COVID-19 is an infectious disease caused by the SARS-CoV-2 coronavirus. In most people, symptoms are mild to moderate. A vaccine is available.

Pathogen and transmission

COVID-19 disease is caused by the SARS-CoV-2 coronavirus. This belongs to the coronavirus family of viruses, which can cause colds of varying severity in humans. Animals can also contract various coronaviruses.

Coronavirus can be transmitted between people in different ways. Usually it is transmitted through droplets and aerosols that are shed by an infected person when they cough, sneeze or speak. While droplets lead to transmission in the immediate vicinity, aerosols can be suspended in the air and cause transmission over longer distances, particularly in enclosed spaces with insufficient ventilation.

Occasionally coronavirus may be transmitted through contact with surfaces or via the hands if they have virus particle droplets on them. Another person could then be infected if they get these droplets on their hands and then touch their mouth, nose or eyes.


Infection and symptoms

COVID-19 disease can occur from two to 14 days after infection with the coronavirus. On average, people get sick three to four days after infection but they are already contagious two days before symptoms appear. In other words, they can already infect others before they even know that they are sick. So even without symptoms they may be contagious.

The most common symptoms are a cough, fatigue, fever, headache, muscle or body aches, a cold and sore throat. People may also experience a loss of taste or smell. The symptoms can vary. People are most contagious while they have symptoms.

Disease progression

A COVID-19 infection affects everyone differently. Most people have mild to moderate symptoms and recover within a few days, while some get very sick and need hospital treatment. Certain people are at particularly high risk of a severe case of COVID-19.

Who is at especially high risk?

  • People aged 65 or over: the risk of a severe case of COVID-19 increases with age. Pre-existing conditions further increase the risk.
  • People aged 16 or over with Trisomy 21 (Down's syndrome)
  • People aged 16 or over with certain forms of the following chronic diseases:

        o High blood pressure
        o Cardiovascular diseases
        o Diabetes
        o Respiratory conditions
        o Diseases and treatments that weaken the immune system
        o Cancer
        o Obesity (BMI ≥ 35)
        o Kidney failure
        o Cirrhosis of the liver

If you are at especially high risk, contact your doctor or specialist if you experience cold symptoms. This will ensure that you get rapid treatment if you have contracted coronavirus.
If you are not sure whether or not you are at especially high risk, please contact your doctor.

Post COVID-19 condition (long COVID)

Post COVID-19 condition can occur after infection with the coronavirus. The most common symptoms are fatigue and exhaustion, breathing problems, and concentration and memory problems. These symptoms may be of varying severity and may affect everyday functioning. The symptoms may have existed since the COVID-19 infection or have only occurred after recovery and may change over time.

You can find more information on the page Post COVID-19 condition.

Spread and incidence

The SARS-CoV-2 coronavirus first emerged in late 2019. It quickly spread across the globe and led to the COVID-19 pandemic. As SARS-CoV-2 was a new virus, most people's immune systems were not prepared for it.

In the first two years of the COVID-19 pandemic, more than 100 million cases were recorded in Europe alone. Even in Switzerland, nearly everyone has come into contact with the coronavirus.

Ever since the beginning of the pandemic, the coronavirus has continually mutated and new variants have appeared. There were several 'waves of the virus' during which many people were infected at the same time. The severity of the disease changed over the course of the pandemic as the virus variants in circulation and the immunity of the population evolved.


The COVID-19 vaccination is recommended for those at especially high risk in the autumn/winter. It offers protection against severe COVID-19 symptoms. You'll find more information on the Vaccination page.

Frequently Asked Questions (FAQs)

Frequently asked questions about the COVID certificate can be found on the COVID certificate page.

Further information

Protect yourself and others

How can we protect ourselves and others against coronavirus infection? Find out here.

Post COVID-19 condition

All about the post COVID-19 condition.


All about the COVID-19 vaccination.


Testing strategy and where to get tested.


Recommendations for travel abroad, conditions for entry into Switzerland.

Last modification 03.06.2024

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Division Communicable diseases
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