COVID-19 can be life-threatening, but for most people it is not. The overall infection fatality rate in 2024 was estimated at 0.048% in Austria, one of the few countries that tracked it closely, meaning roughly 1 in 2,000 infections resulted in death. That number, however, varies enormously depending on age, underlying health conditions, and vaccination status. For some groups, the risk is vanishingly small. For others, it remains serious.
How Age Shapes the Risk
Age is the single strongest predictor of whether a COVID-19 infection becomes fatal. Among children and teenagers (ages 0 to 19), the infection fatality rate in pre-Omicron studies was 0.0003%, or roughly 3 in a million. For adults in their 20s, it was about 0.002%. The rate climbs steadily from there: 0.011% in the 30s, 0.035% in the 40s, 0.123% in the 50s, and 0.506% in the 60s. For adults 85 and older, 2024 Austrian data put the fatality rate between 0.8% and 1.2%, depending on vaccination status and whether they lived in a nursing home.
That steep age gradient means most of the life-threatening risk concentrates in older adults. A healthy 25-year-old and an 80-year-old with chronic illness are facing fundamentally different diseases, even though they carry the same virus.
Pre-Existing Conditions That Raise the Risk
Certain chronic health conditions roughly double or triple the odds of dying from COVID-19, independent of age. In a large international analysis, kidney disease carried the highest risk, with 2.7 times the odds of death compared to people without the condition. Diabetes doubled the risk (2.0 times), and obesity nearly doubled it (1.9 times). Cardiovascular disease increased the odds by 1.7 times, lung disease by 1.6 times, and high blood pressure by 1.3 times.
These risks compound. A person in their 70s with diabetes and kidney disease faces a meaningfully different threat than a person the same age with no chronic conditions. This is why early pandemic mortality was so concentrated in nursing homes, where residents tend to be both elderly and managing multiple health problems simultaneously.
How COVID-19 Actually Kills
When COVID-19 turns fatal, it typically follows a recognizable progression. The virus initially infects the lungs, and in about 81% of confirmed cases the illness stays mild. Roughly 14% of cases progress to severe pneumonia, and about 5% develop acute respiratory distress syndrome, sepsis, or multi-organ failure.
The key driver of that progression is the immune system itself. In severe cases, the body launches a massive, uncontrolled release of inflammatory molecules. This flood of inflammation damages the delicate air sacs in the lungs, making it increasingly difficult to get oxygen into the blood. But the damage doesn’t stop at the lungs. That same inflammatory cascade can injure the heart muscle, reprogram the lining of blood vessels, trigger widespread clotting, and cause kidney failure. It can become a whole-body crisis rather than just a respiratory infection.
Before vaccines were available, 18% of hospitalized COVID patients died. Among those sick enough to need intensive care, the death rate was 44.2%.
How Current Variants Compare
The dominant variants circulating today are descendants of Omicron, which spreads more easily than earlier strains but causes less severe disease. That shift in severity, combined with near-universal levels of immunity from prior infections and vaccination, has substantially reduced the overall fatality rate. The 2024 overall infection fatality rate of 0.048% is a fraction of what it was during the first two years of the pandemic.
COVID-19 still kills more people per hospitalization than seasonal influenza, though the gap has narrowed. In the 2023-2024 fall and winter season, the 30-day death rate among hospitalized COVID patients was 5.7%, compared to 4.2% for hospitalized flu patients. After adjusting for patient differences, COVID carried about 1.35 times the mortality risk of influenza. That gap was larger the previous year (1.61 times), suggesting a gradual convergence.
Vaccination and Mortality
Vaccination remains one of the clearest ways to reduce the life-threatening potential of COVID-19. A large French study tracking adults aged 18 to 59 over four years found that vaccinated individuals had a 74% lower risk of dying from severe COVID compared to unvaccinated individuals. They also had a 25% lower risk of dying from any cause during the study period. In the six months immediately following vaccination, all-cause mortality dropped by 29%.
The Risk Doesn’t End With Recovery
One underappreciated dimension of COVID’s threat is what happens after the acute infection resolves. Research following hospitalized patients after discharge found that elevated mortality persisted for up to two years. The causes of these later deaths included heart failure, cancer progression, kidney disease, chronic lung disease, and dementia. People who already had these conditions before their COVID hospitalization were at particularly high risk.
This lingering vulnerability likely reflects the lasting damage that severe infection can inflict on the cardiovascular, respiratory, and immune systems. It means that for some patients, surviving hospitalization is not the end of the danger.
Emergency Warning Signs
Most COVID infections resolve at home without incident. But certain symptoms signal that the illness has become a medical emergency. The CDC lists these warning signs: trouble breathing, persistent pain or pressure in the chest, new confusion, inability to wake or stay awake, and skin, lips, or nail beds that appear pale, gray, or blue. Any of these warrants a call to 911. When calling, let the operator know the person has or may have COVID-19.