How Dangerous is Coronavirus?

Coronavirus disease (COVID-19) is caused by the SARS-CoV-2 virus, first identified in December 2019 in Wuhan, China, before spreading to become a global pandemic. Since then, a huge amount has been learned about exactly how dangerous the virus is and it turns out the answer varies enormously depending on who's affected.

A wide range of severity

COVID-19 can range from completely asymptomatic, meaning someone is infected but never feels unwell, through to mild cold-like symptoms, moderate flu-like illness and in more serious cases, severe pneumonia requiring hospital treatment. Most people who catch COVID-19 experience a mild to moderate illness and recover within a couple of weeks without needing medical care.

The proportion of cases that become severe has changed over the course of the pandemic. Early variants combined with no prior immunity in the population led to higher rates of severe illness. Later, a combination of widespread vaccination, some degree of immunity from prior infection and improved treatments meant that, on average, illness became milder for most people, even as new variants continued to emerge.

Who faces the greatest risk

Certain groups remain considerably more vulnerable to severe illness:

• Adults over 60, with risk increasing further with age
• People with heart disease, chronic lung conditions or diabetes
• People with weakened immune systems, including those undergoing certain cancer treatments
• People who are significantly overweight
• Pregnant women, who face a higher risk of complications

For people in these groups, COVID-19 can still lead to serious complications, including pneumonia, blood clots, organ damage and, in the most severe cases, death.

Long-term effects

Danger from COVID-19 isn't limited to the acute illness itself. A proportion of people, including some who only had a mild initial infection, go on to develop long COVID: a set of symptoms including persistent fatigue, breathlessness, brain fog and joint pain that can last for months. Long COVID is still being studied and its long-term outlook varies considerably between individuals.

How dangerous is it compared with other illnesses?

Comparisons with seasonal flu are common and broadly, COVID-19 has tended to carry a higher risk of severe illness and death than a typical flu season, particularly in unvaccinated or previously uninfected populations. That gap has narrowed over time as population immunity has built up through vaccination and prior infection. For a closer look at how the two compare, see our article on the difference between COVID and flu.

Reducing your risk

The practical steps that reduce your risk of severe illness haven't changed much: staying up to date with vaccinations if you're eligible, practising good hand hygiene, staying home when unwell and seeking medical advice promptly if you're in a higher-risk group and start to feel unwell. If you or someone you're caring for is struggling to breathe, has persistent chest pain, or seems confused or very unwell, that warrants urgent medical attention.

The bottom line

COVID-19 remains a genuine health risk, particularly for older adults and people with underlying conditions, but for most people today it behaves much like other common respiratory illnesses. Understanding your own personal risk factors and taking sensible precautions where appropriate, is the most useful way to think about how dangerous it is to you specifically.

Warning signs that need urgent attention

While most COVID-19 cases can be managed safely at home, certain symptoms warrant urgent medical attention. These include:

• Severe difficulty breathing or shortness of breath at rest
• Persistent pain or pressure in the chest
• New confusion or difficulty staying awake
• Bluish lips or face
• Inability to keep fluids down

If you or someone you're caring for develops any of these symptoms, seek emergency medical help immediately rather than waiting to see if things improve on their own.

How risk has changed with variants

Different variants of SARS-CoV-2 have shown different characteristics. The Alpha and Delta variants, which circulated earlier in the pandemic, were associated with comparatively higher rates of severe illness. Omicron and its descendants, which became dominant later, generally caused milder illness on average, though this partly reflects higher population immunity from vaccination and prior infection rather than the variant itself necessarily being inherently weaker. Omicron variants also proved considerably more transmissible, which meant that even with milder average severity, the sheer volume of infections still placed significant pressure on healthcare systems at points.

Frequently asked questions

Is COVID-19 more dangerous than the flu?

On average, yes, particularly in unvaccinated people, though the gap has narrowed considerably as population immunity has built up. See our article on the difference between COVID and flu for a fuller comparison.

Can healthy young people still become seriously ill?

It's less common, but it does happen. Most severe cases occur in older adults or people with underlying health conditions, but a small proportion of previously healthy younger people have also experienced serious illness.

Does having had COVID-19 before reduce your risk next time?

Prior infection generally provides some protection against severe illness on reinfection, though this protection isn't complete and can vary depending on the variant involved.

Protecting vulnerable people around you

Even if you're not personally in a high-risk group, the people around you might be and small precautions can make a meaningful difference to their safety. If you're feeling unwell, avoiding close contact with older relatives, people with underlying health conditions, or anyone with a weakened immune system, is one of the simplest and most effective things you can do. Testing before visiting someone vulnerable, particularly if you have any symptoms at all, is a sensible extra precaution.

If you live with or regularly care for someone in a high-risk group, it's worth being especially mindful during periods when respiratory illnesses are circulating widely, generally the autumn and winter months. Good ventilation, regular hand washing and staying up to date with your own vaccinations, where eligible, all help reduce the chance of passing the virus on to someone who could become seriously unwell from it.

Recovery outlook by risk group

Recovery outlook from COVID-19 varies considerably depending on individual risk factors. Younger, healthy people typically recover fully within one to two weeks with no lasting effects. Older adults and people with underlying health conditions may take longer to recover, even after a relatively mild initial illness and face a higher chance of hospitalisation if symptoms worsen. People who required hospital treatment, particularly intensive care, often face a longer recovery period afterwards, sometimes including physical rehabilitation, regardless of their age going in.

Understanding your own personal risk

Because so many factors influence how dangerous COVID-19 might be for a given individual, including age, underlying health conditions, vaccination status and prior infection history, it's worth thinking about your own personal risk profile rather than relying purely on general population statistics. If you're unsure how COVID-19 risk applies to your specific situation, particularly if you have an underlying health condition, a conversation with your GP can help you understand what precautions, if any, make sense for you.

A final word

COVID-19's danger has never been evenly distributed and understanding where you personally sit on that spectrum of risk is more useful than trying to answer the question in the abstract. Staying informed through reliable sources such as the NHS remains the best way to keep that understanding current.