Frequently asked questions about flu

Reading time: 3 min
Is flu or influenza contagious and for how long?

Yes. Flu or influenza is a very contagious illness. One person with influenza can infect others from the day before they notice flu symptoms up until 5–7 days after the onset. Young children and people with a compromised immune system can transmit the virus for longer periods.

Can flu be serious?

In some cases, particularly in people with a high risk of being infected (children under the age of 5, pregnant women, elderly adults and people with chronic diseases), flu can manifest in a more severe form and lead to complications which require the patient’s admission to hospital for optimal medical management.

What tests might they do if I have flu or influenza?

An otherwise healthy person who has flu generally goes through the flu process without needing treatment or diagnosis of the type of influenza virus. This is because the diagnostic results would not change the treatment, which usually involves hydration, fever control measures and rest.

Patients that need hospitalisation will complete a rapid influenza diagnostic test and blood test to learn about your condition and the severity of the infection. In some cases of suspected complications such as pneumonia, the doctor may ask for a chest X-ray to confirm the pneumonia and obtain information about the location of the infection and other pulmonary complications such as fluid in the space around the lungs (pleural effusion). Healthcare staff will also measure your blood oxygen levels to determine if you need oxygen.

Why do I need to be hospitalised?

When flu courses with potentially life-threatening complications, you should be admitted to hospital because it is the safest means of monitoring your vital signs (heart rate, breathing rate, temperature) and ensuring that you respond correctly to the treatment established for the influenza virus infection.

Under certain circumstances, isolation may be necessary to protect both the flu patient and other patients in the hospital who may be at risk of infection since flu is very contagious, especially in the first few days after the symptoms develop.

How long will I have to stay in hospital?

If the flu infection is not too severe and with few complications, you may be discharged after 3–4 days. However, there are a lot of factors that contribute to the length of each hospital stay such as your immunological status, whether you have any underlying chronic diseases or develop any flu-related complications.

What are antivirals and why do I need them?

Antivirals are medications used to eliminate influenza viruses and, in general, they stop viruses from replicating, which helps control the infection. If they are administered in the first few days after the appearance of symptoms, they can reduce the length of the flu process. Antivirals have to be prescribed by a healthcare professional, as they can have side effects.

Remember: antibiotics are ineffective against flu because it is caused by a virus and antibiotics do not have any effects on viruses.

Should I stay in bed when I return home?

Rest is an important recommendation, but you should still try to follow your normal routine and exercise a little, if possible and so long as your healthcare professional does not tell you otherwise. The best solution is to find a balance between periods of rest and activity throughout the day. Follow an appropriate rhythm. Try to get out of bed and be active but without tiring yourself out.

Should I continue the hospital treatment at home?

Your healthcare professional will probably prescribe some medicines for you to take, although this depends on the specific characteristics of each patient. It is very important to follow the doctor’s indications and attend your scheduled visits.

Substantiated information by:

Anna Llupià
Antoni Trilla
Catia Cillóniz Campos
Gemina Santana

Published: 10 March 2020
Updated: 10 March 2020

The donations that can be done through this webpage are exclusively for the benefit of Hospital Clínic of Barcelona through Fundació Clínic per a la Recerca Biomèdica and not for BBVA Foundation, entity that collaborates with the project of PortalClínic.


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