Influenza occurs seasonally, during fall and winter, in the United States and other places with temperate climates. It is possible to catch the flu in the summer, but flu-like symptoms at this time of year more likely have a different cause.
The flu is a common respiratory infection, affecting 5–20% of people in the U.S. each year.
This article explores factors that increase the likelihood of catching the flu in the summer, as well as flu symptoms, treatment options, and strategies for prevention. It also looks into other common illnesses that can cause flu-like symptoms.
The flu is a contagious respiratory infection caused by influenza viruses. In the U.S., these viruses are more active during fall and winter months, with influenza activity picking up around October and peaking between December and February.
The seasonality of influenza activity in temperate zones seems to suggest that influenza viruses prefer colder environments. Nonetheless, the viruses continue to circulate throughout the year in the U.S.
Influenza can cause mild to severe symptoms, such as:
In places with tropical climates, influenza activity remains relatively constant throughout the year.
In the Southern Hemisphere, influenza activity peaks between April and September.
It is important to note that travel can play a role. For example, a person in the U.S. may be more likely to develop the flu in the summer if they contracted the infection on a recent trip to a country in the Southern Hemisphere.
Mild to moderate influenza infections do not usually require treatment. With enough bed rest, most people who are otherwise healthy recover within a few days or weeks.
However, various treatments can help ease flu symptoms.
Antiviral medications, such as oseltamivir (Tamiflu) and zanamivir (Relenza) can help treat influenza infections.
As the National Institute of Allergy and Infectious Diseases note, antiviral drugs are most effective when a person takes them within 48 hours of developing flu symptoms.
The following home care techniques may also help alleviate flu symptoms:
- taking over-the-counter medications that reduce pain and a fever
- drinking plenty of clear fluids to stay hydrated
- drinking warm liquids, such as teas and broths, to soothe a sore throat
- taking over-the-counter cough suppressants and decongestants
- using a humidifier to add moisture to indoor air, making it easier to breathe
- inhaling steam to help open the sinuses and throat
- avoiding spicy, fatty, and oily foods that may upset the stomach
It is possible to catch the flu in the summer, but flu-like symptoms often result from other infectious illnesses, such as:
The common cold
The common cold is also a respiratory infection, but it is caused by different viruses.
While a cold and the flu cause some similar symptoms, cold symptoms are milder and rarely require medical treatment.
The most common symptoms of a cold are:
- a blocked or stuffy nose
- a sore throat
A person with a cold may also experience:
- a cough
- chest discomfort
- body aches
Unlike the flu, a cold rarely causes a headache, fever, or chills.
Bronchitis refers to inflammation of the linings of the bronchial tubes in the lungs. These tubes allow air to pass in and out of the lungs as the person breathes.
Bronchitis can follow a viral respiratory infection, such as a cold or the flu, and it can also result from a bacterial lung infection.
The most common symptom of bronchitis is a persistent cough with thick mucus. Other symptoms include:
Bronchitis can be acute or chronic. People with acute bronchitis usually recover without medical treatment, typically within a few days or weeks.
Chronic bronchitis is more serious, and it develops slowly over time. When the condition is chronic, a person experiences recurrent coughing episodes that can last for several months and occur at least 2 years in a row.
Strep throat is a bacterial infection of the throat and tonsils.
The bacteria responsible ordinarily live on the skin and in the nose and throat without causing problems. Strep throat occurs when there is an overgrowth of these bacteria in the throat.
Common symptoms of strep throat include:
- small red dots on the roof of the mouth
- pain when swallowing
- red, swollen tonsils
- white bumps or patches on the tonsils
- swollen lymph nodes in the neck
- a fever
Mono symptoms typically appear 4–6 weeks after the initial infection, and they can last for several months.
- a sore throat
- a headache
- swollen lymph nodes in the neck and armpits
- body and muscle aches
- a fever
COVID-19 can occur in people who have contracted the novel coronavirus, also known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
People with COVID-19 can experience a wide range of symptoms, which often include a dry cough and shortness of breath.
The condition may also cause at least two of the following:
- a fever
- chills, sometimes with shaking
- muscle pain
- a headache
- a sore throat
- a new loss of smell or taste
People should see a doctor if they experience persistent or worsening flu-like symptoms that last longer than 1 week.
In general, it is a good idea to receive medical care for:
- a persistent or worsening fever
- a cough that produces green or brown mucus
- difficulty breathing or shortness of breath
- chest pain when breathing
- dizziness or lightheadedness
Certain people are more likely to develop severe flu symptoms and complications. Anyone in one of the high-risk groups below should receive immediate medical attention for flu-like symptoms:
The following steps can help people protect themselves and others from contracting the flu:
- getting a flu vaccine just before or during peak flu season
- avoiding close physical contact with people who are sick
- staying home when sick
- covering the mouth and nose when coughing or sneezing
- frequently washing the hands with soap and warm water
- using alcohol-based hand sanitizer when water and soap are not available
- regularly disinfecting frequently touched surfaces, such as personal electronics, doorknobs, and keys
The following may also help boost resilience to influenza infections:
- managing stress
- getting plenty of sleep
- staying physically active
- eating a healthful, balanced diet
- drinking plenty of fluids
The flu is a contagious respiratory illness caused by the influenza virus.
In the U.S., influenza activity peaks between December and February. However, a person can get the flu in the summer.
This may be especially likely if they have recently traveled to an area, such as a country in the Southern Hemisphere, that is currently experiencing its peak flu season.
Most otherwise healthy people recover from the flu within a few days or weeks of the symptoms appearing. Resting, drinking plenty of fluids, and taking over-the-counter medications can help alleviate the symptoms.
However, some people have an increased risk of severe flu symptoms and complications. High-risk groups include adults over 65, anyone with a chronic health problem, and children under 5, especially babies. In these cases, prompt medical attention for flu-like symptoms is key.