A second WA child has been hospitalised with meningococcal disease in just two weeks, prompting another warning from health authorities about the potentially deadly infection.

WA Health issued the warning on Friday after the latest child was diagnosed with the serogroup B strain, which can be prevented with a vaccine.

There have been six cases of meningococcal disease reported in WA so far this year, down from 13 at the same time last year.

The vast majority of this year’s cases have been the B strain.

WA Health said meningococcal bacteria were not easily spread from person to person and were carried harmlessly in the nose and throat by about 10 to 20 per cent of people at any given time.

In rare cases, the bacteria can invade the bloodstream or tissues and cause serious infection.

Children in WA receive the MenACWY vaccine, which protects against strains A, C, W and Y, for free in their first year of life.

Year 10 students and teenagers aged 15 to 19 can also receive the MenACWY vaccine for free.

Because meningococcal disease occurs at higher rates among Aboriginal children in WA, MenACWY is also offered free to Aboriginal children aged six weeks to 12 months.

The MenB vaccine is free for all Aboriginal children up to two years old.

About 5 to 10 per cent of meningococcal infections can be fatal, while about 15 per cent of cases result in long-term complications.

Symptoms can include a high fever, chills, headache, neck stiffness, nausea, vomiting, drowsiness, confusion, severe muscle and joint pain and a red-purple spotty rash.

In babies and young children, symptoms can also include lethargy, poor feeding and a pale or blotchy complexion.

A WA adult died after contracting a serogroup Y infection in July.