The MenB vaccine has been added to the NHS childhood immunization program for children born on or after 1 July 2015. Now it is offered to all children.
But this means teenagers and young adults over 11 have not received the jab.
Young children are vaccinated because they are more likely than other age groups to be exposed to invasive infections and their bodies are less likely to be able to fight them off.
However, research shows that the MenB vaccine does not necessarily prevent person-to-person transmission, does not work against all different strains of B bacteria, and does not provide long-term protection.
British vaccine experts have therefore concluded that it is not cost-effective to offer the MenB vaccine to all teenagers.
But they want everyone who is eligible to come forward and get the vaccine because it can prevent serious illness.
Around 10,000 people in the Kent region have already received vaccinations as part of the response to the outbreak in March.