COVID-19 can be deadly, but the risk varies enormously depending on your age, overall health, and whether you’ve been vaccinated or previously infected. For people under 50, the infection fatality rate is very low. For older adults with chronic health conditions, it remains a serious threat, though far less so than in the early pandemic years.
How Deadly COVID-19 Is by Age
Age is the single strongest predictor of whether a COVID-19 infection turns fatal. A large analysis of pre-Omicron data found the following infection fatality rates for people under 70:
- Ages 0 to 19: 0.0003% (roughly 3 in a million)
- Ages 20 to 29: 0.002%
- Ages 30 to 39: 0.011%
- Ages 40 to 49: 0.035%
- Ages 50 to 59: 0.123%
- Ages 60 to 69: 0.506%
For the entire population under 60, the median infection fatality rate was 0.034%, meaning roughly 1 in 3,000 infections resulted in death. That number climbs steeply after 70. Adults over 80, particularly those in care facilities, faced fatality rates many times higher during the early waves of the pandemic, though exact figures varied widely by country and time period.
These numbers reflect all infections, including the many mild or asymptomatic cases that never led to a hospital visit. If you only look at hospitalized patients, the death rates are significantly higher at every age.
How COVID-19 Compares to the Flu
One of the most common questions is whether COVID-19 is really worse than seasonal flu. The cumulative toll tells the story clearly: through February 2023, the United States accumulated as many COVID-19 deaths in three years as it would typically see from flu and pneumonia over 17 years. That ratio varied by state, from about 9 years in some to more than 21 in others, but the national picture was consistent. COVID-19 killed at roughly five times the annual pace of flu and pneumonia combined during its first three years.
That gap has narrowed as population immunity has grown through vaccination and prior infection. Current variants cause less severe illness on average. But COVID-19 still causes more deaths per year than influenza in most countries tracking the data.
Why Some People Die From COVID-19
The virus primarily attacks the lungs. It damages the tiny air sacs where oxygen enters your blood, causing widespread lung inflammation. In severe cases, this progresses to acute respiratory distress syndrome, where the lungs fill with fluid and can no longer deliver enough oxygen to sustain the body.
The damage isn’t limited to the lungs. The virus triggers an intense inflammatory response. In some patients, the immune system essentially overreacts, flooding the body with inflammatory molecules that damage blood vessels, the heart, and the kidneys. Fatal cases often involve a cascade of organ failures: the lungs fail first, followed by the heart and kidneys. This inflammatory process, where the immune system itself becomes destructive, is a major driver of death in hospitalized patients.
Health Conditions That Raise the Risk
Certain chronic conditions significantly increase the chance that a COVID-19 infection becomes fatal. A meta-analysis of over 423,000 patients found that obesity raised the odds of dying by about 34 to 50 percent compared to patients at a healthy weight. Diabetes increased mortality odds by roughly 17 to 52 percent, depending on the analysis method. Acute kidney injury was one of the strongest risk factors, roughly doubling the odds of death.
Other conditions consistently linked to higher mortality include heart disease, chronic lung disease, and conditions that weaken the immune system (such as cancer treatment or organ transplant medications). The more of these conditions a person has, the higher the cumulative risk. For a healthy 40-year-old, COVID-19 is extremely unlikely to be fatal. For an 80-year-old with diabetes, obesity, and kidney disease, it remains genuinely dangerous.
How Newer Variants Changed the Picture
The virus has evolved considerably since 2020, and newer variants cause less severe disease on average. A multinational study published in The Lancet found that hospitalized patients during the Delta wave (mid-2021) were about 44% more likely to die than those hospitalized during the Omicron wave. Among patients 70 and older, Delta carried 66% higher mortality risk compared to Omicron.
A U.S. comparison put this in more concrete terms: the adjusted mortality risk for hospitalized patients dropped by about 5 percentage points from the Delta period to early Omicron, and by nearly 13 percentage points from Delta to later Omicron. That’s a substantial decline. Part of this reflects the virus itself becoming less lethal to lung tissue, and part reflects rising population immunity from vaccines and prior infections working together.
How Vaccines and Treatments Reduced Deaths
Vaccination had a dramatic effect on COVID-19 mortality during the first two years of the pandemic. In the first and second quarters of 2021, vaccinated adults over 60 had only about 19 to 27% of the death risk that unvaccinated adults faced. For younger adults (15 to 59), vaccination cut mortality risk by more than half during the same period.
That protection weakened over time. By mid-2022, the gap between vaccinated and unvaccinated mortality had largely closed for people who had only received their primary vaccine series without boosters. This reflects both waning antibody levels and the shift toward Omicron variants that partially evade older vaccine-generated immunity. Updated boosters restore some of that protection, particularly for older adults and those with weakened immune systems.
Antiviral treatments also help. Among the oldest and sickest hospitalized patients, treatment with oral antivirals reduced 28-day mortality risk by roughly 1 to 2 percentage points compared to no treatment. That may sound modest, but in a population where many patients die, it translates to meaningful numbers of lives saved. These drugs work best when started early in the course of illness.
What Happens After You Survive
One important finding that emerged over time is what happens to mortality risk after the initial infection clears. A large study of U.S. veterans found that the risk of death was dramatically elevated in the first 90 days after infection, about 6 times higher than in matched comparators who hadn’t been infected. From 91 to 180 days, that excess risk dropped sharply but remained about 18% above normal.
Interestingly, people who survived past the six-month mark actually showed slightly lower mortality than their matched comparators from that point forward, through at least two years. This likely reflects a “harvesting effect,” where the most vulnerable individuals died during or shortly after infection, leaving a somewhat healthier surviving population. The practical takeaway: if you recover from COVID-19 and feel well six months later, there’s no evidence of a lingering increase in your risk of death.