Coronavirus: Blood group, gender, body shape – what helps you live?

As scientists race to unlock the secrets of the world’s deadliest virus, we look at some of the crucial influences that could be the difference between life and death

‘Smokers were 14 times more likely to develop severe symptoms’

The world’s best brains are starting to unpick the lethal secrets of Covid-19 to work out what makes us vulnerable and how best to defend ourselves.

OBESITY

France’s chief advisor on Coronavirus has confirmed that being overweight or obese increases your chance of dying from the infection. Professor Jean-François Delfraissy claimed this put the US, where almost a third of the population are obese, particularly in peril.

Being overweight is already being cited as the reason why the Coronavirus death rate in New Orleans – where more than 40 per cent of middleaged people are obese – is double that of New York, where 22 per cent of adults are obese.

In the UK, 58 per cent of patients who were obese and on ventilators died, compared with 44 per cent who were not overweight, according to figures from the Intensive Care National Audit and Research Centre. Diabetes expert Professor Stefan Bornstein, said this is because two common complications of obesity – Type 2 diabetes and high blood pressure – weaken the immune system.

He claims the infection can also send blood pressure soaring – which could be fatal where it’s already high. For those with diabetes, Coronavirus can also infect the pancreas and interfere with insulin production.

ETHNICITY

Early statistics indicate that black and Asian people are more than twice as likely to have severe symptoms than whites.

In the UK, 35 per cent of critically ill patients with confirmed Coronavirus are nonwhite, nearly three times the proportion in the population.

But this disparity could be caused by environmental factors, rather than race itself. Kamlesh Khunti, a professor in primary care diabetes at the University of Leicester, said: ‘For example, south Asians live in more deprived areas and have more cardiovascular disease and diabetes.’

Likewise, one in six black people live in overcrowded conditions compared with two per cent of the white British population. These poorer areas are also often plagued by another danger: air pollution, which significantly increases the risk of respiratory issues that can be fatal for Coronavirus patients. This group is also twice as likely to be affected by poverty, which is linked with lifestyle factors such as obesity.

AGE AND GENDER

The average critically ill patient is a 60-year-old male, according to latest UK data. Among Italy’s first 14,860 deaths, 68 per cent were men.

Given that men are more likely than women to have heart disease, diabetes and chronic lung disease, this is to be expected. Men are also more likely to drink, smoke and be obese in middle age, making them even more vulnerable.

One professor of immunology at Oxford University believes that genes and hormones may be the critical factor, rather than lifestyle. Philip Goulder believes that the immune system’s response is ‘typically more aggressive and effective in females compared with males’.

This may be due to the X chromosome, which carries several crucial immune-system genes. Since women have a pair of X chromosomes while men have only one (and a Y chromosome), females effectively possess double the immune genes.

BLOOD TYPES

Coronavirus infects us by attaching itself to a receptor on the outside of our cells. Its genetic material then ‘invades’ the cell and takes it over to reproduce. Some scientists theorise that, due to their genetic makeup, some people may have cells that are more resistant to invasion.

According to a yet to be published Chinese study, patients with Type-A blood had more severe Coronavirus symptoms than those with Type- O blood. The authors say it’s too early to make clinical decisions based on their findings. But there has been promising research in this area.

PREVIOUS JABS

Researchers are exploring whether the BCG vaccination against TB, given to British children until 2005, strengthens immunity against the virus.

According to US scientists, it might explain why there are fewer cases and deaths in countries such as Japan where the BCG jab has been given for decades, compared with nations such as Italy and the US that haven’t traditionally had universal vaccinations.

A study in the journal Vaccine in 2005 found that the BCG jab also reduces the severity of lower lung infections caused by viruses.

Spurred on by these findings, health workers in Australia and the Netherlands are being given the BCG vaccine in trials to see if it prevents them getting the infection, or reduce its severity if they do.

SMOKERS

Common sense says that the lasting damage smoking has on your lungs will increase your susceptibility to Coronavirus.

In fact, researchers have found that current smokers and those who have only recently stopped smoking may be at greater risk because they have higher levels of a molecule called ‘angiotensin converting enzyme II’ (ACE-2), which sits on the surface of their lung cells. This chemical acts as an ‘entry point’ that allows Coronavirus to get into the cells of the lungs.

That may explain why a survey from Wuhan, where the virus first emerged late last year, has found that smokers infected with Coronavirus were 14 times more likely to develop severe symptoms.

CATS AND DOGS

There is growing evidence – and numerous anecdotal reports from around the world – that cats can be infected with Coronavirus and spread it to other cats. So far, the biggest feline to fall victim is a fouryear-old female Malayan tiger at the Bronx Zoo in New York. Nadia, along with six other big cats, is thought to have been infected by an asymptomatic zoo keeper. The cats started showing symptoms in March.

The zoo has confirmed they ‘are otherwise doing well under veterinary care and are bright, alert, and interactive with their keepers’. But there is no direct evidence that infected felines ‘shed’ enough Coronavirus to pass it on to humans, according to Chinese researchers.

Dog owners, however, can breathe a sigh of relief, as the investigators at China’s Harbin Veterinary Research Institute claim canines are not susceptible to the infection. Farmers can also find solace in the fact that, according to more Chinese research released this week, the virus cannot thrive in pigs, chickens and ducks – though it can survive in ferrets.