Can I infect other people?

If you have active TB in your lungs, you will be infectious.

How infectious you are depends on:

  • if you are coughing
  • how much of your lung is affected
  • how many TB bacteria are in your phlegm

If your specialist health care professional says you have sputum smear positive TB, you have a lot of TB bacteria in your phlegm and you are very infectious.

Your specialist will tell you how infectious you are and how to reduce the risk of infecting other people.  

Simple advice is to cover your mouth with a tissue when you cough, then wash your hands and dispose of your tissues carefully. You may be asked to stay at home and have no new visitors. This is usually for two weeks. After two weeks of effective treatment you are usually no risk to other people. But you should not return to work, school or college until your specialist confirms you are no longer infectious.

As TB bacteria is spread by breathing in droplets with TB bacteria, there is no need to use separate dishes or cutlery.

You’ll be asked for details of people you live with and other people you spend a lot of time with so they are offered testing for active or latent TB. Sometimes your work colleagues may be offered tests to see if they have TB. It is important to give this information to reduce the risk of other people getting unwell. Your details will not be shared with your contacts by your health care professionals.

If you have active TB but it is not in the lungs or you have latent TB, you are not infectious.

The BCG vaccination

The BCG vaccination helps your body’s defences to fight off TB. It doesn’t protect you completely from TB. It is most effective at protecting young children from the severest forms of TB. Its protective effect wears off as you get older. It is only given once.

There is currently a global shortage of BCG for vaccination. In the UK, highest priority is to vaccinate:

  • all infants (aged 0-12 months) or previously unvaccinated children aged one to five years with a parent or grandparent born in a country with a lot of TB
  • all infants (aged 0-12 months) living in areas of the UK with a lot of TB

Next: Treatment for TB

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Last medically reviewed: September 2017. Due for review: September 2020

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.