Skip to main content
Dame ligt ziek in bed

What are the symptoms of flu?

Influenza is an inflammation of the respiratory mucus membranes. It is not a harmless cold virus. Most people will experience mild to moderate illness, but every year some of the patients end up in hospital with a serious infection.

Typically, flu often develops very suddenly, and symptoms can include:

  • shivering
  • headache
  • intense muscle ache and fatigue
  • sore throat and dry cough
  • fever

The fever can rise to 39°C or higher within 12 hours and usually persists for three to five days.

How is flu transmitted?

The influenza virus is highly contagious and present in saliva, phlegm, and mucus. Sneezing and coughing spread virus droplets in the air and these may then be inhaled by anybody nearby. One to two droplets is enough to transmit the virus. The influenza virus can remain infectious on non-porous surfaces such as door handles for as long as 24 to 48 hours. Porous surfaces such as handkerchiefs remain infectious for up to 12 hours. The virus can also be spread by touching infected objects. In addition to airborne transmission, spread by hand-to-hand contact is an important risk factor.

The incubation period for influenza is one to two days. People with the flu are contagious on the day before the onset of symptoms up to five days after they first developed symptoms. This may be longer in children. 

How to prevent flu?

Try to prevent infection by:

  • Touching your nose, eyes, and mouth as little as possible.
  • Using paper tissues.
  • Washing your hands frequently with soap and water.
  • Ventilating well.
  • Cleaning door handles, taps, and hand rails frequently.
  • Getting vaccinated against flu (the flu shot).

The flu vaccine 

As viruses multiply, they can change a little (mutate). As a result, we can become infected by a new virus every year, and this is why a new flu vaccine is needed every year. The new vaccine matches the latest virus strains as closely as possible.

A flu vaccine can protect us all, but people with poor health will receive an invitation from their GP to get a free vaccine. People who do not fall into the high-risk group can also be vaccinated but they will have to pay for the vaccine themselves. One place you can get the shot is at Travel Clinic Erasmus MC.

Why get a flu vaccine?

  • Flu affects one in ten people every year.
  • The risk of infection is greatest in confined areas that lots of people pass through, such as offices, public transport, schools, and daycare centers.
  • About half of the influenza infections are asymptomatic.
  • Influenza infections raise the risk of a heart attack by ten times in the week after having flu.
  • The flu vaccine can reduce the risk of heart attack by 15-45%. A similar reduction in heart attack risk is observed if people stop smoking (32-43%), use statins for elevated cholesterol, and get treatment for high blood pressure (17-25%).
  • The flu shot reduces the likelihood of getting flu by about 40% and the vaccine is different every season.
  • If you do catch the flu after a flu shot, it will be milder.