​​​​On this page

1. Summary
2. The disease
3. Risk assessment
   
4. Surveillance objectives
5. Data management
6. Communications
7. Case definition
8. Laboratory testing
9. Case investigation
10. Control of environment
11. Contact management
12. Special situations
13. References
14. Appendices

1. Summary

Public health priority

Urgent.

Case management

• Laboratory confirmation should be sought in all suspected cases. Appropriate specimens for genotyping should be collected from at least one case in each chain of measles transmission and all sporadic cases where possible.
• Cases, including suspected cases under investigation, should stay home (unless isolated in hospital) and should not attend school, early childhood education and care services or work from onset of symptoms to 4 days after onset of rash. Cases should avoid contact with susceptible persons, especially children <1 year old and immunocompromised persons.
• The source of each confirmed measles case should be determined as: imported, import- related or unknown ^[1]. A thorough epidemiological investigation should be conducted to limit the number of cases with unknown source.

Contact management

• Individuals who are not immunocompromised with 2 documented doses of MMR or documented evidence of measles infection or born prior to 1966 are considered immune.
• Individuals born during or after 1966 with <2 doses of MMR and who have no documented history of measles infection or serological markers of immunity are considered non-immune, i.e. susceptible. Recommend either immunisation or normal human immunoglobulin (NHIG) to defined contacts where indicated.
• Recommend either immunisation or normal human immunoglobulin (NHIg) to defined contacts where indicated.
• Exclude susceptible contacts from school, early childhood education and care services, healthcare settings, and other settings with high risk contacts.
• Ask contacts to be alert for signs and symptoms of measles and advise those who develop symptoms to telephone ahead before seeking medical review so as to avoid infecting others.
• Ask hospital Emergency Departments (EDs), medical practitioners, school principals and early childhood education and care services directors to report new suspected cases promptly to the local public health unit.

2. The disease

Infectious agents

The measles virus, a member of the genus Morbillivirus (a paramyxovirus).

Mode of transmission

Measles is transmitted by airborne droplets and direct contact with discharges from respiratory mucous membranes of infected persons and less commonly by articles freshly soiled with nose and throat secretions ^[2]. It is one of the most highly communicable infectious diseases. Measles virus has a short survival time (less than 2 hours) in the air or on objects and surfaces and is inactivated rapidly in the presence of sunlight, heat and extremes of pH^[3].

Incubation period

The incubation period is variable, about 10 days (varying from 7 to 18, occasionally longer) to the onset of fever and about 14 days to the onset of the rash. This period can be longer if immunoglobulin is given early in the incubation period ^[2].

Infectious period

Cases are considered to be infectious from 24 hours prior to onset of prodromal symptoms until 4 days after the onset of rash. Where the prodrome is undefined, the onset of the infectious period should be considered to be 4 days before the onset of the rash.

Clinical presentation and outcome

The disease is characterised by a prodrome that usually lasts 2 to 4 days and includes fever followed by conjunctivitis, coryza and cough. Koplik spots may be present briefly on the buccal mucosa. A characteristic maculopapular (non-itchy) rash appears about 2 to 7 days after the onset of the prodrome, and begins on the face or upper neck, spreads to become generalised and typically lasts 4 to 7 days. The rash is not itchy. Cases are usually very unwell and miserable; other symptoms can include anorexia, diarrhoea (especially in infants) and generalised lymphadenopathy^3. People who have received one or two doses of measles vaccine may develop attenuated infection with mild symptoms.

Common complications of measles include middle ear infection and viral or bacterial bronchopneumonia. Acute encephalitis occurs rarely and subacute sclerosing panencephalitis is a very rare delayed complication, occurring in about 1 per 100,000 cases ^[5].

Persons at increased risk of disease

Unvaccinated or under-vaccinated people (i.e. those who have not had two doses of measles containing vaccine) are at increased risk of measles.

Those at risk of more severe disease include ^[3]:

• immunocompromised people, especially those with T-cell deficiencies such as certain leukaemias, lymphomas and acquired immunodeficiency syndrome (AIDS), in whom measles can be severe, atypical (e.g. without rash) and prolonged, with virus shedding for several weeks after the acute illness
• malnourished children, particularly those with vitamin A deficiency
• children younger than 5 years and adults 20 years of age and older, in whom complications of measles are more common
• pregnant women in whom infection is associated with increased risk of premature labour, spontaneous abortion and low birth weight infants. Birth defects have not conclusively been associated with measles virus infection.

Disease occurrence and public health significance

Endemic transmission of measles ceased in Australia by the late 1990s as a result of the introduction of a two-dose vaccination schedule and by improved vaccination coverage. In 2014 the WHO verified that Australia had achieved ‘measles elimination’ status, defined as the absence of endemic transmission in a defined geographical area for ≥ 12months^1. Although measles is no longer endemic here, Australia continues to have imported cases in overseas visitors and returning residents, with the potential for limited transmission and small to moderate-sized outbreaks. Geographic areas and population sub-groups with low vaccination coverage are more susceptible to prolonged outbreaks and every attempt should be made to provide all children with two doses of measles-containing vaccine. Other than unvaccinated children, adults born during or after 1966 are at most risk due to less frequent exposure to wild-type virus and lower vaccination coverage ^[4]

3. Routine prevention activities

Vaccination

Maintaining high rates of immunity to measles throughout the population is the mainstay of measles elimination in Australia. Measles vaccine, as MMR and MMRV, is currently recommended for all children at ages 12 and 18 months of age, respectively, as part of the National Immunisation Program schedule^[5].

For persons born during or after 1966 who do not have documented immunity, two doses of measles-containing vaccine, given at least 4 weeks apart, are recommended. For those known to have received only one dose previously, a second dose is recommended.

Health facilities should ensure that healthcare workers and administrative staff are fully vaccinated or immune to measles, particularly those working with high risk persons such as children <1 year; pregnant and immunocompromised persons; and in high exposure risk areas such as emergency departments.

Immunisation recommendations for early childhood education and care service workers and overseas travellers should be promoted.

Outbreak control

Control of measles relies on early diagnosis and notification of cases, prompt isolation of infectious cases, and timely and effective identification of contacts, with provision of advice and post-exposure prophylaxis and/or quarantine, as appropriate. In defined groups of susceptible people, where exposure has occurred but it is too late or not feasible to identify individuals for whom post-exposure prophylaxis may prevent infection, widespread vaccination is sometimes indicated to minimise ongoing transmission within the group.

4. Surveillance objectives

• To rapidly identify cases and their contacts in order to prevent further spread
• To determine the source of each conformed measles case
• To monitor the epidemiology of measles in Australia in order to inform public health strategies and assess interventions
• To maintain a surveillance system that is sufficiently sensitive to detect sporadic cases
• To confirm measles elimination is sustained in Australia and to contribute to regional measles elimination goals
• To assist in identifying at risk groups and areas of under-immunisation.

5. Data management

• Probable and confirmed cases (see case definitions) should be entered onto the notifiable diseases database within 1 working day following notification.
• Enter viral genotype (where determined) on notifiable diseases database within 3 working days of receipt of results.
• In order to verify elimination status, information on suspected cases subsequently shown not to have measles (discarded cases) should be retained for national monitoring purposes, in accordance with jurisdictional protocols and data systems.
• If overseas acquired, enter place of acquisition (where determined) on notifiable diseases database in accordance with jurisdictional protocols and data systems.
• Assign each case in a chain of transmission of two or more epidemiologically linked cases a unique outbreak reference identification number that links all cases in the cluster and enter this on the notifiable diseases database in accordance with jurisdictional protocols and data systems.

6. Communications

As soon as is practicable and ideally within 1 working day following notification:

• for new cases notify the State/Territory Communicable Diseases Branch (CDB) of the case's age, sex, date of onset, vaccination history, laboratory result status, occupation, travel history, likely source of infection, high risk settings where people were exposed, and public health action taken.
• Notify each new case in an ongoing outbreak to the CDB, to provide regular updates on progress to identify when further escalation is warranted, and to confirm when any outbreak is deemed to be over.
• The State/Territory CDB should report summary details of cases and outbreaks to CDNA during regular teleconferences. For outbreaks or cases with the potential to involve multiple jurisdictions, the State/Territory CDB should notify the relevant jurisdictional members either directly or via the CDNA secretariat, as appropriate
• For outbreaks with the potential to involve multiple jurisdictions, the State/Territory CDB should liaise with the chair of CDNA and determine whether an urgent teleconference should be convened.
• Where there are cases or contacts among people from overseas, the State/Territory CDB should notify the Commonwealth Department of Health's National Incident Room (via Health Ops) who will comply with the International Health Regulations reporting requirements.

7. Case definition

Case definitions can be found on the Department of Health's website.

The current measles case definition is:

Reporting

Both confirmed cases and probable cases should be notified.

Confirmed case

A confirmed case requires either:

• laboratory definitive evidence, or
• clinical evidence and epidemiological evidence.*

Laboratory definitive evidence

At least one of the following:

• Isolation of measles virus*, or
• Detection of measles virus by nucleic acid testing*, or
• Detection of measles virus antigen*, or
• IgG seroconversion or a significant increase in antibody level, such as a fourfold or greater rise in titre to measles virus except if the case has received a measles-containing vaccine eight days to eight weeks prior to convalescent specimen collection. (Note: paired sera must be tested in parallel).

*Where measles vaccine has been given in the three weeks prior to illness onset and wild-type virus is not detected, or unable to be detected, a case may be considered “confirmed” only if the criteria for clinical and epidemiological evidence can also be met, suggesting wild-type infection. Vaccine-associated measles illness (genotype A) is not notifiable, but rather should be reported as an adverse event following immunisation.

Clinical evidence

An illness characterised by all of the following:

• A generalised maculopapular rash lasting three or more days, and
• Fever (at least 38°C if measured) at the time of rash onset, and
• Cough, or coryza or conjunctivitis or Koplik spots.

Epidemiological evidence

An epidemiological link is established when there is:

• Contact between two people involving a plausible mode of transmission at a time when:
  • one of them is likely to be infectious (from 24 hours before onset of prodromal symptoms or four days before rash onset to four days after rash onset), and
  • the other has an illness that starts within seven to 18 days after this contact, and
• At least one case in the chain of epidemiologically linked cases (which may involve many cases) has laboratory confirmed measles.

Probable case

A probable case requires laboratory suggestive evidence and clinical evidence.

Laboratory suggestive evidence

Detection of measles specific IgM antibody; except

• If ruled out by more specific measles IgM serology testing at a jurisdictional public health laboratory, or
• If the case has received a measles-containing vaccine eight days to eight weeks before testing.

Clinical evidence

As with confirmed case.

Suspected case

A suspected case requires clinical evidence only.

Clinical evidence

Same as for confirmed case.

8. Laboratory testing

Definitive laboratory evidence should be sought for all suspected measles cases. The results should be interpreted in the context of the clinical and epidemiological findings, and vaccination history. Depending on the context, tests for other clinically plausible infectious causes of fever/rash illnesses (such as rubella, roseola, dengue fever and other arboviral infections, scarlet fever, human parvovirus (B19) infection, enterovirus, adenovirus, HIV, Kawasaki disease) should usually be undertaken at the same time as measles tests when investigating suspected cases. If measles is the working diagnosis, make arrangements wherever possible for diagnostic specimens to be collected from suspected cases isolated at home, rather than having them visit a clinic or specimen collection centre where there is a risk of transmission to others.

Testing guidelines

Public Health Laboratory Network (PHLN) provides information on the laboratory diagnoses of measles.

The recommended laboratory tests for measles diagnosis and their timelines are outlined in Table 1

Table 1: Recommended laboratory tests for measles diagnosis based on symptom onset

In an established outbreak, laboratory confirmation by isolation or measles antigen/genome detection should be obtained on at least two cases, but may not be necessary for cases who meet the clinical case definition and have a clear epidemiological link to a confirmed case. Serological confirmation is encouraged for these cases.

The reliability of serological and direct detection tests for asymptomatic contacts is unknown. Testing of asymptomatic contacts is not recommended. However there are limited circumstances where it may be appropriate to test exposed contacts to determine if they are immune, such as healthcare workers for whom it is too late for post-exposure prophylaxis to be effective, and who need to be excluded from patient-care duties unless they have demonstrable immunity to measles, and pregnant women for whom normal human immunoglobulin (NHIg) may be recommended if susceptible.

Measles Nucleic Acid Testing (PCR)

• Laboratory confirmation by nucleic acid testing (NAT) or virus isolation is preferred for all sporadic cases and at least one case in each chain of measles transmission.
• Respiratory specimens and first catch urine (collected up to 3 weeks after onset of the rash) or EDTA blood or sera collected early in the illness can be referred to an approved reference laboratory for measles PCR on an urgent basis in sporadic suspected cases, and in at least one case in every chain of transmission.
• The PHU should facilitate communication with and between the laboratories involved concerning collection of suitable specimens and transport arrangements. Where appropriate, and in consultation with the patient's doctor, arrange for a home visiting pathology service to expedite specimen collection for suspected cases.
• Nasopharyngeal aspirates or nasopharyngeal swabs are the preferred sample for nucleic acid detection by PCR. Throat swabs or nasal washes are also suitable for PCR. A dry sterile swab of the nasal passage combined with a similar swab from the back of the throat is the recommended specimen for detection of viral nucleic acid (PCR). Swabs should be flocked, cotton, rayon, or dacron-tipped, plastic-coated or aluminium shafted swabs. They should be placed into viral transport medium. Samples should be stored and transported at 4°C. If arrival at the testing laboratory will be delayed more than 72 hours then, if possible samples should be frozen at -70°C and transported on dry ice. Do not freeze at -20°C.
• Early catch urine samples should be stored and transported at 4°C. If arrival at the testing laboratory will be delayed more than 72 hours then, if possible samples should be frozen at -70°C and transported on dry ice. Do not freeze at -20°C.
• EDTA blood for PCR should be stored and transported at room temperature.

Measles serology

• A 5 mL tube of clotted blood is the preferred specimen for serological testing.
• An IgM response will be present in approximately 75% of measles cases 3 days after rash onset, rising to approach 100% after 7 days. A measles IgG antibody test should preferably be performed together with the IgM assay to aid interpretation.
• Measles-specific IgM is a sensitive and specific marker of recent measles infection, but can also be detected for 1 to 2 months following immunisation.
• There is poor negative predictive value of an IgM result early in the illness. A negative result does not rule out a diagnosis of measles if the sample was taken earlier than 72 hours after onset of the rash. When no measles IgM or IgG antibody is detected in a sample collected within 3 days of rash onset from a suspected case of measles, repeat testing is recommended after 7 days.
• Where there is a suspected false negative or false positive IgM result NAT testing is recommended. Repeating the IgM and/or testing for measles specific IgG seroconversion by EIA on paired sera collected 10-14 days apart is helpful.
• For sporadic cases, measles serology results should be confirmed, ideally by a reference laboratory using the Dade Behring assay.
• Testing paired sera using the complement fixation test (which expresses results in titres) may also be helpful, especially in cases with a history of measles vaccination.
• Note that persons with waning or partial immunity - for instance those who may have received only one dose of measles containing vaccine in the past - may experience an attenuated measles infection with a milder clinical course than is normally seen, and serology may be misleading with false negative IgM and positive IgG. It is important that public health management of such cases is based on the likelihood of infection, and that they have nasopharyngeal swabs, EDTA blood specimens and/or urine specimens submitted for NAT testing.

Measles culture

• Measles virus may be identified by cell culture from blood, conjunctival swab, throat swab, nasopharyngeal swab or aspirate if taken within 5 days of the onset of the rash, and from urine for up to 10 days after the onset of rash.
• Nasopharyngeal aspirates or nasopharyngeal swabs are the preferred sample for antigen detection by culture.
• Throat swabs are also suitable for culture.
• The swabs should be placed immediately after collection into viral transport medium, and all these samples should be transported at 4°C.

Measles immunofluorescence

• Antigen testing by immunofluorescence may also be performed on respiratory or urine samples collected during the prodrome or in the first few days after rash onset. Any isolate or immunofluorescence positive material should be referred to the Victorian Infectious Diseases Reference Laboratory (VIDRL) for genotyping. These samples may allow epidemiological identification of a measles importation source.
• Nasopharyngeal aspirates or nasopharyngeal swabs are the preferred sample for antigen detection by immunofluorescence.
• Throat swabs may not be sufficiently sensitive for immunofluorescence.
• The swabs should be placed immediately after collection into viral transport medium, and all these samples should be transported at 4°C.

Measles genotyping

• It is important that NAT or immunofluorescence positive material or a viral isolate from all sporadic cases (including those that cannot be clearly linked to another case during an outbreak) and at least one case from any documented chain of transmission should be sent for measles virus genotyping. This assists in confirming the source of measles importation and confirms that endemic measles transmission has not been re-established in Australia.
• Where a State/Territory does not have the facility for the WHO accredited measles virus genotyping, samples may be sent to Victorian Infectious Diseases Reference Laboratory (VIDRL).
• Genotyping data from VIDRL, FSS (Qld) and SA Path are loaded directly onto the Measles Nucleotide Surveillance (MeaNS) database for the WHO Measles Laboratory Network. MeaNS is web accessible and searchable. Genotyping data are used in the ongoing verification of measles elimination within Australia.

The effect of recent vaccination

• Vaccine-induced "measles" is a modified form of measles that may occur 5-12 days after measles vaccination. It is not transmissible and should NOT be classified as measles.
• In contacts who are given post-exposure MMR vaccination, a fever/rash illness could represent a real infection following from the initial exposure, or a post-vaccination infection. NAT/culture testing and virus genotyping should be carried out to resolve the cause of the apparent infection, as the genotype for the vaccine strain is distinct from wild virus strain. NAT detection may be possible for some time after the rash disappears.
• Where measles vaccination has been given in the 3 weeks prior to illness onset and wild-type virus was not detected, or unable to be detected, a case may be considered confirmed based on a considered review of clinical features and epidemiological and laboratory evidence.
• Serology is of no use in diagnosis of suspected measles in persons who received a measles-containing vaccine 8 days to 8 weeks before testing.

9. Case investigation

Response times

Investigation

On same day of notification of a suspected, probable or confirmed case, begin follow-up investigation using the Measles Investigation Form.

Response procedure

Case investigation

The response to a notification will normally be carried out in collaboration with the treating doctor. If possible, inform the treating doctor that you will be contacting the patient or their carer(s). However, where this cannot happen in a timely fashion, follow-up should proceed.

Regardless of who does the follow-up, PHU staff should ensure that action has been taken to:

• Interview the case or relevant caregiver, wherever possible. Suspected cases should usually be managed as though they are confirmed cases while awaiting laboratory results. Confirm the onset date and symptoms of the illness.
• Where the case is a resident of another jurisdiction in Australia, cross-border notification procedures should be followed, and coordination of public health follow-up, including interviewing the case, made between the involved jurisdictions.
• Review vaccination status of the case, including the dates of vaccination.
• Confirm results of relevant pathology tests, or that appropriate tests have been ordered and specimen referral and testing is proceeding as a matter of priority. Where results are required urgently to determine the public health response, arrange for the laboratory to phone the appropriate public health officer, and/or follow-up actively with the laboratory.
• Identify the likely exposure window and infectious period.
• Identify the likely source—for instance, check travel history (overseas or interstate) or contact with a confirmed case during the case's infectious period or recent contact with persons with fever/rash illness consistent with measles.
• Determine carefully a chronological history of potentially exposed contact persons to the extent possible, as well as places visited while the case was likely to have been infectious. This may include a wide range of locations, such as child-care centres, schools, work-places, public transport, shops, cinemas, medical clinics, hospital EDs and pathology collection centres.
• Review case management, including appropriate isolation and infection control if admitted to a hospital.

Exposure Investigation

PHUs should thoroughly investigate possible exposures while interviewing the case to determine whether infection was acquired overseas, or linked in some way to a known imported or locally acquired case.

Case treatment

Supportive only.

Education

The case or relevant caregiver should be informed and given written advice about the nature of the infection including the mode of transmission and the infectious period, with dates specific to the patient. A fact sheet is useful for this purpose (see Appendix 3).

Isolation and restriction

• Exclude suspected, probable and confirmed cases from work, school, early childhood education and care services.
• Advise them to stay in isolation, and specifically advise against interaction with susceptible people, until 4 days after the onset of the rash. When a case is isolated at home, visitors should be discouraged while the case is infectious.
• Consider making a daily phone call to monitor compliance with isolation, and to encourage seeking medical attention, at home, if clinically indicated.
• Suspected cases seen in general practice or hospital emergency departments should be identified at the reception or triage desk, be fitted with a mask and immediately diverted away from waiting areas to a separate room (when in a hospital setting preferably with negative pressure ventilation) where they can be assessed by staff using airborne precautions.^[6]
• Hospitalised measles cases should be kept in respiratory isolation (and preferably in a negative pressure room) until 4 days after the onset of the rash. If a negative pressure room is not available, the case should be in single room with the door closed. Only healthcare workers who have documented immunity should care for these patients. Airborne precautions should be maintained within the patient’s room^[6] and the patient should use a mask when being transported.
• Suspected cases should be managed as though they are probable or confirmed cases whilst awaiting laboratory results.

Active case finding

The occurrence of a measles case may require the following response:

• Alert local doctors, emergency departments and laboratories in the area(s) where the measles case may have acquired or spread the infection, to the possibility of further cases. Encourage doctors, hospitals and laboratories to notify suspected and confirmed cases to the PHU promptly.
• Consider the need for a media alert to assist in case-finding. This decision will depend on factors such as the travel history of a single case and any evidence of spread, and should be decided in consultation with the State/Territory CDB.

10. Control of environment

None routinely required.

11. Contact management

Identification of contacts

The objective of contact tracing is to identify all potential contacts and then to target those at particular risk of disease for intervention. Identifying contacts of measles cases is required to determine who has been potentially exposed to an infectious case, to assess their susceptibility to infection and to provide advice and implement post-exposure prophylaxis, where appropriate.

Contact definition

Since measles is primarily transmitted by air-borne means, a contact is defined as anyone who has or may have shared the same air-space (enclosed area) for any length of time with an infectious case. Contact tracing should aim to identify those most susceptible to measles or at greater risk from infection, including infants, immunocompromised people and pregnant women.

In general, contacts may be prioritised in the following order, recognising that it may not be feasible for the PHU to identify and arrange post-exposure prophylaxis for all susceptible contacts, given the constraints of time, resources and logistics:

• The household, and other settings where people share communal facilities (for example, in a hospital, boarding school or military barracks)
• Early childhood education and care services, school or other educational settings where people share a classroom with the case
• People who shared a waiting area at the same time as the case (for example, patients in a healthcare facility’s waiting room and any people accompanying these patients) and people who used the waiting area or who were seen in the same consulting room for up to 30 minutes after the case left. The latter period is based on the recognition that normal room ventilation systems ensure that levels of airborne viruses and virus survival diminish rapidly.
• Work settings where work colleagues have shared the same work area or communal facilities at the same time as a case.

The following settings will generally not require individual contact tracing, and group level communication or a media release may be sufficient:

• Others who attend or work in the same educational institution as the case, and may have spent time in the vicinity of the case, but do not share a classroom (for example, use of common facilities such as a lecture theatre block at a high school or college)
• Passengers on an aeroplane (see Section 12, Special Situations)
• Others who may have been present in the general area where the case was known to be (for example, cinemas, shopping centres, airport transit lounges, trains and restaurants)

Contacts are considered susceptible to measles if they cannot provide evidence of immunity to measles. A person can be considered to have acceptable evidence of immunity to measles if they meet one of the following criteria, noting that more stringent levels of evidence should be obtained for contacts at higher risk of disease or severity:

• Persons born before 1966 (unless serological evidence is already available and indicates otherwise)
• Persons born during or since 1966 who have documented evidence (including GP confirmation, ACIR or personal record) of receiving 2 doses of a measles-containing vaccine, with both doses given at ≥ 12 months of age and at least 4 weeks apart (unless serological evidence indicates otherwise)
• Documented evidence of immunity (i.e. a detectable measles-specific IgG)
• Documented laboratory definitive evidence of prior measles.

Post-exposure prophylaxis

Refer to Table 2 and Table 3 for detailed guidelines for measles post-exposure prophylaxis.

Consideration should be given to providing susceptible contacts with either MMR vaccine or in some circumstances normal human globulin (NHIG), according to the following criteria and using Table 2 and Table 3:

• Time elapsed since exposure to an infectious case - where there has been ongoing exposure (such as with household contacts) the time since exposure should be calculated from the first contact during the infectious period
• Age
• Previous MMR vaccination history
• For infants from birth to 5 months, their mother’s history of measles infection or MMR vaccination before current pregnancy
• Immune competence.

In general it is not feasible to perform timely serology in contacts to determine immunity, as resulting delays in providing post-exposure prophylaxis increase the likelihood of treatment failure. It is safe to give MMR (or NHIG, as indicated) to individuals who are already immune. For infants <6 months of age (and exposed pregnant women) it may be possible to check maternal IgG levels in stored serum from recent antenatal testing, or collect a further specimen if time allows.

In settings with large numbers of individuals with uncertain vaccination histories and immunity

(e.g. in high schools, adult workplaces) it is reasonable to recommend prompt MMR vaccination, even if it is >72 hours after the exposure. In these circumstances, further cases of measles may occur (as someone may already be incubating the disease), but the liberal use of MMR should reduce the likelihood of ongoing transmission of the measles virus within these groups.

MMR is recommended as the first dose of measles-containing vaccine in children under 4 years of age, due to an increased risk of fever and related adverse events when MMRV is given as the first dose.^[5]

MMRV can be used for the second dose of measles-containing vaccine in children aged between 12 months and under 4 years of age, and as the first or second dose in children aged between 4 years and under 14 years of age. MMR—and not MMRV—should be used in persons aged 14 years or above.^[5]

Broad use of NHIG, such as in large numbers of healthy adults who have had casual contact (e.g. in a medical waiting room or normal workplace) between 72 hours and 6 days previously, and who are not able to provide evidence of documented past vaccination or immunity, is likely to be impractical and unnecessarily wasteful of NHIG and of staff resources.

NHIG should usually be reserved for contacts at higher risk of disease or severity of disease such as:

• Susceptible household contacts
• Immunocompromised individuals
• Pregnant women who cannot provide evidence of either immunisation or immunity
• Infants too young to be vaccinated and who are not likely to be protected by maternal antibodies (i.e. infants born to susceptible mothers; those aged 6–11 months if not timely for MMR).

NHIG may also be considered for use in school children exposed to a confirmed case, and may be used sparingly in exposed susceptible healthcare workers in situations where their exclusion from the workplace would affect service delivery significantly.

Note: People who receive NHIG for measles post-exposure prophylaxis will not be able to receive an MMR (or varicella-containing vaccine for at least 5 months (dependent on dose)^[5]). This may affect immunisation scheduling of children participating in the National Immunisation Program.

People who receive NHIG should be advised that they may still develop measles infection, however, signs, symptoms and time course of illness may be atypical.

Immunocompromised contacts

The assessment of the severity of immunocompromise is often best determined by consulting with the treating clinician, with guidance from an appropriate senior PHU staff member or director.

MMR is a live vaccine and is contraindicated in ‘severely immunocompromised’ people as defined in the 10th edition of the Australian Immunisation Handbook. See ‘Vaccination for Special Risk Groups’ section 3.3.3 ‘Use of live viral or live bacterial vaccines in immunocompromised persons’. Section 3.3.3 also includes advice on immunocompromised contacts who are unable to maintain previously acquired antibody levels.

Most contacts who are immunocompromised should be able to maintain adequate antibody from prior measles vaccination or infection. However, because immunocompromised people may have severe disease if they are infected with measles virus, urgent IgG antibody testing should be performed where possible to correctly determine the person’s immune status, especially if there is an uncertain history of past immunisation or measles infection. If IgG is detected, they should be regarded as immune. If IgG serology is negative, they should be offered NHIG if they are within 6 days (144 hours) of exposure to the case.

Education

• Advise susceptible contacts (or parents/guardians) of the risk of infection and counsel them to watch for signs or symptoms beginning 7 to 18 days after the first contact with an infectious case (or longer if the contact received NHIG). They should avoid contact with young children (under 12 months or unvaccinated), hospitals, pregnant women and immunocompromised people during this period.
• Advise that if symptoms consistent with measles develop, they should self-isolate and telephone the PHU; and that if they need medical attention they should arrange for a home visit or call ahead before visiting doctors’ rooms, hospital EDs or pathology services so as to avoid mixing with other people in waiting rooms.
• A sample script and ‘Measles: information for contacts’ fact sheets can be found in Appendices. Information should be provided to individuals in their own language where available.

Isolation and restriction

• Susceptible contacts in early childhood education and care services and primary schools^[1] should be excluded until 14 days ^[2] after the onset of the rash in the last case occurring at the facility or 18 days after the last contact with an infectious case to whom they were exposed outside the facility. However they may return if vaccinated within 3 days (72 hours) of first exposure to an infectious case or if they receive NHIG within 6 days (144 hours) following exposure.
  • If a child or staff member receives MMR more than 72 hours after exposure and hence requires exclusion, if the outbreak is ongoing they may return to the facility if they remain well and more than 18 days have elapsed since their last contact with a case.
  • Immunocompromised children or staff should be excluded (regardless of their measles vaccination status) until 14 days after the onset of the rash in the last case occurring at the facility. Exclusion is advised for their own safety, even if they receive NHIG.
• Adults in normal work situations or tertiary education facilities who are susceptible contacts do not always need to be excluded from work, education or social settings, depending on an assessment of their likelihood of developing measles and the likely consequences of infecting others. However, in these instances, they should be advised to isolate themselves from the time of onset of any prodromal symptoms consistent with measles, and to advise the PHU and seek medical assessment, as described under the Education section above. Exceptions may be necessary, and should be considered on merit in relation to the degree of exposure and the implications should the contact develop measles. For instance, it would be reasonable to exclude an exposed susceptible contact from returning to work in a remote mining community or on an oil rig or a ship for 18 days after last contact with a case of measles.
• Consider making a daily phone call to monitor compliance with quarantine, and to encourage seeking medical attention, at home, if clinically indicated.

Table 2: Post-exposure guidelines – within 3 days (72 hours) of first exposure to infectious case

*See discussion about immunocompromised contacts in section 11. Consult with treating clinician about interpretation of IgG results and use of NHIG.

Table 3: Post-exposure guidelines – from 3 days (72 hours) to within 6 days (144 hours) of first exposure to infectious case

*See discussion about immunocompromised contacts in section 11. Consult with treating clinician about interpretation of IgG results and use of NHIG.

Access to normal human immunoglobulin (NHIg) under the national blood arrangements

• NHIg may be supplied under the national blood arrangements for public health disease control activities, to treat susceptible contacts of an indicated infectious disease (hepatitis A, measles, poliomyelitis or rubella), where directed by the public health units in each state and territory.
• To order NHIg for public health disease post-exposure prophylaxis, follow the instructions at the National Blood Authority website, including completing and lodging a Normal human immunoglobulin (NHIg) order form.
• In addition, NSW Health has authorised the pre-positioning of NHIg in certain rural areas (including John Hunter, Bathurst, Orange, Dubbo, Port Macquarie, Coffs Harbour, Lismore, Tamworth, Armidale, Wagga Wagga, Goulburn, Bega, Griffith, and Broken Hill) to facilitate urgent access. The ARCBS is still charged with authorising access to that stock – this is because it may be more efficient to deliver short-expiry stock from elsewhere (generally the stock pre-positioned will be long-expiry stock).

12. Special situations

Cases among children or staff at schools or in early childhood education and care service

• In addition to routine case and contact management, for sporadic cases with an unknown source ask about possible cases occurring among attendees or employees within the 3 weeks prior to onset in the known case. Parents and staff should be provided with information about the disease and its prevention. Written information such as a fact sheet is recommended, but an information meeting for parents may also be useful (see Appendices for sample letters to parents).
• Consider holding an immunisation clinic at the facility. Vaccination of all susceptible contacts aged 6 months of age or over should be recommended, even if it may be too late for vaccine to be protective in relation to the exposure and the child/worker requires exclusion.
• Monitor for occurrence of further cases for 18 days after the last attendance by an infectious case. All suspected cases should be investigated and measures taken to minimise or eliminate secondary transmission from these cases.
• If no further cases have occurred by 18 days after the last attendance by an infectious case then it is generally reasonable to conclude that there has been no further transmission in the facility and the outbreak is over.

Cases among staff or patients in a healthcare facility

For suspected, probable or confirmed cases among staff or patients in a healthcare facility, practice management, infection control and/or occupational health staff from the facility should consult immediately with the local PHU to institute a management plan appropriate to that facility. PHUs should liaise with and assist general practices and similar facilities (e.g. private allied health clinics) in follow-up of patients exposed in waiting areas and consultation rooms in these settings.

Whilst the PHUs coordinate the overall contact management strategy, PHUs should liaise with staff health or infection control teams (where they exist). Hospitals should take primary responsibility for implementing prevention and control measures for their facility, including identification and follow-up of potentially exposed inpatients, staff and discharged patients. The latter includes inpatients, outpatients and those who attended the emergency department, and those who accompanied them, as appropriate. Depending on respective work-loads and resources, PHUs may be able to assist hospitals with follow-up of patients discharged to the community.

See Appendices for procedures and principles to include in management plans for healthcare facilities

Cases among travellers on aeroplanes

Previous guidelines on the follow-up of measles cases on aeroplanes recommended contact tracing of passengers seated within 2 rows of the case. However, experience shows that most secondary cases resulting from transmission during aeroplane travel are seated outside this range of seats.^[7-10] A recent review found that secondary infections occurred in 14% of flights that carried infectious measles cases notified in Australia over a 4.5 year period. Given delays in diagnosis and notification of the index case and the further time it can take to obtain passenger manifests and determine telephone/email contact information for people seated within a range of adjacent seating rows, it may not be feasible to locate potentially susceptible exposed passengers in sufficient time for post-exposure prophylaxis to be protective.^[10] Such individual level contact tracing of airline passenger contacts is also resource intensive.

Based on current evidence, direct contact tracing of passengers based on seating proximity should not be undertaken routinely.^[10] Rather, PHUs should consider less resource-intensive and possibly more timely strategies that reach more passengers, including, in collaboration with the airline:

• General media alerts
• Email or SMS messaging, if airlines can provide details or undertake messaging on behalf of the PHU, using a provided script.

Circumstances in which individual contact tracing for aeroplane flights might be justified include those where:

• Diagnosis and notification have been early
• Flight manifests are readily available and passenger contact information can be provided promptly
• There have been multiple infectious cases, especially children, on a flight.^[10]

PHUs/CDBs should continue to promote and encourage pre-departure measles vaccination to travellers who do not have a documented history of measles vaccination and raise awareness among medical practitioners of the need to consider the diagnosis of measles in overseas visitors and returning travellers who have clinically compatible illnesses with fever and rash.

Local transmission of measles

Where transmission of measles is identified within Australia, use of epidemiological data will be important to inform awareness raising in the relevant area to alert local doctors, hospitals, laboratories and the general public. This may encompass use of local print and electronic media, and fax or email distribution lists for medical practitioners, hospitals and pathology laboratories. In addition, identification of population groups at greater risk will be important for targeting prevention and control strategies.

PHUs should liaise with GPs and hospital EDs to promote early identification, isolation and appropriate testing of suspected cases, and their notification to PHUs.

13. References

1. Guidelines on verification of measles elimination in the western pacific region.
2. DL Heymann, editor. Control of communicable diseases manual. 19th Edition. Baltimore, United States of America; 2008.
3. Centers for Disease Control and Prevention. Epidemiology and Prevention of Vaccine- Preventable Diseases, The Pink Book.12th ed. National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention; 2011.
4. Gidding HF, Gilbert GL. Measles immunity in young Australian adults. Commun Dis Intell Q Rep. 2001 Aug;25(3):133–6.
5. Australian Technical Advisory Group on Immunisation, Australian Government Department of Health and Ageing. The Australian Immunisation Handbook 10th Edition. Canberra: Australian Government; 2013.
6. National Health and Medical Research Council. Australian Guidelines for the Prevention and Control of Infection in Healthcare.
7. Coleman KP, Markey PG. Measles transmission in immunized and partially immunized air travellers. Epidemiol Infect. 2010 Jul;138(7):1012–5.
8. De Barros FR, Danovaro-Holliday MC, Toscano C, Segatto TC, Vicari A, Luna E. Measles transmission during commercial air travel in Brazil. JClin Virol. 2006 Jul;36(3):235–6.
9. Beard F, Franklin L, Donohue S, Moran R, Lambert S, Maloney M, et al. Contact tracing of in- flight measles exposures: lessons from an outbreak investigation and case series, Australia, 2010. West PacSurveill Response J. 2011 Jul;2(3):25–33.
10. Hoad VC, O’Connor BA, Langley AJ, Dowse GK. Risk of measles transmission on aeroplanes: Australian experience 2007-2011. Med J Aust. 2013 Apr 1;198(6):320–3.

14. Appendices

• Appendix 1 - PHU Checklist [PDF]
• Appendix 2 - Sample Letters for Child Care, Primary and High Schools [DOC]
• Appendix 3 - Sample Script: Waiting Room Contacts [DOC]
  
• Appendix 4 - Measles Investigation Form [PDF]
• Appendix 5 - Measles Fact sheet
• Appendix 6 - Measles Information for Contacts - Assessment by Healthcare Professional and Information [PDF]
  
• Appendix 7 - Measles Information for Contacts - Information Only [PDF]​
  
• Appendix 7 - Management Plan for Healthcare Facilities [PDF]
  
• Appendix 8 - Enhanced Measles Triage for Emergency Departments