COVID-19 (coronavirus disease)

At a glance

  • COVID-19 is caused by a virus called SARS-CoV-2.
  • The infection leads to symptoms such as a cough, a runny and stuffy nose, and fever.
  • It is sometimes severe, especially in older people and those who already have certain other medical conditions.
  • Vaccinations are very good at preventing severe illness.


Photo of two elderly women sitting in the park

When the SARS-CoV-2 coronavirus began to spread in early 2020, a global pandemic broke out. This causes the COVID-19 disease. Most people with this now have cold-like symptoms at most, with fewer people becoming very ill. The risk of severe symptoms is greater in older people and those who already have certain other medical conditions. Vaccinations and medications can protect against the effects of the disease.


The most common symptoms of COVID-19 (omicron variant) are:

  • Cough
  • Runny or stuffy nose
  • Exhaustion
  • Sore throat
  • Headache
  • Fever

Symptoms such as joint pain, shortness of breath, loss of appetite, nausea and diarrhea are also possible, but less common. Reduced sense of taste and smell are much less common with the omicron variant than they were with earlier variants of the .

Sometimes COVID-19 infections don't cause any symptoms. But people who have no symptoms can still pass the on to others.


COVID-19 is caused by a called SARS-CoV-2. The belongs to a family of viruses known as coronaviruses. These are quite common among animals, and can be passed from animals to people. Related viruses such as MERS and SARS-CoV-1 have caused waves of infections in recent years, but they were less widespread. It is not yet clear where the SARS-CoV-2 coronavirus came from.

There are also other coronaviruses that have been known for a long time and that are common in people, causing colds in particular.

The SARS-CoV-2 coronavirus is mainly spread through droplets and smaller particles called aerosols. These form when breathing, talking, singing, coughing or sneezing. If other people breathe them in and they reach the membranes lining their nose or throat, the can be passed on.

Droplets are quite big and quickly fall to the ground. But aerosols are tiny, and can float in the air for longer and spread to other rooms.

You're more likely to catch the if you're less than 1 to 2 meters away from an infected person. But in spaces with no fresh air, you can also catch it from further away. Letting in fresh air reduces the amount of aerosols in the air. The risk of is generally higher indoors. It is much lower outdoors.

The can also be passed on by touching surfaces, but this appears to happen very rarely.

Coronaviruses contain genes that are responsible for making the different parts of the . If the genes change, the proteins on the surface of the may change too. This is known as a mutation. Mutations usually don’t have any significant effects. But sometimes they make the reproduce faster, or make it harder for the immune system to detect the . As a result, certain variants (like the omicron variant) then spread faster.

Risk factors

The risk of depends on many factors. But the main factor is the number of people currently infected in the population and in your own surroundings. The higher this number, the greater the risk of coming into contact with an infected person. You're more likely to get infected if you often physically spend time with groups of people. Also, some variants of the are more infectious than others.

Coronaviruses spread more in the winter than in the summer. One reason for this is that people tend to spend more time indoors in the winter. But environmental factors like temperature, humidity and sunlight can also play a role.

Most people who become infected develop cold-like symptoms or no symptoms at all. The risk of a severe COVID-19 depends a lot on whether you have been vaccinated or have already had the . It increases with age, too. People who already have certain other medical conditions are also more likely to develop severe symptoms. These pre-existing conditions include diabetes, cardiovascular diseases, chronic obstructive pulmonary disease (COPD), obesity, cancer and a weakened . People with Down syndrome are also at greater risk of developing severe COVID-19 symptoms.


Please note: Some of the following information describes the situation in Germany specifically. We have included links to websites with German-language information that might be useful for people living in Germany.

Most people in Germany have already had one or more COVID-19 infections – either with symptoms, or without noticing it. The Federal Ministry of Health regularly publishes information about the current rates. But many infections are no longer recorded because people often don't do PCR tests anymore.


It usually takes about three days for symptoms to develop after being infected. If you're infected, you can already pass the on to others about 1 to 2 days before your own symptoms start. The risk of infecting others is greatest about 3 to 6 days after your symptoms start. After that, you're less infectious because your has started to kill the viruses, so there are less of them. But people may be infectious for longer if they develop a severe COVID-19 or have a weakened .

Some people with a coronavirus don’t develop any symptoms at all, so they don’t notice that they have the disease. Others develop cold-like symptoms that usually clear up again within a few weeks.

COVID-19 infections are now only rarely severe. In severe cases, the viruses also multiply in the lungs. Then it becomes harder to breathe, and the concentration of oxygen in the blood drops drastically. The ’s reaction can cause pneumonia. In the worst case, that may lead to respiratory (lung) failure. If there is no longer enough oxygen in the blood, artificial respiration (help with breathing) might be needed.

The can also spread to other organs like the heart, nervous system or kidneys. In some people who have a severe , there's a strong response that can cause several organs to fail. COVID-19 can also increase the risk of thrombosis and stroke.

Severe infections often develop suddenly: The symptoms may be mild over the first few days, and then suddenly get a lot worse within a few hours.

COVID-19 is almost always mild in children. They generally don’t have any symptoms, or just cold-like symptoms. Children only rarely need intensive care treatment. In the first two years of the pandemic, some children developed a condition known as PIMS (pediatric inflammatory multisystem syndrome) several weeks after a COVID-19 . In PIMS, the overreacts and causes severe inflammations in the blood vessels and various organs. The symptoms may include a continuously high fever, conjunctivitis, vomiting and a skin rash. PIMS is a serious disease, but can usually be treated well. COVID-19 hardly ever causes PIMS in Germany nowadays.

Pregnant women only rarely develop severe COVID-19. But if they do, it can increase the risk of certain childbirth complications – like a premature birth, for instance. Mothers are unlikely to pass the on to their unborn child before the birth. That's more likely to happen during and after the birth. But children of mothers with a mild COVID-19 are born just as healthy as other children are.


Most people recover from COVID-19 within a few weeks. Only few have to be treated in hospital. Some of them need intensive care, and some may die. That risk was much higher in the first two years of the pandemic than it is now.

Most people in Germany have now been vaccinated and/or have recovered from at least one COVID-19 . In most cases that means their is well prepared so they won't get seriously ill. And infections with more recent types of coronavirus (since omicron) are less likely to cause severe symptoms than earlier types of the were. Less than 1 out of 1,000 people with COVID-19 die from the disease now.

The risk of COVID-19 making you very ill still depends on whether you have any pre-existing medical conditions and your age. This risk is very low in younger people. It increases with age or if you have a weakened . But most older people have cold-like symptoms at most nowadays, too.

Severe COVID-19 can take months to recover from. It can cause lasting physical damage. Being seriously ill can be very distressing mentally, too.

Some people who have a milder also say they have long-term problems afterwards, such as tiredness, difficulty doing everyday activities, shortness of breath, a reduced sense of taste and smell, weak muscles and trouble concentrating. Anxiety and a low mood are possible too. Long-term symptoms like these are considered to be "long COVID" if they last longer than four weeks after the . If the symptoms last longer than twelve weeks, it's called "post COVID." It is not clear how many people are affected by this and why the symptoms last longer in some of them.

After an , most people have a certain amount of immunity that protects them from getting COVID-19 again and, above all, from having severe symptoms (again).


Because COVID-19 symptoms are often similar to cold and flu symptoms, it can't be diagnosed based on the symptoms alone. But you can find out whether you have it by doing an antigen test (lateral flow test), for example. These tests are done using a swab from the throat or nose. They react to coronavirus proteins. The result is available after 15 to 30 minutes. You can buy antigen tests in places like supermarkets, pharmacies and drugstores.

Antigen tests quite often fail to detect COVID-19 infections. But if somebody has the typical symptoms and a positive antigen test result, you can assume that they have the . In rare cases, the results of antigen tests are false-positive. This means your test results are positive even though you don't have COVID-19.

PCR tests are more accurate here. They also involve doing a nose or throat swab. The swab sample is tested in a laboratory to look for coronavirus genes. PCR tests can detect small amounts of the , too. But they can't detect infections that occurred in the more distant past.

The results of PCR tests usually come back within 1 or 2 days. Nowadays health insurers only cover the costs of these tests if they are carried out in a doctor's practice or a hospital.

People who think they might have COVID-19 can call their family doctor or the out-of-hours information services. In Germany, you can reach the ärztlicher Bereitschaftsdienst on 116 117. You shouldn't go to see your doctor without calling them first, though. In an emergency (if you have difficulty breathing, for example) you should call an ambulance – on 112 in Germany and many other countries, and 911 in the U.S..

Prevention and vaccination

Vaccination can offer protection against the effects of a COVID-19 . Vaccines have been approved for people aged 6 months and above. Pregnant women can also be vaccinated.

It is still possible to become infected even if you are vaccinated, and many people still have at least cold-like symptoms. The is very good at preventing severe infections. Having another dose of the vaccine (a booster) can increase the protective effect. Vaccines that have been adapted to the omicron variant are now available.

The following vaccines have been approved in Germany:

Table: List of available coronavirus vaccines
Name of vaccine Age group (according to approval) Manufacturer
Comirnaty from 6 months Biontech/Pfizer
Spikevax from 6 months Moderna Biotech
Nuvaxovid from 12 years Novavax
Vaxzevria from 18 years AstraZeneca
Jcovden from 18 years Janssen-Cilag / Johnson and Johnson
COVID-19 Vaccine Valneva 18 to 50 years Valneva Austria
VidPrevtyn Beta from 18 years Sanofi Pasteur
Bimervax from 16 years HIPRA Human Health S.L.

The main recommendations for preventing the spread of COVID-19 are now similar to those for other respiratory (airway) infections:

  • Avoiding close contact with other people or staying at home if you have symptoms.
  • Wearing a mask (a surgical mask or an FFP2 mask) or keeping your distance can sometimes help stop you from catching the or passing it on to others.
  • Coughing or sneezing into a tissue or your elbow.
  • Regularly washing your hands can help stop the spread of viruses.
  • Airing indoor rooms can reduce the concentration of aerosols.

Doing an antigen test can help you get an idea of whether you're still contagious to others.


In mild COVID-19 cases, it is usually enough to rest until the symptoms have gone away. Medications like paracetamol or ibuprofen can help to relieve fever and pain.

Various antiviral medications are available for people who are more likely to have a severe : They include nirmatrelvir/ritonavir (Paxlovid), molnupiravir (Lagevrio) and remdesivir (Veklury). Blood-thinning medications (anticoagulants) may be recommended for people who are likely to get seriously ill from COVID-19 due to older age or other medical conditions. A treatment known as monoclonal antibody therapy is generally no longer used nowadays.

The choice of medication will depend on your individual situation. Things that may play a role include any pre-existing medical conditions you have or any other medications you take. This is because different medications may interact and affect each other. It also depends on which types of coronavirus (variants) are circulating because some medications are only effective against certain variants. The medications should be taken as soon as possible after symptoms begin.

People who are more likely to develop severe symptoms are also sometimes advised to measure the oxygen saturation in their blood every day. Devices for doing that are available in pharmacies and drugstores. Family doctors should regularly check how these patients are doing. They might have to go to hospital if their symptoms get worse.

People with a severe COVID-19 are treated in hospital. They can be given other medications (such as steroids) or oxygen there. If they have serious breathing difficulties, they will be treated in intensive care. People with respiratory (lung) failure often need help with breathing – also known as artificial respiration.

Something called ECMO (extracorporeal membrane oxygenation) can be used to treat very severe respiratory failure. Here the blood is enriched with oxygen in a machine outside the body before it is pumped back into the body. ECMO treatment is very stressful for the body and usually takes many weeks.


People who are weak or have long-lasting symptoms after a COVID-19 can apply for medical rehabilitation treatment. That includes things like breathing therapy, suitable physical exercises and strength training, psychotherapy and occupational therapy. After rehabilitation, you have the option of returning to work gradually. People who have a job should contact their statutory pension fund to apply for rehabilitation. People who are no longer working should apply to their health insurance provider.

Further information

You will find further information for people living in Germany here:

Read about how to manage coronavirus symptoms on the website of the German National Association of Statutory Health Insurance Physicians’ (Kassenärztliche Bundesvereinigung),

The Federal Working Group for Self‐help (BAG Selbsthilfe) has a website for people in Germany who are affected by long COVID or post COVID.

Centre for Disease Control and prevention (CDC). COVID-19: Testing. 2021.

Deutsche Gesellschaft für Allgemeinmedizin und Familienmedizin (DEGAM). S2e-Leitlinie SARS-CoV-2 / Covid-19: Informationen und Praxishilfen für niedergelassene Hausärztinnen und Hausärzte - Living Guideline. 2022.

Deutsche Gesellschaft für Internistische Intensivmedizin und Notfallmedizin (DGIIN), Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin (DIVI), Deutsche Gesellschaft für Pneumologie und Beatmungsmedizin (DGP) et al. S3-Leitlinie Empfehlungen zur Therapie von Patienten mit COVID-19 - Living Guideline. 2022.

European Centre for Disease Prevention and Control (ECDC). COVID-19. 2023.

European Medicines Agency (EMA). Treatments and vaccines for COVID-19. 2023.

Robert Koch-Institut (RKI). Empfehlungen der Ständigen Impfkommission. 2023.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Please note that we do not provide individual advice on matters of health. You can read about where to find help and support in Germany in our information “How can I find self-help groups and information centers?

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Updated on September 12, 2023

Next planned update: 2026


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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