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Can I infect other people?

On this page, we explain how infectious TB is, how TB spreads and how to stop it spreading to other people, and what to do if you think you’ve been exposed.

If you have active TB in your lungs, you can 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 doctor or 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.

How can I reduce the risk of passing TB onto other people?

Your specialist TB team 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, dispose of your tissues carefully and then wash your hands. You may be asked to stay at home and have no new visitors. This is usually for two weeks, but it can be longer. After two weeks of effective, modern treatment you are usually no risk to other people. But you should not return to work, school or college until your specialist confirms you can do so safely.

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

What about the people I live or work with?

TB is a notifiable disease. This means that if you are diagnosed with active TB, it’s very important the people you spend a lot of time with are offered testing for active or latent TB. You’ll be asked for details of people you live with and other people you spend a lot of time with, including work colleagues. It is important to give this information to reduce the risk of other people getting unwell.

Not everyone you may have been in contact with will require testing. Your specialist will determine this. 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 you are far less likely to be infectious to others.

If you have latent TB, you are not infectious.

Tips for staying at home

If you need to stay at home, there are things you can do to prepare and limit the spread of TB:

  • Plan ahead to make sure you have everything you need to stay at home for the full duration of isolation. For example, food and any medicines you take.
  • Do not have any new visitors to your home.
  • Reschedule any routine appointments, such as the dentist. If you think the appointment is urgent, you should phone them in advance to discuss.
  • Avoid public transport and don’t go to any public places.

It is generally OK to continue living with the same people as before your diagnosis. They’ll automatically be contacted by your nurse for TB screening tests. However, you might need to isolate from your family if you live with young children or people with a weakened immune system. If this is the case, talk to your TB team about the best ways to do this.

While in home isolation, it’s important you take care of your mental well-being:

  • Stay in touch with friends and family over the phone or on social media
  • Spend time doing things you enjoy. This could be reading, listening to the radio or watching TV
  • If you feel well enough, try and do some physical exercise. Take a look at our online exercise videos or the NHS website
  • Try to eat healthily and drink plenty of water

What should I do if I think I’ve been exposed to TB?

If you think you’ve been exposed to TB, you should ask your health care professional to refer you to a TB specialist. To be infected, you would have to spend prolonged periods (several hours) in close contact with an infected person. You can only become infected by breathing in TB bacteria – you cannot get TB from someone’s clothes, cutlery, glass, toilet, handshake or surfaces they’ve touched.

The BCG vaccination

The BCG vaccination helps your body’s defences fight off TB. It is only given once. It is most effective at protecting young children from the severest forms of TB. Its protective effect wears off as you get older.

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 high incidence of TB
  • all infants (aged 0-12 months) living in areas of the UK with a high incidence of TB
  • unvaccinated people going to a country with a high incidence of TB
  • health care professionals who are likely to be exposed to TB bacteria, including medical students

Next: Treatment for TB >

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Download our tuberculosis PDF (73KB)

Last medically reviewed: September 2020. Due for review: September 2023

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.