Since the pandemic began, more than 6 million people have died from COVID around the world. The good news is that we now have a wide range of treatments as well as highly effective vaccines which have helped reduce the number of severe COVID cases.
Still, some people are more likely to get very sick or die from COVID than others. Our research, carried out before vaccines became available, showed that obesity is one of the factors that increases a person’s risk of being hospitalised or dying from COVID. We have now followed this up with a new study looking at how body weight affects the uptake and effectiveness of COVID vaccines, and discovered that being underweight can also be a risk factor for severe disease.
Obesity is measured using the body mass index (BMI). This is calculated by dividing a person’s weight in kilograms by their height in meters, squared. A person with a BMI below 18.5 is considered underweight, in the range of 18.5–25 is considered healthy weight, above 25 is considered to be overweight, and above 30 is considered obese.
