Research

Hormonal

Obesity impairs the efficacy of influenza vaccination, resulting in a higher incidence of influenza-like illness despite vaccination, suggesting similar immune evasion may occur with other vaccines.

Obesity can reduce how well your flu shot works, making you twice as likely to get sick compared to non-obese vaccinated people. Still get vaccinated, but be aware you may need extra precautions or discuss high-dose options with your doctor.

ModerateSupportsMEDIUM confidence
Of great concern also is the fact that persons with obesity have diminished protection from influenza immunization with a study showing that adult recipients of IIV3 with obesity have two times greater incidence of influenza and/or influenza like illness despite being vaccinated.
Donna H. Ryan et al. · Obesity · 2020

Why this rating

Based on a single cited study (Neidich et al.) regarding influenza, extrapolated to other contexts.

Source

COVID 19 and the Patient with Obesity – The Editors Speak Out

Donna H. Ryan et al. · Obesity · 2020

DOI 10.1002/oby.22808

narrative_reviewCited 214×
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DOI resolved against Crossref · corpus check 2026-06-10

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