Underweight Individuals Exhibit Slightly Lower Vaccine Effectiveness, Further Research Needed
A recent study published in The Lancet Diabetes & Endocrinology has revealed that Covid-19 vaccines are highly effective in reducing the risk of severe disease for individuals of all body sizes. The research conducted by the University of Oxford compared the outcomes of vaccinated and unvaccinated individuals at least 14 days after receiving their second vaccine dose. While the overall findings demonstrate a significant reduction in severe disease cases across all BMI categories, there were slight variations observed among different weight groups.
The study indicated that underweight individuals experienced slightly lower vaccine effectiveness compared to those with a healthy weight. Vaccinated underweight individuals showed approximately half the likelihood of hospitalization or death compared to their unvaccinated counterparts with the same BMI. Researchers hypothesize that this may be due to underweight individuals being less likely to have been vaccinated initially or potentially reflecting a reduced immune response associated with frailty or other conditions related to low body weight. However, the study emphasizes the need for further research to explore the relationship between BMI and immune responses.
People with Healthy and High BMI Significantly Benefit from Vaccination, Reduced Hospitalization and Mortality
On the other hand, the study found that people with a healthy or high BMI who received the vaccine were around 70% less likely to be hospitalized compared to those who remained unvaccinated. Additionally, individuals in the healthy and high BMI categories were approximately two-thirds less likely to die from Covid-19 two weeks after receiving their second vaccine dose.
Lead author Dr. Carmen Piernas from the Nuffield Department of Primary Care Health Sciences at Oxford highlighted that the findings provide reassurance to individuals with obesity that Covid-19 vaccines are equally effective for them as for those with a lower BMI. Dr. Piernas emphasized that vaccination substantially reduces the risk of severe illness in obese individuals if they become infected with Covid-19. The study also emphasized the need for targeted efforts to increase vaccine uptake among individuals with a low BMI, as current uptake rates are lower compared to those with a higher BMI.
The study analyzed data from 9,171,524 patients above 18 years of age who had BMI data and had not previously been infected with SARS-CoV-2. The findings revealed that both low and high BMI groups were at significantly higher risk of severe disease following two vaccine doses compared to individuals with a healthy BMI.