Why do some people have no symptoms once infected with the novel coronavirus, while others end up on a ventilator, or even dead? For a lot of different reasons, it turns out. Underlying health conditions make a difference; COVID-19 patients with heart disease, diabetes or chronic lung disease are 6 times more likely to end up in the hospital and 12 times more likely to die than healthy people. But other factors matter, too. Here are 8 factors that make a person more likely either to get COVID-19 or to fare poorly once they have it.
Adults over age 64 account for a whopping 8 in 10 COVID-19–related deaths in the U.S. Why? Older people are more susceptible to infection, more likely to need hospitalization, and more likely to have preexisting health conditions. Older immune systems don’t work as well, either.
2. Blood Type
Having certain blood types has been linked with whether a person will get the coronavirus, maybe due to the antigens on the surfaces of blood cells, which vary by blood type.
One study found people with type A blood (including AB types) were more likely to get the coronavirus, whereas people with type O blood were less likely to be infected. Results of a second study were similar: people with type A blood were 33% more likely to test positive, and people with type O blood were less likely to test positive. Other studies found that people with type AB or type B blood were less likely to get COVID-19. Previous research with the coronavirus that causes SARS found that anti-A antibodies inhibited that virus; something similar could be going on COVID-19 and those with blood type O.
People with either type 1 or type 2 diabetes could fare worse with COVID-19. It’s unclear whether it’s the diabetes making COVID-19 worse or if it’s that diabetics often have other health conditions, like heart or kidney problems.
People with diabetes are about 3.7 times more likely to die from or have a severe case of COVID-19, maybe because diabetics are more likely to have chronic inflammation and more blood coagulation and are more susceptible to pancreatic damage from the virus. Also, people whose type 2 diabetes has gotten worse tend to have weakened immune systems. A weakened immune system can lead to a cytokine storm in people with the virus. Cytokine storms are linked to serious complications in people with COVID-19.
There’s hope for some diabetics, though: people who keep their blood sugar in good ranges are less likely to get as sick with the coronavirus.
Some people may be more vulnerable to the novel coronavirus as a result of differences in their cell receptors or immune systems compared with others. Many studies are now in progress to see exactly what genetic factors can control human responses to the virus.
5. Heart Conditions
People with heart conditions or heart disease suffer more with COVID-19 infections. Likewise, getting infected also can damage your heart. One study found that 1 in 5 patients with COVID-19 developed heart damage. The actions of the virus might make the heart work harder to pump oxygenated blood through the body. The virus also may attack the heart directly; heart tissue contains the ACE2 molecule, which the virus uses to infect cells. The heart also can be damaged in a cytokine storm, a severe immune response that sometimes happens in those with COVID-19.
Obesity is considered a major risk factor for being hospitalized once infected with the novel coronavirus, according to several recent studies. One study found that obese people under age 60 were twice as likely as nonobese people to be hospitalized and were almost twice as likely to need critical care. Another study found that obese COVID-19 patients were more than twice as likely to develop severe pneumonia.
Obesity is a risk factor for severe infection, which could be why those who are obese fare worse. Obese people also can have less lung capacity and greater levels of inflammation compared with other people.
Prolonged exposure to cigarette smoke can damage the immune system and lungs and can cause chronic inflammation, all of which could put smokers at higher risk of poor outcomes with COVID-19. Smokers may have related medical conditions, like emphysema or atherosclerosis, that make them more vulnerable to getting a virus. Smoking also may increase the number of ACE2 receptors in the lungs, which the virus uses to infect cells.
People who smoke may be at greater risk of developing pneumonia or requiring breathing support. In one study, while only 4.7% of nonsmokers with COVID-19 were put in ICU, put on a ventilator or died, 12.3% of smokers had one of those outcomes.
Race may also be a risk factor for severe COVID-19. Many studies have shown a connection between Black or Hispanic patients and poor outcomes, but it’s unclear whether that is a result of genetic differences or because certain groups, like Black Americans, are more likely to be obese.
Disclaimer: This article does not provide medical advice. Do not take action based solely on this article and always consult with an appropriate healthcare professional. This article is purely for informational purposes.