studies, which can be biased by who chooses to be vaccinated. The wide seasonal range (19–43% against hospitalisation) reflects how well each year's vaccine matched circulating strains.

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