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Meningococcal group B (MenB)

Meningococcal disease usually occurs as meningitis or sepsis (blood poisoning).

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Meningitis can affect anyone, but is most common in babies, young children, teenagers and young adults. It can cause life-threatening sepsis and result in permanent damage to the brain or nerves. There are 12 known groups of meningococcal bacteria (Neisseria meningitidis). Meningococcal group B (MenB) is responsible for about 9 in every 10 meningococcal infections in the UK.

More information about meningococcal disease and signs and symptoms: NHS 111 Wales - Meningitis (external site).

MenB vaccine

The MenB vaccine is the safest and most effective way to help protect against meningitis and sepsis caused by meningococcal bacteria group B.

You can find more information on the vaccine and the disease it protects against at: NHS 111 Wales - Vaccinations (external site).


Eligibility for the vaccine

Baby immunisations

As part of the routine immunisation programme in Wales, the MenB vaccine is offered to babies at:

  • eight weeks;
  • 16 weeks; and
  • 12 to 13 months (booster).

Non-routine immunisations

Some medical conditions increase the risk of severe infections. People who already have these conditions may need the MenB vaccine. The conditions include:

  • not having a spleen or having a spleen that doesn’t work very well (including due to sickle cell and coeliac disease); and
  • problems with the immune system (complement disorders).

If you have any questions about the MenB vaccine, or you are not sure about when your baby or child should have it, you can contact your GP surgery for advice.


About the vaccine

Babies will normally be given the MenB vaccination as an injection in their upper leg (thigh). Older children and adults will normally receive the MenB vaccination as an injection in their upper arm.

The MenB vaccine, Bexsero, is the only vaccine currently available in the UK that offers protection against meningococcal group B bacteria. 

Since September 2015, babies have been offered the MenB vaccine as part of the routine immunisation schedule in Wales. This is because the MenB vaccine is highly effective against serious infections caused by meningococcal group B bacteria.

Babies will need three doses of the MenB vaccine to be fully protected. Children who have missed vaccinations and received less than two doses of MenB vaccine in the first year of life should receive further doses before they reach two years of age.

If your child has missed any doses or you are in an at-risk group, speak to your GP or practice nurse for advice.

MenB vaccine is not routinely given to children over two years old unless they are in an at-risk group.

Vaccination is one of the most effective ways to prevent meningitis and blood poisoning (sepsis) caused by meningitis B infection. No vaccine is 100% effective, so it is still important to know the signs and symptoms of meningitis and sepsis, even if you or your child are vaccinated.  

For more information about meningitis and sepsis visit 

NHS 111 Wales - Health A-Z : Meningitis (external site) 

NHS 111 Wales - Health A-Z : Sepsis (external site) 

Side effects of MenB vaccine

The most common side effect seen with the MenB vaccine in babies is a fever, or high temperature. Other common side effects of the MenB vaccine include:

  • pain, swelling or redness at the site of the injection;
  • vomiting or diarrhoea (or both); and
  • crying and irritability.

It is recommended that babies are given infant liquid paracetamol to prevent fever after vaccination. The nurse will give you more information about paracetamol at your vaccination appointment.

It is a good idea to have some infant liquid paracetamol at home before the two-month vaccination visit. You can buy it from local pharmacies or supermarkets. Never give babies the higher-strength paracetamol liquid used for older children. Never give medicines that contain aspirin to a baby.

Other reactions are rare. For more information on common and rare side effects, see: NHS 111 Wales - Vaccinations (external site) and Bexsero.

If you are concerned about symptoms call NHS 111 Wales (external site). Calls to NHS 111 Wales are free from landlines and mobile phones.

You can report suspected side effects of vaccines and medicines through the Yellow Card scheme. You can do this online at or by calling the Yellow Card scheme hotline on 0800 731 6789 (Monday to Friday, 9am to 5pm).  


Information for the public

If you would like to learn more about the MenB vaccine or the diseases it protects against, a number of information resources are available to help. You can also call NHS 111 or your GP practice for advice if you have any questions.



Further information

Meningitis Research Foundation is a leading UK, Irish and international charity that brings together people and expertise to defeat meningitis and sepsis.

Meningitis Now is a national meningitis charity based in the United Kingdom.