Western Australia will soon become the first state to offer free meningococcal vaccinations for teenagers aged 15 to 19.

Injections are being rolled out in response to a “disturbing increase” in cases of the meningococcal W strain.

“The W strain increased to 14 cases last year from only four in 2015 and four in about the three years prior to that,” WA Health Minister John Day said over the weekend. .

“Experience in the United Kingdom and elsewhere suggests that, without effective intervention now, W infection rates will escalate.”

Of the three West Australian residents to die from meningococcal last year, two were from the W strain and one from the Y strain.

“All strains of meningococcal disease are potentially very serious but the W strain in particular really does take hold quite quickly,” Mr Day said.

The free vaccination will protect against strains A, C, W and Y.

“Teenagers in this age group are not only among the most susceptible, they are the biggest carriers of the meningococcal bacteria in the community,” Mr Day said.

“So targeting that age group is considered to have the most effect in reducing the incidents of the disease more widely across the community in other age groups as well.”

The three-year, multi-million-dollar program will start during the second school term in April.

Year 10, 11 and 12 students will receive the single dose vaccine at school, while 18 and 19-year-olds can receive them from community health clinics.

A vaccine against the C strain of the disease is already free.

A targeted ACWY vaccination program was set up in Kalgoorlie after five cases of the W strain were recorded over a two-month period late last year.

Meningococcal bacteria are carried harmlessly in the back of the nose and throat by about 10-20 per cent of the population at any one time

On rare occasions, the bacteria invade the bloodstream and cause serious infections.

With appropriate treatment, most people with the disease recover, although about 5 per cent will die and about 15 per cent may experience complications such as hearing loss, or gangrene requiring skin grafts or amputations.

More information is available from WA Health.