Some people are at a higher risk for serious infection if they catch the coronavirus that causes COVID-19. They include people age 65 and older, women who are pregnant and people with certain illnesses. COVID-19 vaccines (and boosters or additional doses when appropriate) are especially recommended for people in these groups.

Why are these people more vulnerable to more serious COVID-19? Lisa Maragakis, M.D., M.P.H, Johns Hopkins senior director of infection prevention, explains.

Older Adults and COVID-19

According to the U.S. Centers for Disease Control and Prevention (CDC), as of November 2021, more than 75% of deaths in the U.S. from COVID-19 have been among people age 65 and older. And people in this age group comprise over 42% of those who end up in the hospital due to COVID-19. Here are some reasons why:

• Older adults are more likely to have long-term health problems that can put them at increased risk for severe effects from COVID-19.
• People’s immune systems tend to weaken with age, making it more difficult to fight off infections.
• Lung tissue becomes less elastic over time, so respiratory diseases like COVID-19 are particular concerns for older people.
• Inflammation in older people can be more intense, causing organ damage.

Caring for an older person during the COVID-19 pandemic? Read more.

Underlying Conditions and Risk of Severe COVID-19

Lung Disease and COVID-19

Regardless of a person’s age, some airway and lung diseases can set the stage for a more severe coronavirus infection because of scarring, inflammation or lung damage. These include:

• Chronic obstructive pulmonary disease (COPD), such as emphysema
• Pulmonary fibrosis
• Pulmonary embolism
• Pulmonary hypertension
• Interstitial lung disease
• Bronchopulmonary dysplasia
• Bronchiectasis
• Tuberculosis

Several research studies have noted a higher chance of severe COVID-19 among smokers. A study also showed that people who vape regularly were five to seven times more likely to test positive for the coronavirus than those who don’t. Both current and former smokers and e-cigarette users may have lung damage that puts them at increased risk. Learn more about COVID-19, smoking, vaping and air irritants.

If any of these conditions apply to you, it’s important to get vaccinated, work with your doctor to learn how to help protect yourself, and ensure you have adequate supplies of maintenance and emergency medications on hand.

Learn more about lung problems caused by COVID-19.

Heart Disease and COVID-19

Although COVID-19 most often affects the airway and lungs, the heart works to drive oxygen to the body’s tissues. When the lungs are overtaxed due to illness, the heart has to work harder, which creates challenges for people who are already living with conditions such as heart failure, coronary artery disease or cardiomyopathies.

The American Heart Association notes that viral illnesses similar to COVID-19 can raise the risk of a heart attack for people with a buildup of plaque in their blood vessels. Research shows that viral illness can make it more likely for a piece of the plaque lining the vessels to break off and block blood flow to the heart.

Get vaccinated and protect yourself. Learn more about heart problems caused by COVID-19.

Cancer, Cancer Treatment and COVID-19 Risk

People of any age who are currently being treated for cancer or who recently had it are vulnerable to severe COVID-19 if they catch the coronavirus. This is especially true of those with blood cancers such as leukemia.

Cancer treatment, such as chemotherapy or stem cell or bone marrow transplant, can weaken your immune system and make it easier to become infected with contagious diseases such as COVID-19.

Talk to your oncologist about when you should be vaccinated for COVID-19 and if you need to receive an additional dose if you are undergoing any of these therapies, since treatments that suppress your immune system may affect how well the vaccines protect you.

Pregnancy and COVID-19

Women who are pregnant and women who recently gave birth who contract COVID-19 are at higher risk of severe illness, complications and death. COVID-19 may also have negative effects on pregnancy, and it has been linked to higher risk of premature birth and stillbirth. Underlying medical conditions such as heart disease and lung disease can further increase the risk for the mother and the baby. Pregnancy can also trigger changes to the immune system that can make you more vulnerable to respiratory viruses.

COVID-19 vaccines are safe, effective and strongly recommended for women who are pregnant. Learn more about COVID-19 vaccination and pregnancy.

Diabetes As a Risk Factor for COVID-19

People who have diabetes are at increased risk of getting very sick from the coronavirus that causes COVID-19. Type 1 and type 2 diabetes both cause an increase in blood sugar. Poorly controlled blood sugar can make viral diseases, including COVID-19, more dangerous, possibly because higher blood sugar can create an environment where viruses are likely to thrive.

Also, diabetes increases inflammation and weakens the immune system, making it harder for people with the condition to fight off disease in general.

People with diabetes should adhere to their medication regimens and do everything possible to keep their blood sugar under control. Having an adequate supply of medications and staying in close touch with your doctor can add to your peace of mind. Also, get vaccinated for COVID-19 and take measures to protect yourself from infection.

COVID-19 and People with a Weakened Immune System (Immunocompromised)

Several diseases and medical treatments can weaken your immune system and put you at risk for coronavirus infection and more serious COVID-19. These include some inherited (genetic) conditions, untreated HIV, long-term steroid use, solid organ or blood stem cell transplants, and some forms of cancer and cancer treatment.

Talk to your doctor about your COVID-19 vaccine if you have a weakened immune system. You may benefit from an additional dose of COVID-19 vaccine to ensure you are protected as much as possible.

Read more: After an Organ Transplant: 14 Strategies for Safer Living During the COVID-19 Era

Mental Health Conditions and Risk of Severe COVID-19

Researchers have discovered a link between some mental health conditions and increased risk of COVID-19 hospitalization and death. These conditions include mood disorders such as depression and anxiety, as well as schizophrenia and related illnesses and substance use disorders.

Experts are still working to understand why and how these conditions increase the risk of severe COVID-19. In the meantime, if you have any of these issues, getting vaccinated can help lower your risk of severe COVID-19.

Neurologic Problems and COVID-19

Dementia, Alzheimer’s disease and other cognitive and developmental problems can increase the risk of having a severe case of COVID-19, especially among people living in group care settings. Get vaccinated and take measures to protect yourself from infection.

Having epilepsy does not increase your vulnerability to the coronavirus. Read more about the impact of COVID-19 and COVID-19 vaccines for people with epilepsy.

Liver and Kidney Disease and COVID-19

People with certain chronic liver and kidney conditions may be more likely to experience severe COVID-19. This includes people with hepatitis B or C, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, liver cirrhosis and chronic kidney disease. Treatments for cancers of the kidneys or liver, such as chemotherapy, can also weaken the immune system and increase your risk of infection.

If you have any of these conditions, the CDC recommends getting vaccinated and staying in touch with your doctor to discuss any new symptoms or adjustments to your medications.

Is asthma a COVID-19 risk factor?

Research on the link between COVID-19 and asthma is ongoing. Currently, there is no conclusive data supporting the idea that having asthma makes you more likely to catch the coronavirus that causes COVID-19 or that it puts you at higher risk of severe COVID-19. However, the CDC lists moderate to severe or uncontrolled asthma as an underlying condition that may increase the risk of hospitalization. It is important to get vaccinated and to take your asthma medications as directed to keep your asthma symptoms under control.

Learn more from the CDC about all underlying conditions that are associated with a higher risk of severe COVID-19.

COVID-19 prevention guidelines apply to everyone

Although severe coronavirus illness can occur in people without any known health issues, including young adults and children, those with the conditions listed above are more likely to have a serious and even deadly case of COVID-19.

To help protect those who are in these high risk categories, everyone needs to take steps to prevent spread of the coronavirus that causes COVID-19. Getting vaccinated for COVID-19, physical distancing, frequent and thorough hand-washing, and mask wearing can lower the risk for everyone, especially the most vulnerable.