COVID-19 vaccine may be less effective on the obese, who may keep spreading the virus

Experts fear COVID-19 vaccines may be less effective in overweight people, who pose a transmission risk.

The concern among scientists and public health experts is that the UK’s weight problem could undermine the effectiveness of a vaccine. Picture: AFP

Britain’s obesity crisis could prevent a vaccine from ending the pandemic, experts have warned.

Scientists are concerned that vaccines being developed to protect against COVID-19 may be less effective in fat people, leaving them more vulnerable to infection, which could, in turn, put others at risk.

If they do become infected, obese adults face a 113 per cent higher risk of being taken to hospital, a 74 per cent increased likelihood of being admitted to intensive care and a 48 per cent higher risk of death.

The UK has one of the worst obesity rates: two out of three adults are overweight or obese. Millions have piled on the pounds since March, with an average gain of 0.7 kilograms.

A woman wearing a protective face mask sits in Liverpool city centre, northwest England. The UK has one of the worst obesity rate - two out of three adults are overweight or obese. Picture: AFP

The concern among scientists and public health experts is that this weight problem could undermine the effectiveness of a vaccine.

The ability of tens of millions of fat Britons to return safely to work, care for their families and resume daily life could be limited if the coronavirus vaccine provides weak immunity.

Vaccines against flu, hepatitis B, tetanus and rabies are less effective in obese adults than in the general population. Experts fear that the COVID-19 vaccines in development will suffer the same limitation.

Melinda Beck, professor of nutrition at North Carolina University and an expert in the link between obesity and vaccines, said: “We had a study where we had 3,400 adults enrolled and everybody received the flu vaccine. You had twice the risk of developing flu despite vaccination if you were an individual with obesity. That finding makes us worry about the COVID-19 vaccine.”

Danny Altmann, professor of immunology at Imperial College London, said: “It couldn’t be more serious. In vaccines that are already in routine use, people who are more obese tend to make a less effective response to the vaccine.” He said he had been “shown quite scary data that the more overweight you are, the more you drop your immune response”.

In July, Boris Johnson set out a plan to reduce obesity levels through measures such as a ban on unhealthy snacks at shop check-outs. Restaurants will have to display the calories in dishes on menus. There will be a consultation on doing the same for alcohol.

The prime minister admitted he was “way overweight” when he was in hospital with the coronavirus in March. He has since lost a stone and become fitter by changing his diet and going on morning runs.

Britain's Prime Minister Boris Johnson during an event to launch the government's cycling intuitive to help get people fitter. The PM has previously admitted he was “way overweight” before he contracted coronavirus. Picture: AFP

Separately, it is understood that scientific advisers have raised concerns with Downing Street that many Britons think that a vaccine will guarantee immunity from COVID-19. They are worried that those who have received a vaccine may be cavalier about social distancing and other measures. Most experts agree that no vaccine will offer full immunity.

“When I look at the trials published,” Altmann said, “it’s a case of ‘so far, so good’, since virtually all seem to do what it says on the tin. That leaves the big question of whether they’re likely to be protective. If so, will this be ‘sterilising immunity’ - no chance of virus gaining entry at all - or partially protective immunity, just mitigating the consequences of infection so that people don’t become severely ill with pneumonia?

Boris Johnson looks at an immunological assay during a visit to the Jenner Institute in Oxford, England, who are leading the COVID-19 vaccine research. Picture: Getty

“From those that have so far published protection studies in animal models, the second scenario looks a more likely prospect. So, this could see us out of the pandemic, but still leave a reservoir of the virus out there, ready to re-emerge, especially if there are communities with low herd immunity. The vaccines will help enormously, but won’t offer us a Covid-free world overnight.”

Ohid Yaqub, who lectures in science policy at the University of Sussex, said: “Some people might take it, and think, ‘I’m invincible now.’ It might encourage people not to wear masks or not distance properly, or even go clubbing.”

Hans Kluge, the World Health Organisation’s director for Europe, said a vaccine would not end the pandemic. “We don’t even know if the vaccine is going to help all population groups.”

@AndrewGregory

The Times