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How Long are You contagious for When You Have a cold?


How long you have been sick can be a good indicator of how contagious you are. With a common cold you will generally be infectious for about three days after the onset of symptoms. This differs with influenza, which can see you being infectious for longer sometimes up to a week.

The natural course of infection can be divided into 3 phases:

– Incubation (infection without symptoms)

– Symptomatic (infectious with symptoms)

– Recovery (noninfectious with symptoms)

The incubation period last for a day or so with influenza this might be as little as a few hours with a common cold. During this time you can spread the infection but there a no signs or symptoms making it hard to protect ourselves.

During the symptomatic phase symptoms such as coughing and sneezing are a warning sign to avoid direct contact with a sick person, particularly to their respiratory secretions. This can be from 3 days with a cold and up to 7 days for influenza.

The recovery phase begins within about a week. During this time patients may still have symptoms like a cough or fatigue but are no longer infectious to others.


Janine Round

This post was written by Dr Janine Symington.

You can find out more about her here or book an appointment online here.

Alternatively, you can call us at the Clinic on 03 9908 2844.

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