Flu Causes
What causes the flu?
The flu is an upper respiratory tract infection(URTI) caused by the influenza virus,2,3 typically types A and B, which cause seasonal epidemics every year.
Type C is detected less often and usually causes mild symptoms.1
Transmission of the Flu
Influenza virus particles are spread from person to person within tiny droplets formed when coughing, sneezing, or talking.4-6
These infected droplets are then transmitted to another person who either5,6:
- Breathes in the airborne droplets.
- Comes into close contact with an infected person.
- Touches a contaminated surface and then touches their mouth, nose, or eyes.
Anyone can get the flu, but it can be more serious in certain groups of people1:
- People aged 65 and over.
- Pregnant women.
- People with serious medical conditions such as diabetes, HIV, chronic respiratory, cardiac or cancer conditions.
- Babies/young children.
-
The Contagious Period
![Colleagues at work]()
How long is flu contagious?
An infected person may be able to spread the flu before even becoming symptomatic.4
The highest point of contagiousness is within the first 3-4 days after the illness begins, but most adults may be considered infective 1 day prior to demonstrating symptoms.4
Healthy adults can be capable of spreading the virus for up to 7 days into their flu episode, but children and immunocompromised patients may be contagious for a longer period.4
-
Reducing Risk
Reducing the risk of contracting the flu
Due to the constantly evolving nature of influenza viruses, the composition of the flu vaccine is updated every year as necessary.7
In addition to this, patients can be counselled to reduce their risk of infection and the risk of spreading it to others.
![Woman blowing her nose]()
1. Use a tissue to cover coughs and sneezes
Cough or sneeze into a tissue, and then immediately dispose of it.8
![Washing your hand]()
2. Wash your hands regularly
Wash your hands regularly and thoroughly with soap and water for at least 20 seconds. If soap and water is not available, use an alcohol-based hand sanitizer.8
![Woman touching her face]()
3. Avoid touching your face
The flu virus can be caught through the process of “self-inoculation”, which refers to a person touching an infected surface and then transferring virus particles to themselves by touching their eyes, nose, or mouth.5,8
Where possible, avoid touching your face.
![Close up of cleaning home wood table]()
4. Routine cleaning
The flu virus can “live” on some surfaces for up to 48 hours. Routine cleaning of surfaces can help to reduce the spread of flu.9
![Man sitting on a sofa holding a mug of coffee]()
5. Self isolation
Avoiding close contact with people that are ill and early self-isolation of those feeling unwell is recommended.
For those who have been ill with flu symptoms, remaining isolated for at least 24 hours after their fever is gone is also advised.10
How does climate change affect the spread of influenza?
There is a growing amount of work investigating the links between climate change and respiratory diseases such as influenza, helping to ensure medical and public health experts are prepared for any future challenges.11
Viral respiratory tract infections are the most common human illness, with approximately 17bn incidences recorded in 2019.11
Studies have shown what most health professionals may understand well: with lower temperatures, the likelihood of influenza rises.11,12 A similar association was seen with humidity, where a lower absolute humidity also led to a rise in influenza.12
Warmer winters were also found to be linked to more severe epidemics of influenza A and B the following year.11 And in tropical climates, increased temperatures were associated with higher rates of respiratory infections.11
Multiple studies have also shown that when extreme precipitation (snow, rain, hail) events occur, influenza cases often rise shortly afterwards.13-18
Being aware of the climate or weather changes that are occurring, as well as their severity, could help you plan for a potential rise in patients seeking flu medications.
Panadol – the Power to Feel Better
