COVID vaccines effective for all body weights, study finds

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COVID-19 vaccine effectiveness could be hindered by obesity

Vaccinated people had significantly lower odds of severe COVID vs. unvaccinated

Studies have shown that flu, hepatitis B, tetanus and rabies vaccines can be less effective in obese adults than in the general population, and many researchers wondered if the coronavirus vaccine would be any different.

A new study out of the University of Oxford suggests the answer is yes. The population-based cohort study drew from the QResearch database and included 9,171,524 participants.

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The researchers found that, compared to unvaccinated individuals in the same BMI group, those who got their shots were significantly less likely to need COVID-related hospitalization. When comparing the BMI groups against one another, the scientists found “evidence of protection against severe COVID-19 in people with overweight or obesity who have been vaccinated, which was of a similar magnitude to that of people of healthy weight,” they wrote.

The vaccine’s effectiveness was slightly lower in people who were underweight. “These results suggest the need for targeted efforts to increase uptake in people with low BMI (<18·5 kg/m²), in whom uptake is lower and vaccine effectiveness seems to be reduced,” the researchers wrote.

“Our findings provide further evidence that COVID-19 vaccines save lives for people of all sizes,” Carmen Piernas, PhD, of the University of Oxford, said in a statement. “Our results provide reassurance to people with obesity that COVID-19 vaccines are equally as effective for them as for people with a lower BMI, and that vaccination substantially reduces their risk of severe illness if they are infected with COVID-19.”

The study was published Thursday in Lancet Diabetes & Endocrinology.

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