Why is MenB vaccine not given to teenagers in UK and should they be offered it?

More cases of meningitis have been confirmed in Kent, bringing the total to 18 people with the illness and 11 others suspected of having the disease, the UK Health Security Agency says.
A targeted vaccination campaign for some University of Kent students has been extended to cover more people, including everyone in the area who has been offered precautionary antibiotics.
It comes after two young people’s deaths in Canterbury.
Meningitis B, known as MenB, is the strain of bacteria behind the outbreak.
Babies have been offered a vaccine against MenB since 2015, but most of the UK’s current generation of older teenagers and university students have not had it, as the jab was not available when they were born.
UK advisers decided against running a widespread catch-up campaign to vaccinate teenagers, but some parents have tried to buy the jab privately. Who is right?
Teenagers are currently offered a separate meningitis vaccine – the MenACWY vaccine – which protects against some other strains, but not MenB.