Sick despite warmth and sunshine

What is a summer flu?

Summer flu occurs mainly in the warm months and has symptoms similar to a common cold. However, the term “summer flu" is misleading, as this condition has nothing to do with classical influenza.

Physicians distinguish between the ordinary cold, which can also occur in summer, and true summer flu, which is caused by enteroviruses. Especially in the summer months and early autumn, this type of infection often leads to days off from work or school. 

How does summer flu present?

Summer flu presents with a variety of symptoms that often resemble those of a conventional cold but occur at an unusual time of year. Affected people frequently complain of headache, body and throat pain and an annoying cough, which can be dry or persistent. There is also runny nose and nasal congestion, accompanied by fatigue and a general sense of malaise. In some cases mild to moderate fever can occur, but it is not always present.

In addition to typical cold symptoms, digestive problems such as nausea, abdominal pain and diarrhoea may occur, since some pathogens also affect the gastrointestinal tract. Especially in children, conjunctivitis or skin rashes such as hand-foot-and-mouth disease with blisters on hands, feet and in the mouth can appear.

Although summer flu is generally mild, symptoms can worsen if neglected. After about three days of the acute phase, symptoms usually subside and the entire infection typically lasts about a week. In rare cases, however, the virus can affect the heart muscle, so exhaustion may occur even after the main symptoms have subsided. In such a case, a doctor should be consulted urgently.

What causes summer flu?

Summer flu is caused by enteroviruses such as Coxsackie and Echo viruses, which multiply in the gastrointestinal tract and are excreted in the stool. Infection occurs mainly through contact transmission, via direct contact such as handshakes or via contaminated surfaces like door handles and taps. Contact with water that has come into contact with the pathogens also poses a transmission risk. A less common but possible route of transmission is droplet infection, for example when infected people cough or sneeze.

The immune system plays an important role in the development of summer flu. Factors such as stress, extreme temperature fluctuations and insufficient fluid intake can weaken the defences and increase susceptibility to infection. Stress, which often occurs on holiday, reduces immune defence through increased cortisol release. Air conditioning and drafts that expose the body to sudden temperature changes can also strain the immune system and promote the onset of summer flu.

Other risk factors include the rapid adaptation of the organism to extreme temperature differences, e.g. when moving from hot weather into air-conditioned rooms, and the drying out of mucous membranes due to insufficient fluid intake. This weakens their protective function and allows viruses to enter the body more easily.

How long is summer flu contagious?

Summer flu is contagious even before the first symptoms appear, because the viruses can be transmitted several days before the onset of illness. Transmission is possible two to three days before symptoms appear and during the entire duration of the illness, which is about 1.5 weeks.

During this time it is particularly important to avoid contact with other people to prevent further spread of the virus. Even if symptoms subside after about a week, the risk of contagion may remain. If the condition worsens or high fever occurs, it is advisable to see a doctor to rule out possible complications.

What is the difference between a cold and the flu?

Both flu and the common cold are viral respiratory illnesses, but they differ in important respects. The most noticeable difference is the onset of illness: while a cold develops gradually, flu symptoms begin suddenly and severely. Flu symptoms such as fever, headache and muscle aches are much more intense and set in almost immediately, whereas these complaints are usually less pronounced with a cold and often appear later in the course of the illness.

Another distinguishing feature is body temperature. High fever above 39 °C is typical for the flu and can persist for several days. With a cold, fever is usually mild or absent. In addition, the cough with flu is often dry and more painful, while the cough with a cold tends to start gradually as an irritating cough that may later become productive.

Post-flu fatigue is significantly more pronounced and may persist even after the main symptoms have subsided. With a cold, people generally feel only mildly run down. Nausea, vomiting and diarrhoea are also common accompaniments of the flu but occur less frequently with a cold.

Flu is caused by influenza viruses, while colds can be caused by various viruses including rhinoviruses, adenoviruses and coronaviruses. Flu occurs mainly in the cold months, while colds can occur year-round.

How can you prevent summer flu?

To prevent summer flu, you should take various measures that strengthen your immune system and prevent the spread of viruses. An important step is the observance of basic hygiene rules such as regular hand washing, especially after contact with public surfaces. Also avoid close contact with people who have colds to reduce the risk of infection.

Another important aspect is a healthy lifestyle. Make sure you get enough exercise, a balanced diet rich in fruit and vegetables and sufficient sleep. These factors help your immune system function optimally and better defend against cold viruses. Also drink enough fluids to hydrate your body and keep your airways moist. This makes it harder for pathogens to enter.

Avoid large temperature differences between air-conditioned rooms and the warm outdoor temperature, as these stress the body and make it more susceptible to colds. Keep the room as cool as reasonable and wear a light jacket if necessary. Especially in the summer months, it can also help to avoid direct sun exposure, as too much sun can weaken the immune system.

Home remedies for summer flu: what really helps?

• Drink plenty of water, herbal teas or diluted fruit juices. These drinks keep the mucous membranes moist and help the body fight viruses.
• Take hot lemon juice with ginger: this combination provides vitamin C, boosts the immune system and helps regenerate mucous membranes. Ginger also has antibacterial properties.
• Use various teas to relieve symptoms. For sore throat and cough, chamomile tea helps because chamomile is anti-inflammatory. For dry cough, plantain tea soothes the cough reflex. Thyme tea supports the treatment of cough and cold with its antibacterial and mucolytic properties. Rosehip tea is particularly effective for productive cough because it soothes the mucous membranes and loosens phlegm.
• Gargle with chamomile or sage tea. These teas have anti-inflammatory and soothing properties that can reduce sore throat and cough irritation.
• A saline solution made from a teaspoon of salt and a litre of water helps to clean the nasal passages and remove pathogens. You can also use ready-made nasal rinses.
• Fill a bowl with hot water and inhale the rising steam to clear a blocked nose and airways. You can also add chamomile or eucalyptus oil.
• A nebuliser or inhaler can enhance the effect of steam inhalation when treating respiratory infections and clear the airways even more effectively. This can help fight bacteria and causes of colds without immediately using active medicines.
• Use the power of Icelandic moss. This remedy is soothing and helps with dry cough. It is found in many cough lozenges and syrups.
• For fever above 39 degrees Celsius, a cold compress on the calves can help lower the temperature. Soak a cotton or linen cloth in room-temperature liquid, wrap it around the calves and cover with a dry cloth. Leave the compress on for 15 to 20 minutes.
• Use warm compresses to loosen mucus. Wrap a moist, warm cloth around the chest and cover it with a dry cloth and a blanket. Make sure the cloth is not too hot and does not constrict. Alternatively, you can use a potato compress, where the warmth is retained longer by the mashed potatoes.
• Use the healing power of chicken soup. Hot chicken soup contains cysteine, zinc and iron, which strengthen the immune system and support the healing process.
• Ventilate regularly to ensure fresh air. Damp cloths or bowls of water can help regulate humidity and protect the airways from drying out.
• Your body needs rest to fight summer flu. Take it easy with regular breaks and allow yourself at least a week of rest.

Even though summer flu is usually harmless, it can be prevented with simple behavioural rules and by strengthening the immune system. That way you stay healthy and fit even in the hot season.