Summer Flu: Causes and symptoms

Summer flu is an acute viral infection of the respiratory tract. It is caused by the same virus as winter flu, which belongs to the Orthomyxoviridae family. Summer flu is less common than winter flu, but it can still affect many people, especially in environments where the virus spreads easily. It is also highly contagious.

The duration of the flu can vary depending on several factors, such as the viral strain, the infected person's overall health, and how quickly symptoms are treated. Generally speaking, the flu lasts between 7 and 10 days. Here is how the symptoms typically progress 

• Onset of symptoms: The first symptoms usually appear suddenly and include a high fever, chills and aching muscles.

• Acute phase: The most severe symptoms last for 3 to 5 days. During this period, the person may experience intense fatigue, headaches, a dry cough and a blocked nose.

• Recovery: After the acute phase, the fever and aches and pains begin to subside. The cough and fatigue may persist for a further 1 to 2 weeks.

• Return to normal: Most people make a full recovery in around 2 to 3 weeks. However, fatigue and a cough may persist for longer in some people, particularly the elderly or those with a weakened immune system.

Although the flu is more common in winter, you can still catch it in summer. Here are some possible reasons:

International travel: Air travel, particularly to or from regions where the flu is actively circulating, can increase the risk of exposure to the virus. Airports and aeroplanes are enclosed spaces where the virus can spread more easily.

Visiting crowded places: Summer events such as festivals and concerts bring large numbers of people together, thereby increasing the risk of transmission.

Air conditioning: Air-conditioned environments can help the flu virus to survive and spread. Offices, shopping centres and other air-conditioned venues can become hotspots for infection.

Viral variants: Certain flu subtypes can circulate year-round. These variants may be less susceptible to the environmental factors that limit flu spread in summer.

The symptoms of summer flu are similar to those of seasonal winter flu:

• High fever: The fever can reach 38°C to 40°C

• Chills: A feeling of intense cold despite the fever

• Headache: Localised or generalised pain in the head

• Extreme tiredness: A feeling of extreme tiredness, often debilitating

• Muscle and joint pain: Aches and generalised pain

• Sore throat: A sensation of pain or a tickling sensation in the throat

• Dry cough: Persistent, non-productive cough

• Nasal congestion or runny nose: Stuffy or runny nose

• Loss of appetite: Reduced desire to eat

• General feeling of malaise: A general sense of being unwell

These symptoms can vary in severity, and some people may experience gastrointestinal symptoms such as nausea, vomiting or diarrhoea, although these are less common.

A Word from the Doctor

“Every year, it is estimated that around 2 to 3 million serious cases of flu occur worldwide, according to the WHO. Even in summer, the flu virus can circulate, particularly via tourist travel, air conditioning and enclosed spaces. From a functional medicine perspective, we focus on the immune system, which is often weakened by oxidative stress, deficiencies in vitamin D, zinc or glutathione, and an imbalance in the respiratory microbiome. Combining rest, hydration, targeted herbal remedies (elderberry, echinacea, thyme) and micronutrition helps to reduce the severity of symptoms and support immunity as a preventative measure.”

Dr Yoni Assouly – Doctor specialising in a functional and nutritional approach

To minimise the discomfort of flu-like symptoms, here are some natural remedies to help your body recover:

1. Rest: Rest is essential to allow your body to fight off the virus. Avoid strenuous physical activity and prioritise sleep.

2. Hydration: Drink plenty of fluids to prevent dehydration. Herbal teas, broths and water are particularly recommended.

3. Honey: Honey has soothing properties for the throat and can help reduce a cough. Add a spoonful of honey to a hot herbal tea for extra comfort.

4. Herbal teas: Infusions of thyme, elderflower, or ginger can help boost the immune system and fight the virus. Thyme has antiseptic properties, elderflower is antiviral, and ginger is anti-inflammatory.

5. A balanced diet: A diet rich in vitamins (particularly vitamin C) and minerals helps to strengthen the immune system. Eat fresh fruit and vegetables, lean proteins and foods rich in antioxidants.

6. Steam baths: Steam inhalation can relieve nasal congestion and respiratory symptoms. 

7. Saltwater gargles: Gargling with saltwater can help soothe a sore throat and remove pathogens from the mouth and throat.

Flu Vaccination in France

Seasonal flu vaccination campaigns usually begin in autumn, before the flu season starts. This allows people to be vaccinated before the peak of the season, which generally occurs in winter.

Who should get a flu jab?

Vaccination is particularly recommended for people at risk of developing serious complications. Recommendations vary from country to country, but this usually includes older adults (often those aged 65 and over), people with chronic conditions, pregnant women, people with severe obesity, and those living in long-term care homes. Healthcare professionals and carers of people at risk are also often encouraged to get vaccinated.

People for whom the flu jab is not specifically recommended may still choose to have the vaccine. In many countries, it is available to anyone who wishes to protect themselves against the flu, even if they do not belong to a recommended group. Depending on the country and the health system, they may have to pay for it themselves.

Do you have to pay for the flu vaccine?

Whether the flu vaccine is free depends on the country and on your personal situation. In many places, it is free or fully covered for people in the recommended groups, which makes flu prevention easier to access. Local recommendations and costs differ, so it is best to check with your GP, pharmacist or national health authority.

When using natural remedies to ease summer flu discomfort, take these precautions. If your symptoms are severe, if they persist over time, if you have any underlying medical conditions, or if you are taking long-term medication, consult your GP for medical advice. Some natural remedies may interact with medication.

In addition to getting vaccinated, it is essential to follow a few simple steps to prevent the spread of the flu virus. Wash your hands regularly with soap and water or hand sanitiser. When you cough or sneeze, cover your mouth and nose with a tissue or your elbow to prevent the spread of infectious droplets. If you have flu-like symptoms, wear a face mask to reduce the risk of passing the virus on to others.

Stéphanie is a pharmacist (since 2010) and holds a PhD in molecular biology (since 2012). Passionate about writing, she has produced medical content for nearly 15 years. Her goal is to make information accessible and easy to understand, without ever sacrificing scientific accuracy.