Different pathogens are behind a rather harmless cold, a real flu and a corona infection. Despite this, the symptoms are often very similar. Find out here which symptoms are typical for the respective diseases!
It is not always easy to determine whether the cause of respiratory problems is a cold , flu or an infection with SARS-CoV-2. Because the course of the disease can vary greatly from person to person and depends, among other things, on the state of health and vaccination status.
Article content at a glance:
- Symptoms at a glance
- COVID-19
- flu
- a cold
- infection
- laboratory diagnosis
- complications
- protective measures
Flu, corona or cold? Symptoms at a glance
The symptoms of flu, cold and corona infection can be very similar. For example, everyone has a cough and sore throat . But there are also a few differences. The graph below shows the frequency of symptoms of a cold, flu and the omicron variant of the coronavirus .
What are the symptoms of Corona?
The most common symptoms of Corona are cough, sore throat, fever , runny nose , headache and body aches as well as shortness of breath . Some sufferers also report disturbances in their sense of smell and taste. According to the Robert Koch Institute (RKI), gastrointestinal symptoms such as diarrhea , vomiting or nausea can also occur. Other possible symptoms include skin rashes, lymph node swelling and conjunctivitis .
With the new corona variants, however, the symptoms also seem to change slightly.
Symptoms of the novel omicron variant are:
- sore throat and difficulty swallowing
- Sniffles
- fatigue
- Sneeze
- headache and body aches
- light fever
- night sweats
- loss of appetite
However, the severity of the symptoms can vary greatly in the case of COVID-19 disease. Some people develop no symptoms, while others develop serious illnesses that can lead to lung or organ failure. People who are vaccinated have a lower risk of becoming seriously ill. A booster vaccination also acts as a booster (amplifier) for the immune system and can significantly increase vaccination protection.
Typical symptoms of the flu
There is no uniform symptom pattern for the real flu (influenza). The spectrum ranges from a few symptoms to severe disease progression. The symptoms of the flu can be very similar to those of a cold. Compared to the common cold, flu caused by influenza viruses typically starts very suddenly. Possible symptoms are:
- muscle and joint pain
- pronounced feeling of illness
- high fever (over 39 degrees Celsius)
- chills
- sweats
- exhaustion
- headache
- Sore throat
- cough
- nausea and vomiting
As a rule, the symptoms last seven to 14 days. However, a general feeling of weakness and loss of appetite can persist for a few weeks. Elderly people and patients in poorer health are at increased risk of complications.
In the case of a normal cold, there is hardly any fever
In the case of a cold (flu-like infection), typical symptoms become noticeable about two to seven days after infection. These include above all:
- Sore throat
- Runny nose (watery at first, later a stuffy nose)
- headache and body aches,
- general fatigue
- Cough
However, in contrast to the flu, those affected have little or no fever. If the symptoms of the cold subside after two to three days, this indicates an uncomplicated flu-like infection. Most of the symptoms usually disappear after about a week. Only the cough can persist for several weeks under certain circumstances.
How quickly and for how long are flu, cold and corona contagious?
In addition to the symptoms, flu, cold and corona also differ in terms of the incubation period and duration of infection:
incubation period in comparison
- Corona: After infection with the SARS-CoV-2 coronavirus, the first symptoms of the disease can become noticeable after about four to six days. The omicron variant, which is prevalent in Germany, erupts after an average of three days.
- Flu: The incubation period is about one to two days.
- Common cold: The time it takes for the disease to break out can vary between two and 14 days.
comparison of contagiousness
- Corona: If the course is moderate, the contagiousness usually decreases within ten days. In the case of severe illness or an immune deficiency, infected people can also be infectious for a much longer time.
- Flu: Sick people are contagious the day before the first symptoms appear and remain infectious for about a week. Children or people with a weakened immune system are usually contagious for longer.
- Common cold: How long people with a common cold are contagious varies greatly and depends on the pathogen. As a rule, the contagiousness decreases after about a week as the symptoms subside.
Flu, cold or corona: Clarity through laboratory diagnosis
In the case of symptoms such as fever, cough and runny nose, it makes sense to stay at home and avoid contact – including with (vaccinated) household members. A rapid antigen test can give an indication of a possible corona infection, but only a PCR test will provide clarity.
If the test is positive or if you have cold symptoms, those affected should see their doctor and follow the doctor’s instructions.
Possible complications of flu, cold and corona
Unlike the common cold, which is usually mild, the real flu and infection with the coronavirus can have serious consequences such as pneumonia . In principle, complications are possible at any age, but people with underlying diseases (e.g. cardiovascular diseases) or immunodeficiency are particularly at risk.
The dangerous thing about COVID-19 is that the disease can affect other organs (e.g. blood clotting and the nervous system) in addition to the lungs. An infection can lead to long-term health consequences (” Long Covid “). Constant exhaustion and breathing difficulties , but also metabolic diseases are among the possible consequences.
How to protect yourself from flu and corona
Flu, cold and COVID-19 are spread by viruses that are transmitted by airborne droplet infection or smear infection (e.g. touching contaminated objects). Therefore it is recommended:
- Keep your distance (at least 1.5 meters)
- frequent and thorough hand washing
- regular thorough airing (especially in shared interiors such as open-plan offices)
Vaccination also offers effective protection against flu and COVID-19 . In order to be protected against the new corona variant, the STIKO recommends a booster vaccination (3rd vaccination) in addition to the basic immunization for people aged twelve and over – preferably with an omicron-adapted bivalent mRNA vaccine. Elderly people, risk groups and healthcare workers are also advised to have a fourth vaccination.
The flu vaccination is recommended especially for risk groups. This includes, for example, people who are chronically ill, such as asthma or COPD patients as well as senior citizens. Relatives of chronically ill children should also be vaccinated before the annual flu epidemic to reduce the risk of infection.