New research published in SciTechDaily has suggested that obesity is not only a significant risk factor for severe COVID-19, but is also likely to prevent a person from developing a robust immune response following vaccination with a COVID-19 vaccine.

The study was conducted by researchers at Istanbul University, and confirmed suspicions that obese people could have a weaker immune response to vaccination, given that they are known to have a reduced response to vaccines for influenza, hepatitis B, and rabies.

Researchers measured antibody levels in several cohorts which were divided according to weight and also history of previous infection with COVID-19. Trial participants had received two doses of either the Pfizer or the CoronaVac vaccine four weeks previously.

Obese people with no previous SARS-CoV-2 infection and vaccinated with the Pfizer vaccine were found to have antibody levels over three times lower than those in the normal-weight cohort. Those in the CoronaVac cohort had antibody levels 27 times lower.

However, the antibody levels of obese people with previous SARS-CoV-2 infection were not significantly different from normal weight controls, regardless of the type of vaccine they received.