How long are you contagious with a cold?

When you are struck down with a cold it’s tempting to soldier on. But staying home is one of the most important things you can do to prevent your friends and colleagues from getting sick. 

So, when is it safe to venture back out again without spreading it?  

According to Medibank’s Group Medical Director and GP, Shona Sundaraj, contagiousness tends to drop away 5–7 days after cold symptoms develop.  

“It’s important to consider how you are feeling in your body,” she says. “If you still have symptoms like a headache, body aches, a temperature, runny nose and feelings of lethargy or tiredness, those are signs that you are still fighting the infection and could pass it onto others.”  

Read on to find out more about how long the common cold lasts, signs it’s still contagious and what you can do to relieve the symptoms.  

How long does a cold last? And when is it contagious?

Most colds last a few days to a week, but you can be contagious before you start showing symptoms. Here’s a break down of each stage:  

Incubation period

Lasts 1 – 3 days  

The incubation period is the time between coming into contact with a virus, and symptoms developing, says Dr Sundaraj. 

“During the incubation period the viral particles are getting inside cells and they're starting to replicate. That period will last for two or three days before the symptoms start to show.”  

Even though you don’t have symptoms, you may already be contagious. 

Symptomatic period 

Lasts 3 – 7 days 

The start of the symptomatic period is usually when you are most contagious.  

Symptoms can include a sore throat, runny or stuffy nose, headaches, a cough and tiredness. In some cases you may experience a mild fever. 

According to Dr Sundaraj symptoms usually last between 3 and 7 days.   

“If you have developed any new symptoms or had a fever in the last 24 hours, it’s a sign your body is still fighting the infection ad you are still quite contagious,” she added. 

Post-viral cough  

Up to 8 weeks 

A lingering cough is a common experience after a cold.  

“While it is very annoying, a post-viral cough it is not contagious,” says Dr Sundaraj. “The virus causes inflammation in your throat and lungs. When something irritates your airways, for example, when you are talking or taking in a big breath after exercise, it can lead to a cough.” 
 

READ MORE: Is the flu just a bad cold? Flu myths debunked. 

How does a cold spread? 

There are more than 200 viruses that cause the ‘common cold'. Some of the better-known ones include rhinoviruses and coronaviruses. 

 These viruses are very contagious, and spread through:   

• Coughing and sneezing: “If you’re infected with a cold virus, respiratory droplets, come out of your nose or mouth when you cough or sneeze,” says Dr Sundaraj. “The virus spreads when someone else ingests those respiratory droplets.”  

• Touching people, surfaces or objects: “Sometimes respiratory droplets can be transmitted to your hands. The cold virus can then be passed onto others when shaking hands, or shared surfaces like door handles, or the rails on public transport.”