COVID-19, cold, flu: the symptoms at a glance

The symptoms of infection with the SARS-CoV-2 coronavirus are similar to those of the common cold or flu. The conditions cannot be distinguished by these symptoms alone. This section covers the typical symptoms, what people should do if they become ill and how they can protect themselves against infection.

At a glance

  • COVID-19, flu and common colds are infectious respiratory infections that are triggered by various viruses.
  • Common symptoms of all three conditions are a high temperature, sore throat, cough or rhinitis (sneezing, itchiness and a blocked or runny nose), although a high temperature is only rarely associated with a common cold.
  • Anyone with symptoms should stay at home and call a medical practice to discuss how they should proceed.
  • COVID-19 and flu can become severe, and complications can develop, which is not usually the case with common colds.
  • Respiratory infections can be prevented through physical distancing and hygiene measures as well as regular ventilation.
  • To get through the autumn/winter safely, the German Standing Committee on Vaccination (Ständige Impfkommission, STIKO) recommends both COVID-19 and flu vaccinations.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

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Differences between COVID-19, flu and common cold

COVID-19, common colds and flu are all infectious respiratory conditions caused by infection with a specific pathogen. The infections are caused by a number of different viruses. Whereas rhinoviruses can be responsible for common colds and influenza viruses for flu, for example, COVID-19 is caused by the SARS-CoV-2 coronavirus. 

As the symptoms of COVID-19 are similar to those of flu or the common cold, the conditions cannot be distinguished by the symptoms alone. Even a self/rapid test – unlike a laboratory test – cannot necessarily do this.

Important: Anyone who develops a high temperature, limb pain, cough, rhinitis (sneezing, itchiness and a blocked or runny nose) or other symptoms of a cold or flu should stay at home and contact a doctor by telephone. Any positive COVID-19 self-tests must be immediately reported to the medical personnel so that the result can be checked using a laboratory test. All contact with others – including (vaccinated) household members – should be reduced to the greatest possible extent until the laboratory results have been received.

Further information on what people should do in the event of a suspected SARS-CoV-2 infection and when quarantine and isolation are necessary can be found at infektionsschutz.de – a website from the Federal Center for Health Education (Bundeszentrale für gesundheitliche Aufklärung – BZgA).

COVID-19, flu or cold?

The video below explains the difference between flu, cold and COVID-19, and what you should do if you develop any symptoms of a cold.

This and other videos can also be found on YouTube.

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What are the symptoms of COVID-19?

For many people with COVID-19 in Germany, the symptoms are a cough, high temperature or rhinitis (sneezing, itchiness and a blocked or runny nose). Other potential symptoms are a sore throat, headaches and joint pain as well as general debility and, in the more advanced stages, dyspnea (shortness of breath). One distinct feature of COVID-19 is that people can experience changes to their sense of smell or taste.

They may also experience nausea, abdominal pain, diarrhea, conjunctivitis, a skin rash, lymphedema and light-headedness. 

There are many different forms that COVID-19 can take and they vary considerably. Infection with the SARS-CoV-2 coronavirus can be asymptomatic. However, there are also severe cases with complications such as pneumonia, which can lead to lung and organ failure or even death. 

Important: Many people can still get infected with COVID-19 and become seriously ill because they have not been previously infected or not yet been vaccinated. This can also happen to people who have been vaccinated – although to a far lesser extent. To prevent SARS-CoV-2 from spreading rapidly and overloading the healthcare system, the infection control measures continue to apply.

What are the distinctive signs of flu?

A characteristic sign of flu (influenza) is the sudden onset of the condition with a high temperature, cough and sore throat accompanied by headache and/or joint pain and in most cases severe discomfort.

Other possible symptoms include general debility, severe sweating, rhinitis (sneezing, itchiness and a blocked or runny nose) as well as in rare cases nausea, vomiting and diarrhea.

Only a third of people infected with flu have the typical form of the condition with a high temperature. Another third have a milder form and the final third do not develop any symptoms at all.

Important: Often, older people do not develop a high temperature although they are at a far higher risk of a severe case than children, who typically experience a high temperature.

Most forms of flu are mild and people recover within a week without the need for treatment. However, the cough and general feeling of weakness can persist for much longer.

The most common complications of flu involve pneumonia. Middle ear infections may also develop in children. Encephalitis or myocardial inflammation are rare.

What happens during a flu outbreak?

Almost everyone contracts flu as a child and develops a basic level of immunity at an early age. Since flu viruses mutate very rapidly though, many people become susceptible to the flu again within a few years of an infection.

During a flu outbreak approximately 5% to 20% of the population is infected.

During a flu outbreak approximately 5% to 20% of the population is infected. There can also be peaks where a particularly high number of people become infected and ill.

Particularly severe flu outbreaks where lots of people need to be treated and ventilated in intensive care units at the same time can temporarily and regionally overload the healthcare system.

Increasing numbers of infections and simultaneous outbreaks of COVID-19 and flu risk exacerbating the care situation in hospitals and intensive care units.

Important: The flu outbreak in 2020/21 “failed” globally, primarily due to the COVID-19 protective measures, which also successfully prevented flu viruses from spreading. However, this could lead to far more people being susceptible to infection with the flu viruses that are currently circulating. In particular, people with an increased health risk or a risk of infection as a result of their job should therefore get vaccinated against the flu.

Further information about the flu can be found at www.infektionsschutz.de (in German).

The GrippeWeb – an online portal from the Robert Koch Institute – also provides additional information about the flu (in German).

What are the signs of a common cold?

A common cold is often characterized by rhinitis (sneezing, itchiness and a blocked or runny nose), coughing and occasionally a sore throat. High temperatures are less common in colds than in flu. Complications do not usually occur.

Further information about the common cold can be obtained from the Lung Information Service provided by the Helmholtz Zentrum München.

How can people protect themselves against a common cold, the flu and COVID-19?

The best way to protect yourself and others from an infection with cold, flu and SARS-CoV-2 viruses is to avoid close contact with other people and follow the hands, face, space (AHA) and ventilation (+L) guidance.

People can effectively protect themselves against COVID-19 and the flu by observing the hands, face, space, ventilation (AHA+L) guidance and getting vaccinated.

A further important measure with regard to infection control is to get vaccinated against COVID-19 and the flu. Where necessary, doctors can administer these vaccinations at the same time.

Important: The COVID-19 vaccination provides effective protection against becoming seriously ill with COVID-19 but it is still possible to become infected with SARS-CoV-2. To date, experts assume that the vaccination significantly reduces the risk of infection and that people who are vaccinated are less contagious for others.

Further information about COVID-19 and vaccination can be found in the article COVID-19 vaccination: answers to the most important questions

The website www.impfen-info.de provides questions and answers on the topic of flu vaccination (in German).

Information on how to properly follow the hands, face, space, ventilation (“AHA+L”) guidance and what to bear in mind can be found at www.infektionsschutz.de (in German).

In cooperation with the Robert Koch Institute (RKI). As at:

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