Health authorities in Auckland are worried an outbreak of mumps is being fuelled by low vaccination rates.
Auckland Regional Public Health Service said there had been more than 130 cases of mumps in Auckland this year compared to 35 last year.
Almost 70 percent occurred in children and teens aged 10 to 19. Of the current cases, 80 percent of people were not fully vaccinated, it said.
While most people recover, over the last six months a number of people have suffered from severe complications caused by mumps.
Some teenage boys have been hospitalised for pain and swelling in their testicles, which in rare cases can result in infertility.
Some girls or women have had ovarian inflammation, and another person developed meningitis.
Auckland Regional Public Health Service said non-immune pregnant women who get mumps risk miscarriage in the first three months. In rare cases, it can cause permanent hearing loss.
It urged parents to check with their doctor to ensure their families' measles, mumps and rubella (MMR) vaccinations were up to date.
Mumps can spread quickly among those who are not immune, particularly in schools.
An individual with mumps at a secondary school could cause an outbreak, because immunity in that age group is well below the national average, Auckland Regional Public Health Service said.
The health service warned that children could be excluded from school if parents didn't organise vaccination quickly.
What is mumps?
- It is an infectious disease caused by the mumps virus
- It is spread from person to person by saliva or mucous from the mouth, nose or throat of an infected person through coughing, sneezing or talking, or through direct contact with infected saliva, such as touching a dirty tissue, door handle, or computer keyboard
- The best way to protect against mumps is vaccination with MMR. Two doses of MMR are approximately 88 percent effective at preventing mumps.
- What are the symptoms?
- Some people have very mild or no symptoms - about one third of infected people do not show any symptoms at all
- Early symptoms include: fever, headache, muscle aches, tiredness and loss of appetite. There can also be swelling and tenderness of the salivary glands
- Mumps can sometimes lead to serious complications such as the inflammation of the surrounding tissues of the brain, testicles and ovaries. Sterility, although rare, can occur. Deafness can occur among one in 15,000 mumps cases.