According to a research that was published in The Lancet Diabetes & Endocrinology, the efficacy of COVID-19 vaccines was equivalent for persons with a higher body mass index (BMI) and of a healthy weight but somewhat lower for underweight people.
At least 14 days after receiving a second dose of vaccine, Oxford University researchers examined the likelihood of developing a serious illness in vaccinated vs unvaccinated individuals.
Despite the fact that the COVID-19 vaccination greatly decreased the number of serious illness cases for everyone, independent of body size, the impact was slightly less pronounced in underweight individuals.
Comparing underweight vaccinated individuals with unvaccinated individuals of the same BMI, hospitalisation or death rates were almost half as likely.
Researchers hypothesise that it may be because those who were underweight also had the lowest vaccination rates. It could also be a sign of a weakened immune system brought on by frailty or other low body weight-related disorders. Exploring the connection between BMI and immunological responses requires more study.
On the other hand, those who had vaccinations and were in the healthy and high BMI categories had a about 70% lower hospitalisation rate than those who did not. Two weeks after receiving a second dose, those with a healthy BMI or a higher BMI had a roughly two-thirds lower mortality rate than those who had not received the vaccine.
“Our findings provide further evidence that COVID-19 vaccines save lives for people of all sizes. 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,” said lead author Dr Carmen Piernas of the Nuffield Department of Primary Care Health Sciences, at Oxford.
“These data also highlight the need for targeted efforts to increase vaccine uptake in people with a low BMI, where uptake is currently lower than for people with a higher BMI,” Piernas added.
From December 8, 2020, to November 17, 2021, the study’s team included 9,171,524 patients who were over 18 years old, had BMI information, and had never before experienced SARS-CoV-2 infection. Depending on their BMI, people were categorised.
In addition, the researchers discovered that those with low and high BMI had a noticeably greater chance of developing serious illness after receiving two doses of the vaccine than those with a healthy BMI.
In comparison to a healthy BMI of 23, a BMI of 17 was associated with a 50% increase in the chance of hospitalisation, and a very high BMI of 44 was associated with a threefold increase in the risk of hospitalisation.
Although there is no known reason for the elevated risk among obese individuals, it is consistent with the greater occurrence of seasonal flu infections among those with a higher BMI. The group suggested that one possible cause might be an altered immunological response in those who are obese.
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