MenB Vaccine (Meningococcal B Vaccine)

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Meningococcal disease is caused by the bacterium Neisseria meningitidis. It causes a range of serious, life-threatening diseases including septicaemia (blood poisoning) and meningitis (an infection of the protective covering of the brain and spinal cord). It can affect all age groups, but the rates of disease are highest in children under five years of age, and the highest rates are seen in babies under one year of age.

The MenB vaccine protects against infection by group B meningococcal bacteria. In the last 10 years, about 90% of the cases of meningococcal disease in the UK were caused by group B infections. Before the MenB vaccine was introduced, around 600 people a year in the UK, mainly babies and children, were infected by MenB.  About 10% of those cases were fatal.

In the UK it is recommended that babies receive one dose of the MenB vaccine at 8 weeks, 16 weeks, and one year of age.  The vaccine does not contain any live bacteria and cannot cause meningococcal disease.

The UK was the first group of countries in the world to introduce a MenB vaccine into its national programme using the Bexsero vaccine, which has shown to be very effective in preventing MenB disease in infants and young childrensince it was implemented into the UK’s national infant immunisation programme in September 2015. It has also been proven to give protection against other types of meningococcal disease, such as some strains of MenW (see more information section below).

The Joint Committee on Vaccination and Immunisation (JCVI) advises the UK government on vaccination and immunisation have recently suggested that the MenB vaccine should be used in a targeted programme to prevent cases of gonorrhoea.  Evidence has shown that the MenB vaccine provides some protection against gonorrhoea which is caused by gonococcal bacteria that are closely related to meningococcal bacteria. Read the JCVI statement here.

The new MenB vaccine in the UK


In the UK, the MenB vaccine is given to babies at 8 weeks, 16 weeks, and one year of age. Your GP surgery or clinic will send you an appointment for your baby to have their MenB vaccination along with their other routine vaccinations. 

Additional doses of the vaccine are recommended for people with some long-term health conditions who are at greater risk of more severe meningococcal disease. This includes people with:

  • asplenia or splenic dysfunction (a spleen that is missing or does not work properly)
  • sickle cell anaemia
  • coeliac disease
  • complement disorders (the complement system is an important part of the immune system, and disorders of this system can increase a person’s risk to some diseases.)

The JCVI also advise that the MenB vaccine should be offered through sexual health services to those who are at increased risk of infection with bacterial sexually transmitted infections.  


Like all vaccines, the MenB vaccine can cause side effects, although not everybody gets them.  The vaccine used in the UK is called Bexsero, and the following side effects may occur in infants and children up to 10 years of age:

Very common, these may affect more than 1 in 10 babies:

  • fever (≥ 38 °C),
  • loss of appetite,
  • tenderness at the injection site (including severe injection site tenderness resulting in crying when injected limb is moved),
  • painful joints,
  • sleepiness,
  • feeling irritable,
  • unusual crying,
  • diarrhoea,
  • headache,
  • vomiting (uncommon after booster),
  • skin rash (children aged 12 to 23 months) (uncommon after booster).

Common, these may affect up to 1 in 10 babies:

  • skin rash.  

Uncommon, these may affect up to 1 in 100 babies:

  • high fever (≥ 40 °C),
  • seizures (including febrile seizures),
  • dry skin,
  • paleness (rare after booster).

Rare, these may affect up to 1 in 1,000 people:

Kawasaki disease, which may include a range of symptoms e.g. a fever that lasts for more than five days. However, recent studies have found that there is no evidence to suggest that there is an increased chance of developing Kawasaki disease after receiving the MenB vaccine. See more here.


The following side effects may occur in adolescents from 11 years of age and adults:

Very common, these may affect more than 1 in 10 people:

  • pain at the injection site resulting in inability to perform normal daily activity,
  • painful muscles and joints,
  • nausea,
  • generally feeling unwell,
  • headache.

Very common side effects that may affect more than 1 in 10 people, that were reported in all age groups:

  • pain/tenderness at the injection site
  • redness of the skin at the injection site
  • swelling of the skin at the injection site
  • hardness of the skin at the injection site.


As with any vaccine, medicine or food, there is a very small chance of a severe allergic reaction (anaphylaxis). Anaphylaxis is different from less severe allergic reactions because it causes life-threatening breathing and/or circulation problems. It is always extremely serious but can be treated with adrenaline. Healthcare workers who give vaccines know how to do this.

In the UK between 1997 and 2003 there were a total of 130 reports of anaphylaxis following ALL immunisations. Around 117 million doses of vaccines were given in the UK during this period. This means that the overall rate of anaphylaxis is around 1 in 900,000.

If you are concerned about any reactions that occur after vaccination, consult your doctor. In the UK you can report suspected vaccine side effects to the Medicines and Healthcare products Regulatory Agency (MHRA) through the Yellow Card Scheme.

You can also contact the MHRA to ask for data on Yellow Card reports for individual vaccines. See more information on the Yellow Card scheme and monitoring of vaccine safety.


Bexsero, the MenB vaccine used in the UK, contains different proteins taken from group B Neisseria meningitidis bacteria. There are three major proteins taken from the surface of most meningococcal bacteria that are combined with the outer membrane of one MenB strain.  The combination of proteins was chosen to protect against the majority of MenB strains, rather than one specific strain.

Apart from these active ingredients (the antigens), the vaccine contains very small amounts of these ingredients:

  • Aluminium, which strengthens and lengthens the immune response to the vaccine
  • salt (sodium chloride)
  • sugar (sucrose) and an amino acid called histidine, both used as acidity regulators. (Amino acids are the building blocks of proteins.)

The vaccine may also contain traces of these products used during the manufacturing process:

Latex may be used in the packaging of Bexsero.

Other brands of MenB vaccine used in other countries may contain different ingredients. If you are not in the UK, ask for the patient information leaflet for the vaccine you are offered.


Charlotte Nott developed septicaemia through type B meningococcal disease infection. In the short film below, her mother, Jenny Daniels, talks about the impact on Charlotte and the rest of her family.


Meningococcal Septicaemia (MenB) - Charlotte's story

Click here for an accessible text version of this video


How well does the vaccine work?

A new study by Public Health England shows that infant vaccination against MenB has resulted in a significant decline in cases of the disease in young children since the programme was introduced.

The study shows that by the third year of the programme, cases of MenB disease were 62% lower in children who were eligible for at least 2 doses of the vaccine. Between 2015 and 2018, an estimated 277 out of an expected 446 cases were prevented because of the programme.

Read the full study here: Vaccination of Infants with Meningococcal Group B Vaccine (4CMenB) in England

Meningococcal clusters and outbreaks

Although most cases of meningococcal disease are sporadic, occurring infrequently or in isolated scenarios, outbreaks of the disease can occur within communities, such as in schools and universities.

In an outbreak, the vaccination used must be appropriate to the strain of infection spreading. Therefore, a different vaccine to the one offered within the UK immunisation schedule may be used.

For example, the MenB-fHbp vaccine (Trumenba) may be used if Bexsero, the vaccine usually used in the UK, is predicted not to be suitable. Trumenba is only available privately in the UK.

The patient information leaflet for Trumenba can be found here.

Policy decision around the cost-effectiveness of the MenB vaccine

In September 2015, the UK included the MenB vaccine in the routine immunisation schedule. This decision was made by the Joint Committee on Vaccination and Immunisation (JCVI) – the committee that advises the UK government on vaccines. Initially, the evidence available to them suggested that this vaccine would not be cost-effective, however after further analysis, the JCVI statement from 2014 suggests that the vaccine could be cost-effective if the vaccine could be supplied at a low cost. This led to the recommendation that this vaccine should be included within the UK schedule if it could be purchased at a low cost.

Read the 2014 JCVI statement here

Bexsero is approved for use in various countries, including Argentina, Australia, New Zealand, and Turkey, but the borderline cost-effectiveness of this vaccine means that it is yet to be introduced into some immunisation schedules internationally.

MenB vaccine to protect against gonorrhoea

The JCVI have recently suggested that the MenB vaccine should be used in a targeted programme to prevent gonorrhoea.  Cases are currently at a record high in the UK and this recommendation should help to reduce this.

Meningococcal disease (Neisseria meningitidis) and gonorrhoea (Neisseria gonorrhoeae) are closely genetically related, with evidence showing that the MenB vaccine provides some cross-protection against gonorrhoea (between 32.7% to 42%).

This advice will now be considered by the Department of Health and Social Care before any policy decisions are made on any new routine immunisation programmes.

Read the JCVI statement here.


Page last updated Monday, November 21, 2023