The effectiveness of COVID vaccines is significantly less in obese patients, leaving them at risk of hospitalisation and death, a study has suggested.
Obesity is associated with an increased risk of severe COVID symptoms and is known to limit the effectiveness of other vaccines.
Researchers studied the link between body mass index (BMI) and hospitalisation – and found that vaccinated people with severe obesity were 76% more likely to suffer hospitalisation or death.
More than half – 55% – of people with severe obesity had low levels of antibodies six months after their second dose, compared to 12% of people with a normal BMI.
Agatha A Van Der Klaauw, a clinical lecturer in metabolic medicine at Cambridge University, wrote in The Conversation: "We know people with obesity have an impaired immune response to other vaccines including those for influenza, rabies and hepatitis.
"COVID-19 vaccines generate antibodies which recognise the spike protein, a protein on the surface of SARS-CoV-2 (the virus that causes COVID-19) that allows it to attach to and infect our cells.
"The vaccines also prime immune cells called T cells to protect against severe COVID-19 if we do contract the virus.
"Because immunity acquired after two doses wanes in the months afterwards, many countries have elected to administer booster vaccines to maintain immune protection, particularly in vulnerable groups."
The researchers found that a third booster vaccine restored some immunity – but again declined in people with severe obesity.
They write: "As obesity is associated with increased hospitalisation and mortality from breakthrough infections, our findings have implications for vaccine prioritisation policies."
Inhaling pure oxygen could offer relief to long COVID sufferers for heart-related symptoms, research suggested this month.
That study found that hyperbaric oxygen therapy dealt with heart-related symptoms of long COVID. It also showed that around half of long COVID patients had impaired cardiac function.
Patients with post-COVID syndrome may also develop cardiac dysfunction and are at increased risk of a range of cardiovascular disorders.
Hyperbaric oxygen therapy (HBOT) involves inhalation of 100% pure oxygen at high pressure to increase delivery to the body's tissues, which is particularly beneficial for tissues that are starved of oxygen due to injury or inflammation.
Watch: COVID no longer a global health emergency, Who says