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If you are at higher risk

June 04, 2021

How to reduce risk of infection and what to do if you get sick

Who is at highest risk for getting very sick from COVID-19?

The risk of serious illness from COVID-19 increases steadily with age, especially for those with underlying medical problems. According to the CDC, adults of any age with the following conditions can be more likely to get severely ill from COVID-19:

Visit our Coronavirus Resource Center for more information on coronavirus and COVID-19.

  • Cancer, cancer treatment, and history of cancer
  • Chronic kidney disease
  • Chronic lung diseases, including COPD (chronic bronchitis or emphysema), asthma (moderate to severe), damaged or scarred lung tissue, cystic fibrosis, and pulmonary hypertension
  • Dementia or other neurological conditions
  • Diabetes (type 1 or type 2)
  • Down syndrome
  • Heart conditions, such as heart failure, coronary artery diseases, or cardiomyopathies (diseases of the heart muscle that make it harder for the heart to pump blood to the rest of your body), or high blood pressure (hypertension)
  • HIV (human immunodeficiency virus) infection
  • Immunocompromised state (weakened immune system), including from inherited conditions or prolonged used of corticosteroids or other immune-weakening medicines
  • Liver disease, including alcohol-related liver disease, nonalcoholic fatty liver disease, cirrhosis, or scarring of the liver
  • Overweight and obesity (body mass index [BMI] of 25 or higher)
  • Pregnancy
  • Sickle cell disease, thalassemia, or other hemoglobin blood disorders
  • Smoking, current or former
  • Solid organ or blood stem cell transplant, including bone marrow transplant
  • Stroke or cerebrovascular disease, which affects blood flow to the brain
  • Substance use disorders such as alcohol, opioid, or cocaine use disorder

According to the CDC, hospitalizations have been six times higher and deaths 12 times higher among those with reported underlying conditions compared with those who did not have underlying health conditions.

A study published in the Journal of the American Heart Association found that among the more than 900 000 people hospitalized for COVID-19 in the US through November 2020, nearly two thirds (63.5%) were attributable to four conditions: obesity, hypertension, diabetes, and heart failure. In other words, these hospitalizations might not have occurred if these conditions had not been present. For all conditions, risk increased with age. And within any age group, COVID‐19 hospitalizations attributable to each medical condition was higher in Black compared with White adults.

Everything we know underscores the importance of maintaining health-promoting behaviors, even as restrictions begin to ease, especially if you have an underlying medical condition. To reduce your risk of getting sick, get vaccinated as soon as you are eligible, wear a mask, maintain a physical distance of at least six feet when you're around other people, and wash your hands often.

Everything we are learning underscores the importance of maintaining health-promoting behaviors, even as restrictions begin to ease, especially if you have an underlying medical condition. To reduce your risk of getting sick, get vaccinated as soon as you are eligible, follow CDC guidance for mask wearing and other preventive measures, and wash your hands often.

I'm older and have a chronic medical condition, which puts me at higher risk for getting seriously ill, or even dying from COVID-19. What can I do to reduce my risk of exposure to the virus?

The risk of serious illness or death from COVID-19 increases steadily with age. This is true whether or not you also have an underlying medical condition, although the sickest individuals and most of the deaths have been among people who were both older and had chronic medical conditions, such as heart disease or diabetes.

The CDC suggests the following measures for those who are at higher risk:

  • Get vaccinated as soon as you are eligible.
  • Keep at least six feet of space between yourself and others outside of your household.
  • When you go out, wear a mask, keep away from others who are sick, limit close contact, and wash your hands often.
  • Avoid crowds.
  • Avoid nonessential travel.
  • During a COVID-19 outbreak in your community, stay home as much as possible to further reduce your risk of being exposed.
  • Obtain several weeks of medications and supplies in case you need to stay home for prolonged periods of time.

Have the COVID vaccines effectively protected older adults in the real world?

A small study conducted by the CDC and published in MMWR reports that the two mRNA vaccines (Pfizer/BioNTech and Moderna) have been as effective in older adults in the real world as they were in the clinical trials that led to authorization of their use.

The MMWR study was based on 417 patients, ages 65 years and older, who were admitted to a hospital for COVID-like symptoms between early January and late March 2021. All study participants were tested for COVID-19 and asked about their COVID vaccination history.

Researchers compared those who tested positive for COVID-19 and those who had another illness, and also looked at each of the participants COVID vaccination history. Based on their comparisons and calculations, the researchers found that fully vaccinated people reduce their risk of COVID-related hospitalization by 94%. (Study participants were considered fully vaccinated two weeks after their second dose.) In clinical trials, the vaccines were 95% (Pfizer/BioNTech) and 94.1% (Moderna) effective. Effectiveness dropped to 64% in those who were partially vaccinated (defined as more than 14 days after the first dose, but less than two weeks after the second dose.)

Importantly, the vaccines did not protect against COVID-related hospitalization during the first two weeks after the first vaccine dose.

I have a chronic medical condition that puts me at increased risk for severe illness from COVID-19, even though I'm only in my 30s. What can I do to reduce my risk?

You can take steps to lower your risk of getting infected in the first place:

  • Get vaccinated once you are eligible.
  • Wear a mask indoors when you are with friends and family from outside of your household.
  • Limit contact with people outside your family.
  • Maintain enough distance (six feet or more) between yourself and anyone outside your family.
  • Wash your hands often with soap and warm water for 20 to 30 seconds.
  • Stay away from people who are sick.
  • During a COVID-19 outbreak in your community, stay home as much as possible to further reduce your risk of being exposed.
  • Avoid nonessential travel.

In addition, do your best to keep your condition well-controlled. That means following your doctor's recommendations including taking medications as directed. If possible, get a 90-day supply of your prescription medications and request that they be mailed to you so you don't have to go to the pharmacy to pick them up.

Call your doctor for additional advice specific to your condition.

How does obesity increase risk of COVID-19?

According to a review and meta-analysis that looked at 75 international studies on the subject, obesity is a significant risk factor for illness and death due to COVID-19.

When looking at people with COVID-19, the analysis found that, compared with people who were normal weight or overweight, people who were obese were

  • more than twice as likely to be hospitalized
  • if hospitalized, nearly 75% more likely to be admitted to the intensive care unit (ICU)
  • almost 50% more likely to die of COVID-19.

Obesity may impact COVID risk in several ways. For example, obesity increases the risk of impaired immune function and chronic inflammation, both of which could make it harder for the body to fight the COVID-19 infection. Excess fat can also make it harder for a person to take a deep breath, an important consideration for an illness that impairs lung function.

People who are obese are also more likely to have diabetes and high blood pressure, which are themselves risk factors for severe COVID-19. And obesity is more common in Black, Latinx, and Native Americas, who are more likely to get infected and die from COVID-19 than whites for a variety of reasons.

If you have obesity (defined as a body mass index, or BMI, of 30 or higher), stay vigilant about protecting yourself from infection. That means getting vaccinated once you are eligible, following CDC guidance for mask wearing and other prevention measures, and washing your hands often.

I have asthma. If I get COVID-19, am I more likely to become seriously ill?

The coronavirus that causes COVID-19 infection primarily attacks the upper airways and lungs. So, similar to any other respiratory infection, such as the flu or viral bronchitis, your asthma symptoms could get much worse if you get COVID-19.

However, you can take steps to lower your risk of getting infected in the first place. These include

  • getting vaccinated once you are eligible
  • physical distancing
  • wearing masks, as advised by the CDC
  • washing your hands often with soap and warm water for 20 to 30 seconds
  • staying away from people who are sick.

In addition, you should continue to take your asthma medicines as prescribed to keep your asthma under control. If you do get sick, follow your asthma action plan and call your doctor.

Do pregnant women face increased risks from COVID-19?

A large study from the CDC has found that pregnant women are at increased risk of severe COVID-19 illness compared to women who are not pregnant.

The study looked at 409,462 women, ages 15 to 44, who had symptomatic COVID-19. Of these women, 23,434 were pregnant. Even after taking age, race, ethnicity, and underlying health conditions into consideration, pregnant women were significantly more likely to need intensive care, to require a ventilator, and to require a heart-lung bypass machine, compared to women who were not pregnant. They were also 70% more likely to die.

It's important to note that the overall risk of these complications was low. For example, 1.5 symptomatic pregnant women out of 1,000 died, compared to 1.2 symptomatic women out of 1,000 who were not pregnant.

The CDC also released a smaller study, which found that women who were infected with the COVID-19 virus during pregnancy were more likely to deliver preterm (earlier than 37 weeks).

If you are pregnant, be vigilant about taking precautions. Wear a mask, physically distance from others, and avoid social gatherings. Do your best to follow the CDC's recommendations to protect yourself if someone in your household becomes infected. And talk to your doctor about the COVID-19 vaccine.

Continue to see your doctor for prenatal visits and get any other recommended vaccines. Call your doctor's office to discuss safety precautions if you have concerns.

I am pregnant and plan to eventually breastfeed my baby. Is it safe for me to get a mRNA COVID-19 vaccine?

The CDC, American College of Obstetrics and Gynecology (ACOG), and Society for Maternal-Fetal Medicine agree that the new mRNA COVID-19 vaccines (Pfizer/BioNTech and Moderna) should be offered to pregnant and breastfeeding individuals. However, the World Health Organization (WHO) recommends against use of either mRNA vaccine in pregnant women, unless the benefit to an individual outweighs the potential vaccine risks. Experts, including the WHO, believe it is most likely safe to get an mRNA COVID-19 vaccine if you're breastfeeding. As always, your own doctor is in the best position to advise you based on your personal health risks and preferences.

Here are some factors to consider. First, although the actual risk of severe COVID-19 illness and death among pregnant individuals is very low, it is higher when compared to nonpregnant individuals from the same age group. In addition, research suggests that having COVID-19 might increase risk for premature birth, particularly for those with severe illness. Transmission of the virus from mother to baby during pregnancy is possible, but it appears to be a rare event.

Early mRNA vaccine trials did not deliberately include pregnant individuals. However, subsequent trials have enrolled women who are pregnant. One such study, conducted by the CDC, published reassuring preliminary results in NEJM. The trial looked at 3958 women who received an mRNA COVID-19 vaccine between mid-December 2020 and late February 2021. All of the women were pregnant when they received the vaccine or became pregnant after getting the vaccine, and enrolled in the v-safe pregnancy registry, which tracks pregnancy and infant outcomes. Most of the women included in this analysis got the vaccine during their second or third trimester. Of these women, 827 had completed their pregnancy by the end of the study period. There were 712 live births, and the number of miscarriages and other adverse outcomes, including preterm birth and low birth weight, were similar to pregnancy outcomes reported in studies before the COVID-19 pandemic.

Another small study, which compared vaccine efficacy in pregnant and non-pregnant women, was published in the American Journal of Obstetrics and Gynecology. The study found that mRNA vaccines effectively produce antibodies that protect against SARS-CoV-2 in women who are pregnant or breastfeeding, and that this immunity is passed from mother to newborn through the placenta and breast milk.

mRNA vaccines do not contain any virus, so they cannot cause COVID-19 in a woman or her baby. And our bodies quickly break down and eliminate mRNA particles used in the vaccine, so they are unlikely to reach or cross the placenta.

I'm taking a medication that suppresses my immune system. Should I stop taking it so I have less chance of getting sick from the coronavirus?

If you contract the virus, your response to it will depend on many factors, only one of which is taking medication that suppresses your immune system. In addition, stopping the medication on your own could cause your underlying condition to get worse.

Most importantly, don't make this decision on your own. It's always best not to adjust the dose or stop taking a prescription medication without first talking to the doctor who prescribed the medication.

I heard that certain blood pressure medicines might worsen symptoms of COVID-19. Should I stop taking my medication now just in case I do get infected? Should I stop if I develop symptoms of COVID-19?

You are referring to angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), two types of medications used primarily to treat high blood pressure (hypertension) and heart disease. Doctors also prescribe these medicines for people who have protein in their urine, a common problem in people with diabetes.

Here's how this concern got started. Researchers doing animal studies on a different coronavirus (the SARS coronavirus from the early 2000s) found that certain sites on lung cells called ACE-2 receptors appeared to help the SARS virus enter the lungs and cause pneumonia. ACE inhibitor and ARB drugs raised ACE-2 receptor levels in the animals.

But observational studies in humans have found no increased risk of COVID diagnosis, hospitalization, or death in people taking ACE inhibitors or ARBs. A randomized clinical trial published in JAMA in January 2021 further bolstered the evidence for continuing these medications if you get COVID-19. The researchers enrolled adults hospitalized with mild or moderate COVID-19, all of whom were already taking an ACE inhibitor or ARB before hospitalization. About half of the participants were assigned to continue their medication and the others were assigned to discontinue it. The researchers found that people who discontinued their medications did not fare significantly better or worse than those who had continued their medications in terms of likelihood of dying, progression of COVID-19, or time to being released from the hospital.

Another consideration: abruptly stopping your ACE inhibitor or ARB could cause your blood pressure to spike or worsen any underlying heart condition, putting you at greater risk of complications from the infection.

The bottom line: at this time, the American Heart Association (AHA), the American College of Cardiology (ACC), and the Heart Failure Society of America (HFSA) strongly recommend continuing to take ACE inhibitor or ARB medications, even if you get sick with COVID-19.

Blog posts


COVID-19 and underlying conditions: Why symptoms may be more severe for people with chronic disease (recorded 5/6/20)

People who have diabetes, a heart condition, cancer, kidney disease or other underlying condition are impacted more severely if they contract the coronavirus. Harvard Medical School endocrinologist Dr. Enrique Caballero explains why. Dr. Caballero is on the staff of Brigham and Women's Hospital in Boston, Massachusetts, and is the director of diabetes education in the post-graduate medical education department at Harvard Medical School.

Entendiendo como afecta la infección por COVID-19 a personas con enfermedades crónicas subyacentes (recorded 5/6/20)

Las personas que tienen diabetes, una afección del corazón o de los riñones u otra enfermedad crónica subyacente se ven afectadas más severamente si contraen el coronavirus. El Dr. Enrique Caballero, endocrinólogo de la Escuela de Medicina de Harvard explica la forma en que estas enfermedades favorecen infecciones severas por COVID-19 y como el coronavirus puede empeorar estas condiciones crónicas.  El Dr. Caballero forma parte del personal del Hospital Brigham and Women's y es el director de educación en diabetes en el departamento de educación médica de posgrado de la Facultad de Medicina de Harvard en Boston, Massachusetts. 

COVID-19 and the vulnerable: How we can help the sick and the elderly? (recorded 3/17/20)

There's a lot we don't know about the novel coronavirus that's shutting down the world. But we do know this: The sick, the elderly, the immune-compromised are particularly at risk. If you or a loved one fall into this category, there are some things you can do to help keep COVID-19 at bay. As Harvard's Dr. Rob Shmerling points out, it starts with situational awareness.

Visit our Coronavirus Resource Center for more information on coronavirus and COVID-19.

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