Influenza or flu, is a prevalent respiratory illness that affects millions of people worldwide each year. It is characterized by symptoms such as fever, cough, sore throat, body aches, and fatigue, the flu can range from mild to severe and can lead to complications, especially in vulnerable populations. In this article, we explore the causes and symptoms of the flu, providing insights into how to stay healthy during flu season and minimize the spread of this contagious virus.
A general overview on flu
Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. The flu can vary in severity from mild to severe and can lead to complications, especially in vulnerable populations such as young children, older adults, pregnant women, and individuals with certain underlying health conditions.
Influenza viruses circulate worldwide and can cause seasonal outbreaks, usually peaking during the fall and winter months in temperate regions. According to the WHO, flu exerts a significant global burden, with approximately a billion cases of seasonal influenza occurring each year. Among these cases, there are an estimated 3–5 million instances of severe illness, indicating the substantial impact of the virus on public health.
Furthermore, influenza-related respiratory deaths range from 290,000 to 650,000 annually, underscoring the seriousness of the disease and its potential to lead to fatal outcomes. Vaccination is the most effective way to prevent the flu and reduce its spread. Treatment may include antiviral medications to alleviate symptoms and shorten the duration of illness, along with supportive care measures such as rest, hydration, and over-the-counter medications to relieve symptoms.
Symptoms of flu
- Fever or feeling feverish/chills
- Cough
- Sore throat
- Runny or stuffy nose
- Muscle or body aches
- Headaches
- Fatigue (tiredness)
- Vomiting and diarrhea (more common in children than adults)
Causes of flu
Flu is a complex infectious disease caused by influenza viruses and influenced by various factors related to the virus, the host, and the environment. Some of the common causes of the flu are discussed below;
- Influenza Viruses: The primary cause of flu is infection with influenza viruses, including types A, B, and C. These viruses are highly contagious and can spread easily from person to person.
- Respiratory Droplets: Flu viruses spread through respiratory droplets expelled when an infected person coughs, sneezes, or talks. These droplets can travel through the air and be inhaled by nearby individuals.
- Close Contact: Close contact with an infected person increases the risk of contracting the flu. This can occur through activities such as sharing utensils, kissing, or being in crowded spaces with infected individuals.
- Contaminated Surfaces: Flu viruses can survive on surfaces for a limited time, making it possible to contract the virus by touching contaminated surfaces and then touching the mouth, nose, or eyes.
- Crowded Living Conditions: Living or working in crowded environments, such as schools, nursing homes, or military barracks, increases the risk of flu transmission due to close contact with infected individuals.
- Environmental Factors: Certain environmental conditions, such as cold weather and low humidity, may promote the survival and transmission of flu viruses. Indoor heating and decreased ventilation during colder months can also facilitate the spread of the virus.
- Lack of Immunity: Individuals who have not been vaccinated against the flu or who have not previously been infected with influenza viruses may have limited immunity to the virus, making them more susceptible to infection.
Frequently asked questions
How does the flu spread, and what are the main modes of transmission?
The flu spreads through respiratory droplets produced when infected individuals cough, sneeze, or talk. These droplets can land in the mouths or noses of people nearby or be inhaled into the lungs. The virus can also spread by touching surfaces or objects contaminated with flu virus particles and then touching the mouth, nose, or eyes.
Who is at risk of developing complications from the flu?
Certain groups are at higher risk of developing severe complications from the flu, including young children, older adults, pregnant women, individuals with underlying health conditions (such as asthma, diabetes, or heart disease), and immunocompromised individuals.
Can antiviral medications help treat the flu?
Antiviral medications such as oseltamivir (Tamiflu) and zanamivir (Relenza) may be prescribed to treat flu infection and reduce the severity and duration of symptoms, particularly when started early in the course of illness.
Can I still get the flu after being vaccinated?
While flu vaccination is the best way to prevent the flu, it’s still possible to get infected with the flu virus, especially if you come into contact with a different strain of the virus not covered by the vaccine. However, vaccination can help reduce the severity of illness and prevent complications.
Sources
Influenza (seasonal). https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal)#:~:text=There%20are%20around%20a%20billion,650%20000%20respiratory%20deaths%20annually.
Boktor SW, Hafner JW. Influenza. [Updated 2023 Jan 23]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459363/
Chow, E. J., Doyle, J. D., & Uyeki, T. M. (2019). Influenza virus-related critical illness: Prevention, diagnosis, treatment. Critical Care, 23. https://doi.org/10.1186/s13054-019-2491-9
Rao, S., Nyquist, A., & Stillwell, P. C. (2018). Influenza. Kendig’s Disorders of the Respiratory Tract in Children (Ninth Edition), 460-465.e2. https://doi.org/10.1016/B978-0-323-44887-1.00027-4
