At least one of the vaccines approved for use against COVID-19 could be less effective in obese people,

according to a new study.

Research shows that healthcare workers with a body mass index (BMI) of more than 30 (the standard definition for obesity) produced only about half the amount of antibodies from the Pfizer/BioNTech vaccine, when compared with non-obese people.

The findings from the study, called Obesity May Hamper SARS-CoV-2 vaccine immunogenicity, hasn't as yet been peer-reviewed, but could mean that people with obesity might need an extra booster jab in order for them to create the needed protection against the virus.

In their report, a team of researchers from the Istituti Fisioterapici Ospitalieri in Rome, Italy, wrote: "These findings imply that females, lean and young people have an increased capacity to mount immune responses when compared with males, overweight and the older population.

"Although further studies are needed, this data may have important implications for the development of vaccination strategies for COVID-19, particularly in obese people."

The findings were based on a study of 248 healthcare workers who had received their second dose of the Pfizer/BioNTech vaccine.

"The effectiveness of COVID-19 vaccines in people with obesity is a critical issue," the researchers said.

"Since obesity is a major risk factor for morbidity and mortality for patients with COVID-19, it is mandatory to plan an efficient vaccination programme in this subgroup.

"Evidence suggests that SARS-CoV-2 infections are more severe and linger for about five days longer in people who are obese than in those who are lean.

"The constant state of low-grade inflammation, present in overweight people, can weaken some immune responses, including those launched by T cells, which can directly kill infected cells."

To download and read the full report, click here.