Mumps

Notification requirement for mumps

Mumps is a 'routine' notifiable condition. It must be notified by medical practitioners and pathology services to the Department of Health in writing within 5 days of diagnosis.

This is a Victorian statutory requirement.

Primary school and children's services exclusions for mumps

Children with mumps must not go to primary school and children's services for 5 days or until swelling goes down (whichever is sooner).

For more information, see the School exclusion table.

Infectious agent of mumps

Mumps virus is a member of the Paramyxoviridae family.

Identification of mumps

Clinical features

Mumps is an acute febrile disease that often has a prodrome of low-grade fever, malaise, headache and anorexia, followed by swelling and tenderness of one or more of the salivary glands, usually the parotid and occasionally the sublingual or submaxillary glands.

Respiratory symptoms can occur, particularly in children under 5 years old.

It may also present with only non-specific or primarily respiratory symptoms. Subclinical and asymptomatic infections can also occur. Differential diagnosis include swelling of the lymph nodes of the neck.

Mumps can occur in people who are fully vaccinated – although these people are less likely to present with severe symptoms or complications than those who are not fully immunised. Therefore, clinicians should consider mumps in all people presenting with compatible symptoms, regardless of vaccination status, age or travel history.

Complications

Mumps is usually a mild, self-limiting illness that people recover from within a few weeks without sequelae. Although uncommon, complications from mumps can occur and may include meningitis, encephalitis, pancreatitis, mastitis, myocarditis, hepatitis, thyroiditis, and hearing loss.

Orchitis occurs in up to a third of post-pubertal males and is most commonly unilateral.

Oophoritis occurs in about 5% of adult females. Sterility following infection is a rare.

Mumps during the first trimester may increase the risk of spontaneous abortion, but there is no evidence that mumps during pregnancy results in congenital malformations.

Diagnosis

The predictive value of parotitis in the diagnosis of mumps is reduced in countries with high immunisation rates, such as Australia.

Many viral infections produce a parotitis with a similar clinical picture to mumps, including Epstein-Barr, parainfluenza, coxsackie and influenza A viruses. Therefore, testing is highly recommended to confirm or exclude mumps as the causative agent.

The diagnosis should be confirmed via:

• Serology: detection of mumps-specific IgM antibody or a significant rise in mumps IgG antibody in acute and convalescent sera.
• PCR testing: detection of mumps virus RNA by polymerase chain reaction (PCR), suitable within the early stages of illness. Suitable specimens for PCR testing include oral fluid, parotid duct (buccal) swabs, urine and cerebrospinal fluid.
• Viral culture: from oral fluid, parotid duct (buccal) swabs, urine or seminal fluid and cerebrospinal fluid within the first week of illness.

PCR testing for mumps is undertaken at the Victorian Infectious Diseases Reference Laboratory (VIDRL) and is not Medicare funded. Approval for testing costs can be obtained from your Local Public Health Unit (on behalf of the department).

Incubation period of mumps virus

The incubation period ranges from 12 to 25 days. It is commonly 16 to 18 days.

Reservoir of mumps virus

Humans.

Mode of transmission of mumps virus

Transmission occurs through respiratory droplets, aerosol, by direct contact with contaminated saliva or urine, or via contaminated fomites.

Period of communicability of mumps

Mumps virus has been isolated from saliva from 7 days before the onset of salivary gland swelling to 9 days afterwards. However, maximum infectiousness occurs between 2 days before and 5 days after onset of salivary gland swelling. Asymptomatic cases can also be infectious.

Susceptibility and resistance to mumps

People are at increased risk of mumps infection if they are not fully immunised or do not have immunity from a previous mumps infection.

Two doses of a mumps-containing vaccine are recommended for protection.

Natural infection, even when subclinical, usually provides lifelong immunity.

Individuals born before 1966 have a high likelihood of natural immunity, even if they have had no history of clinical infection.

Public health significance and occurance of mumps

Occurrence is worldwide.

There is generalised spread of the infection in communities with low immunisation rates; serologic studies show 85% or more of individuals in those communities have evidence of previous mumps infection by adult life.

High childhood immunisation rates in Australia have resulted in a dramatic reduction in rates of mumps infection. Between 2015 and 2019, the national notification rate for mumps was around 2.5 per 100,000 population. Peak incidence rates were reported in young and middle-aged adults. These people may have missed mumps vaccinations as a child and were born at a time when circulating disease was low.

Large outbreaks occurred in Western Australia (2014-2016) and Queensland (2017-2018)

Similar to Australia, the United States and Europe have had mumps outbreaks, where the peak rates of disease have been in the 18 to 24 years age group.

Control measures for mumps

Preventive measures – immunisation

Vaccination is the most important preventive measure against mumps as it reduces the risk of infection and severe illness.

Mumps-containing vaccines are live attenuated vaccines. In Australia, mumps vaccine is only available in combination with:

• measles and rubella vaccine (MMR) or
• measles, rubella and varicella vaccine (MMRV) - not recommended for people aged 14 years and over.

The National Immunisation Program Schedule offers free mumps-containing vaccine for:

• children at 12 months of age (given as MMR vaccine)
• children at 18 months of age (given as MMRV vaccine)
• catch-up for people under 20 years who did not receive mumps-containing vaccine in childhood
• catch-up for refugees and humanitarian entrants aged 20 years and over.

Unless specific contraindications to live vaccines exist, all people born during or since 1966 should have either:

• documented evidence of 2 doses of mumps-containing vaccine given at least 4 weeks apart and with both doses given ≥12 months of age, or
• serological evidence of immunity to measles, mumps and rubella.

In Victoria, one or 2 doses of free MMR vaccine is also available for all people born during or since 1966 without evidence of receiving 2 documented doses of valid MMR vaccine or without serological evidence of immunity.

The 2 doses of mumps-containing vaccine should be given at least 4 weeks apart and with both doses given at ≥12 months of age.

Mumps-containing vaccines are contraindicated in pregnant women. Vaccination should be deferred until postpartum. Breastfeeding women can receive the MMR vaccine. Vaccinated women should avoid pregnancy for 28 days following vaccination.

Mumps-containing vaccines are also contraindicated in people who are immunocompromised. See the Australian Immunisation Handbook, Vaccination for people who are immunocompromisedfor more details.

For further guidance on vaccination refer to Australian Immunisation Handbook, Mumps.

Control of case

There is no specific treatment for mumps. Cold or warm packs applied to swollen glands may provide relief. Simple analgesic agents, such as paracetamol may help to reduce fever or pain.

Cases requiring hospitalisation should be nursed in an isolation room using respiratory precautions for 5 days or until the swelling goes down (whichever is sooner).

Exclude cases from school, childcare or workplace for 5 days or until swelling goes down (whichever is sooner). Advise parents to keep the child away from other children and susceptible adults for the period of exclusion.

Control of contacts

Close contacts of all cases who have not received 2 doses of MMR vaccine should be encouraged to get immunised, provided there are no contraindications. While this may not prevent mumps from occurring, it can reduce likelihood of infection upon future exposures. Immunoglobulin is not an effective post-exposure prophylaxis measure and is not recommended for contacts.

Control of environment

Practise concurrent disinfection of articles soiled with nose and throat secretions. There is some evidence that mumps can survive on surfaces (as fomites) so cleaning with detergent is important, especially for horizontal surfaces. For further information, refer to the Australian Guidelines for the Prevention and Control of Infection in Healthcare.

Outbreak measures for mumps

Susceptible people should be immunised, especially those at risk of exposure. People born during or since 1966 who are not certain of their immunity are recommended to receive the mumps-containing vaccine if no specific contraindications to live vaccines exist. People born before 1966 do not need to receive the mumps-containing vaccine (unless serological evidence indicates that they are not immune).