Measles

In 2017, Aotearoa New Zealand was verified by the World Health Organization as having eliminated endemic measles. It has maintained elimination since then. This means that there has not been sustained transmission of measles for longer than a year in New Zealand since 2014. However, measles is often imported into New Zealand following international travel.

New Zealand has continued to experience outbreaks of measles in recent decades. In the 2019 outbreak, more than 2000 people were infected with measles. The majority of cases were in Auckland and Canterbury, and the virus spread across many other parts of New Zealand and into neighbouring Pacific countries. More recently, New Zealand experienced more contained outbreaks in February and May 2023, with both located in Auckland.

Reoccurring measles outbreaks are due to historically low immunisation rates and therefore insufficient levels of immunity across the population to prevent community transmission. Prevention of measles outbreaks relies on improving coverage with measles-mumps-rubella (MMR) vaccination.

More detailed epidemiological information is available on the Institute of Environmental Science and Research (ESR) surveillance website.

Confirmed: A person who has a clinically compatible illness AND has laboratory definitive evidence OR has an epidemiological link to a confirmed case.

Probable: A person who has a clinically compatible illness where there is a high index of suspicion* AND has laboratory suggestive evidence OR laboratory testing is inconclusive or cannot be performed.

*A high index of suspicion includes all the following.

• Is susceptible to measles (not immune)
• Has a classical measles presentation.
• Has been in an area with known measles cases during the incubation period. 

Under investigation: A person who has been notified to the medical officer of health, but information is not yet available to classify it further.

Not a case: A person who has been investigated and subsequently found not to meet the case definition.

 A clinically compatible illness is characterised by all of the following.

• Cough and/or coryza and/or conjunctivitis and/or Koplik’s spots present at the time of rash onset.
• Fever (at least 38ºC if measured) present at the time of rash onset.
• Generalised maculopapular rash, starting on the head and neck then spreading downwards and outwards and fading.

Note: Some people may present with an illness that does not meet all the above criteria (e.g. if they have had previous vaccination or infection). These cases require laboratory definitive evidence to be classified as a confirmed case.

An epidemiological link is established when there is contact between two people with a plausible mode of transmission at a time when one of them is likely to be infectious and the other has onset of illness within the incubation period.

Laboratory definitive evidence

• Detection of measles virus by polymerase chain reaction testing. If vaccine strain is suspected, this must be excluded (see laboratory testing guidelines).

Laboratory suggestive evidence

• Confirmation of IgG seroconversion between paired sera tested in parallel or IgM detection in an unvaccinated person.

1. To confirm or exclude a diagnosis of measles in a suspected case.
2. To exclude vaccine strain virus in a confirmed case who has recently been vaccinated (genotyping or whole genome sequencing).
3. To determine measles immune status in a contact.
4. To track transmission pathways during a measles outbreak (whole genome sequencing).

Health practitioners should contact the local medical officer of health on suspicion of measles during the initial assessment of the person. The medical officer of health or other public health service clinical staff will discuss urgent cases with the on-call clinical microbiologist, where there is a high index of suspicion for measles, so that laboratory staff are aware of the urgency and can prioritise the sample for prompt processing. The clinical microbiologist is the point of contact with the laboratory.

A sample for a suspected case with a high index of suspicion requires urgent processing and should be marked ‘Urgent Public Health’.

Polymerase chain reaction (PCR) testing is the primary diagnostic tool. Laboratory confirmation requires a PCR positive result for measles. Refer to Laboratory criteria (laboratory definitive evidence and laboratory suggestive evidence) for confirmed and probable case interpretations.

Measles polymerase chain reaction (PCR) (nucleic acid amplification test)

Measles PCR on a nasopharyngeal sample is the preferred test. Measles virus is detectable from 3 days before rash onset to 7-14 days after rash onset. The routine measles PCR test does not distinguish between wild type and vaccine strain. This is done by vaccine-strain-specific genotyping. 

PCR tests have the highest diagnostic sensitivity when samples are collected at first assessment of a suspected case (maximum sensitivity is within 3 days of rash onset, but reasonable sensitivity is observed up to 7 days after rash onset).

Nasopharyngeal or oropharyngeal samples have the highest yield particularly in the 7 days after rash onset. Urine testing can be useful for those presenting after this time but should not be used in place of a nasopharyngeal or oropharyngeal swab. Discussion with a clinical microbiologist is advised if testing more than 7 days after rash onset.

Serology

Serology is primarily used to determine the immunity status of contacts. However, it can be used for diagnostic purposes where it could be considered laboratory suggestive evidence for confirmed measles infection.

The request form must state which investigation is required, immune status (IgG) or query infection (IgG and IgM). Full clinical details, including date of rash onset, will ensure the correct tests are performed. Refer to the table above for sample requirements.

Serology (Immunoglobulin IgM and IgG paired testing) to determine acute infection

The use of serology in the investigation of a suspected measles case is only recommended where PCR testing is not possible AND it is requested by a medical officer of health after discussion with a clinical microbiologist.

IgM and IgG paired serology for an acute infection is often unreliable, particularly in previously vaccinated people or due to cross-reactions from other viral infections.

Recent vaccination can result in an IgM response, and previously vaccinated but infected people may not develop an IgM response. IgM serology confirmed by the laboratory may occasionally help with diagnosis in late presentations. Any positive IgM result should be discussed with a clinical microbiologist.

Serology will not distinguish between wild type and vaccine strain measles.

Measles IgG detected without IgM within 1–2 days of a rash onset strongly suggests prior immunity and that the rash is more likely due to causes other than measles. The IgG results also offer limited value to inform public health actions given the second sample is required 2 weeks after the initial blood serology test.

Serology (Immunoglobulin G IgG) to determine immune status 

Note: Paired IgG serology is not generally recommended for diagnosis of measles. Testing must be discussed with the clinical microbiologist.

Serology is most useful for confirming immunity in people whose vaccination history is uncertain, although commercial tests do not detect all vaccine-induced immunity. See contact management section for guidance on when to do serology testing in contacts.

Vaccine-strain-specific genotyping

Vaccine-strain-specific genotyping is used to determine if a positive measles PCR result is due to recent vaccination.

Vaccine-strain-specific genotyping is automatically done by diagnostic laboratories on all primary cases of positive measles PCR samples (reflex tested) during the ‘stamp it out’ phase of measles management. 

All requests for measles PCR tests should have the person’s recent vaccination status and vaccine date included on the request form. Testing more than 90 days after vaccination is not recommended and should only be requested after discussion between the medical officer of health and the clinical microbiologist.

The presence of vaccine strain measles does not rule out potential co-infection with wild type strain. These cases should be discussed with a clinical microbiologist.

Occasionally, a vaccinated person with no known exposure to the measles virus can return a positive PCR result many months after vaccination due to vaccine strain fragments being detected. Vaccine-strain-specific PCR is indicated in these situations.

Whole genome sequencing

Whole genome sequencing is used for epidemiology and outbreak investigation as it allows genetic characterisation of the whole virus. Whole genome sequencing can be done on measles positive PCR test samples at the National Measles and Rubella Reference Laboratory at Canterbury Health Laboratories.

Whole genome sequencing should be done as soon as possible for all:

• new importations
• index cases and the first 5-10 cases of an outbreak/cluster. If the outbreak continues, then a strategy for ongoing sequencing of the outbreak should be developed.
• sporadic cases that are not epidemiologically linked to other genotyped cases or clusters
• samples requested by the medical officer of health investigating the outbreak.

About 10 days, but may be 7–18 days, from exposure to onset of fever, and about 14 days, but may be 7–21 days, from exposure to the onset of rash. The incubation period may be longer in those given immunoglobulin after exposure.

Airborne spread or by direct contact with nasal or throat secretions of cases. The measles virus has a short survival time (less than 2 hours) and is rapidly inactivated by heat, sunlight and pH extremes. Both ventilation and masking are effective at reducing (but not necessarily preventing) transmission of airborne diseases.

For public health purposes, the case is considered infectious from 4 days before appearance of rash to 4 full days after onset of rash (counting the day of rash onset as day 0), ie, this is a total of 9 days.

Attending health practitioners or laboratories must immediately notify the local medical officer of health of suspected cases. Notification from health practitioners should not await confirmation.

See Appendix 5: Escalation pathways for more information

Wherever possible, all relevant clinical and demographic information on the suspected case should be collected within one day.

Obtain a history of vaccination, immunodeficiency, contact with a probable or confirmed case and travel.

In consultation with the attending health practitioner, obtain laboratory confirmation where possible and necessary. Testing may not be necessary or appropriate for cases with an epidemiological link to a confirmed case in outbreak situations.

Isolate (ie, stay home unless seeking health care) for at least four days after the appearance of the rash. If seeking health care call ahead to inform that they are infectious with measles.

In health care facilities, airborne precautions should be taken until four days after the appearance of the rash.

Vitamin A treatment can reduce the risk of fatality and eye complications and should be considered particularly in cases of hospitalised children, and in cases with severe or complicated measles, immunodeficiency, malabsorption, malnutrition or documented vitamin A deficiency.

Advise the case and their caregivers of the nature of the infection and its mode of transmission. If other vaccinations are incomplete, recommend the case catches up once they are through the acute illness.

Public health services should alert doctors and laboratories in areas where the case may have acquired the infection or was infectious and should ask these doctors and laboratories to notify all cases to the public health service promptly. Part of the reason for this is that early prophylaxis given to susceptible contacts (see below) can reduce the risk of developing disease. Consider a media alert to assist in finding cases.

Measles contacts are defined by the extent of their exposure to a case and subcategorised by their immunity status. Contacts can also be defined by their risk of developing severe disease. 

Note: 

• Contact categorisation will not change in contacts who receive post-exposure immunoglobulin prophylaxis.
• Contacts who are immunosuppressed may still be susceptible to measles even if they are fully vaccinated or have had a previous measles infection.

Post-exposure prophylaxis — Starship

Classification of contacts by level of exposure

1. Close contact

A close contact is anyone who had any of the following exposures to a case during their infectious period. 

• Face-to-face contact of any duration. 
• Spent time (of any duration) in a confined indoor space at the same time as the case. 
• Spent time (of any duration) in a confined indoor space within 1 hour of the case leaving the space. 

A medical officer of health may use their discretion to apply a shorter or longer time for contact tracing purposes. For example, in a healthcare setting a shorter stand down period of 35 minutes is likely to be appropriate in airborne infection isolation rooms (AIIR) depending on the number of air changes per hour.  A 2-hour period may be appropriate for exposures in very small and poorly ventilated spaces because the measles virus can survive for up to 2 hours in the air.

• Interim infection prevention and control recommendations for measles in healthcare settings — Centre for Disease Control
• Post-exposure prophylaxis — Starship

Mask use by the case and/or contact may reduce the risk of a contact becoming infected with measles, however evidence for this is not established. In healthcare settings, staff members who use appropriate personal protective equipment, including an N95 or P2 mask, will not be considered close contacts.

Confined indoor spaces may include, but are not limited to, any of the following: classrooms, houses, healthcare settings (including inpatient rooms, waiting rooms, consultations rooms), workplaces and transport services (cars, buses, trains and domestic and international flights). 

Unidentifiable contacts who meet the close contact definition may be informed of their exposure through general communications, for example, locations of interest, social media, newsletter, and subsequently self-identify using Healthline or primary care.

Examples of unidentifiable close contacts are:

• individuals travelling on a bus where contact details are not available
• attendees of a small indoor event where there is no register of attendees.

2. Casual contact

Casual contacts are individuals who have been in a setting or at an event attended by an infectious measles case, where the level of exposure is either unlikely to meet the close contact definition or cannot be determined but there is possibility of transmission. Casual contacts may or may not be individually identifiable.

The casual contact category should not be used just because contacts cannot be identified. Unidentifiable contacts who meet the close contact definition should be defined accordingly and receive appropriate public health management if they self-identify.

If a risk assessment determines that all contacts at a setting have had sufficient exposure to put them at high risk of developing measles, for example, they travelled in a bus with an infectious case, they should be deemed close contacts.

They are considered a casual contact if any of the following apply.

• An infectious case attended a large event such as a sports stadium, where it is not possible to do an individual risk assessment to determine each contact’s level of exposure. For the attendees to be classified as casual contacts a medical officer of health must be satisfied that at least some of the individuals who attended the event could have had sufficient contact with the infectious measles case to put them at risk of infection. 
• An infectious case was present in a clearly defined area of a setting such as a school. The casual contact designation can be used for other individuals in that setting if a medical officer of health determines it is likely that other individuals at that setting, for example, the wider school campus had contact with the infectious case, for example, passing them in a corridor. This categorisation applies where the level of exposure outside the classroom setting cannot be determined, and any contacts are unable to be identified.

Examples of casual contacts are:

• attendees of a large event where it is not possible to identify individual contacts or ascertain their level of exposure, however, the medical officer of health has determined that there is a possibility of transmission
• school students and staff who have been in the school cafeteria where it is not possible to identify individual contacts but there is a possibility of transmission.

Classification of contacts by immune status 

1. Immune  

  A contact will be classified as immune if any of the following apply. 

• They were born before 1 January 1969. This is because prior to the measles vaccine being introduced to New Zealand in 1969, most people would have been exposed to measles and have developed immunity. A medical officer of health has discretion to apply a different date cut off for contacts born outside of New Zealand as measles vaccine was introduced earlier in some countries, for example, USA 1963. These contacts may require evidence of immunity.
• They have received two doses of a measles-containing vaccine, for example MMR, given at least four weeks apart and both were given after their first birthday.
• They received their second MMR within 72 hours of first exposure to an infectious case. 
• They have serology results confirming they are immune.
• They have evidence of a previous measles infection confirmed through testing, for example, PCR result.

2. Susceptible – partially vaccinated

A contact is classified as susceptible – partially vaccinated if they have had a single measles containing vaccine which was administered after the age of 12 months and at least 4 weeks prior to their exposure to a measles case. 

This includes infants aged 12-months to under 15-months who are age appropriately immunised with one dose of MMR.

A proportion of contacts who have only received one dose of MMR vaccine may be at risk of developing measles and spreading it to others. After a single dose of MMR vaccine 90 to 95% of people will be protected from measles (5 to 10% of people do not confer immunity from one dose, known as primary vaccine failure). After a second dose of MMR vaccine the number of people protected from measles increases to around 99%.

• Priorix - Immunisation Advisory Centre
• Log in to view Measles - American Academy of Pediatrics

3. Susceptible – non-immune  

A contact is classified as susceptible – non-immune if they do not meet the criteria for any other category.

This includes the following individuals. 

• Contacts who have not previously received any measles containing vaccine (MMR). 
• Contacts who have received one MMR vaccine, but it was administered prior to 12 months of age (MMR0) or less than 4 weeks prior to their exposure to a case. 
• Contacts with serology results indicating they are not immune (this also applies even if the result is equivocal or they have evidence of previous infection or vaccination). Contacts who received their MMR1 as post-exposure prophylaxis (this applies to the current exposure only).

Measles serology testing - Centre for Disease Control and Prevention 

Impact of immunosuppression on immunity to measles  

If a contact is immunosuppressed, they may require further assessment to determine their immune status as they may be susceptible to measles even if they have evidence of prior immunity.

Therefore, all immunosuppressed contacts should undergo a rapid assessment to determine their eligibility for post-exposure immunoglobulin prophylaxis. Casual contacts are not routinely assessed for immunosuppression and post-exposure prophylaxis (PEP) is not administered to them. Immunosuppressed or immunocompromised contacts may include:

• individuals receiving chemotherapy, radiotherapy, high dose steroids, immune modulating/immunosuppressive drugs, or biological therapies, for example, monoclonal antibodies.
• individuals with HIV, AIDS, or cancer
• individuals who have received an organ transplant, or a bone marrow transplant
• renal patients on dialysis and people with primary immunodeficiencies. For further information see resource links below.

Discussion with contact's clinical team is required.

Resources on renal patients on dialysis and people with primary immunodeficiencies:

• Measles, mumps and rubella vaccine Community Schedule - Pharmac
• Contraindications and special considerations: the green book, chapter 6 - UK Health Security Agency
• Immune Dysfunction and Risk of Infection in Chronic Kidney Disease - National Library of Medicine, PubMed
• Measles clinical guidance — Starship
• National measles guidance — UK Health Security Agency

Classifying contacts at high risk of severe disease 

Contacts at high risk of becoming very unwell with measles include:

• infants aged under 12 months
• immunocompromised people
• non-immune pregnant people and for 6 weeks post-partum
• non-immune children aged under 5 years.

These contacts may be eligible for post-exposure immunoglobulin prophylaxis (see Post exposure prophylaxis).

The section is currently being reviewed and updated.

This section is currently being reviewed and updated.

Contact investigation should focus on determining the following.

• The extent of the contact's exposure to the case (see definition of Close contact and Casual contact).
• The immune status of the contact.
• The quarantine period for the contact.
• Whether the contact is at risk of severe disease and should be considered for post exposure MMR or immunoglobulin prophylaxis.
• The feasibility of post exposure MMR prophylaxis.
• Whether a contact would have difficulties quarantining (see Serology testing of contacts below).

Assessing contact immunity 

The immune status of a close contact determines whether they are subcategorised as: 

• immune  
• susceptible – partially vaccinated
• susceptible – non-immune. 

In all circumstances, evidence of immune status is required. This means that contacts should be managed as susceptible - non-immune until evidence of immunity is provided. 

Serology testing of contacts 

During the ‘stamp it out’ phase of an outbreak, serology (IgG) testing should be used to determine immunity in close contacts if either their vaccination status is unknown, or they cannot obtain evidence of their immunity. This ensures that people who are immune can avoid unnecessary quarantine.

Where there is limited serology testing capacity, prioritisation of individuals for serology testing should be done in partnership with equity advisors.

When prioritising serology these groups should be considered when making decisions.

• Individuals at risk of severe disease, for whom post-exposure immunoglobulin prophylaxis may be recommended (noting this needs to be within 6 days of exposure).
• Contacts who would find quarantining difficult for economic, social, and/or mental health reasons. This aspect should always be considered for Māori, Pacific and low socio-economic peoples.
• Healthcare workers, and other workers performing critical functions, particularly if the service may not be able to continue to operate due to insufficient staff, for example, teachers.
• Individuals who have received a single MMR vaccine and would otherwise be restricted from attending high risk settings.
• Contacts who report being vaccinated overseas and are unable to provide adequate evidence of vaccination.

Close contacts with serology that is negative or equivocal will be managed as susceptible – non-immune (serology supersedes evidence of vaccination).

For this reason, partially vaccinated contacts should be advised of this before offering serology testing to exempt a contact from restriction requirements.

Monitoring and testing of symptomatic contacts 

All contacts (including casual contacts and immune contacts) should be advised to self-monitor for symptoms of measles for a total of 21 days from their last exposure to an infectious case even if they are not in quarantine (this is based on the full incubation period for measles). Contacts who receive post-exposure immunoglobulin prophylaxis should be advised to self-monitor for a total of 25 days from their last exposure (this is because immunoglobulin may extend the incubation period). If symptoms develop, they should be advised to stay home and contact public health, Healthline or their primary care provider for further advice. 

Casual contacts and immune close contacts 

• No active monitoring by public health services is required. 
• Advice to casual contacts may be provided as part of exposure event management or through public communications such as the locations of interest website or media statements.

Susceptible – partially vaccinated close contacts 

• Public health services should consider monitoring partially vaccinated close contacts for signs and symptoms consistent with measles for the duration of their restriction period. Monitoring frequency is expected to be less than for susceptible - non-immune contacts (see next section). 
• If a contact develops symptoms of measles they should be advised to stay home until measles is excluded. If testing is required, this should occur once the rash has developed, unless there are compelling reasons to do it earlier.
• A second dose of MMR should be offered as soon as possible after the period of restriction has ended. This second dose should be administered at least 4 weeks after the first dose. 

Susceptible – non-immune close contacts 

Public health services should actively monitor susceptible – non-immune contacts for the duration of their quarantine period.

Contacts with symptoms at the end of their quarantine period should be advised to stay home and monitoring should continue until measles has been excluded.

If testing is required, this should occur once the rash has developed, unless there are compelling reasons to do it earlier, in discussion with a clinical microbiologist.

Management of contacts differs according to their level of exposure to a case (close or casual contact) and their immune status. 

1. Casual contacts and immune close contacts 

No quarantine or restrictions are required.

2. Susceptible – partially vaccinated close contacts  

These contacts are not generally required to quarantine unless advised by a medical officer of health. For example, quarantine may be appropriate for some immunocompromised contacts who are partially vaccinated.

Although partially vaccinated contacts have a lower risk of becoming infected with measles than non-immune contacts, infection and transmission to others can occur, for more information refer to the Immunisation Handbook.

Measles - Immunisation handbook 

The following restrictions are recommended for the period from 7 days after their first exposure until 14 days after their last contact with the case. The ‘Measles quarantine calculator’ can be used to define the restriction period. 

Measles quarantine calculator — National Public Health Service Northern Region

• Do not attend high-risk close contact settings, such as early learning services or schools, where there is a high risk of transmission of measles. Restrictions may not be required if all individuals in these settings are vaccinated.
• Do not attend places such as hospitals, vaccination centres and other healthcare settings, where there could be people who are at high risk of severe disease.
• Stay away from people who are at risk of severe disease. For example, infants under 12 months, pregnant women, or women in the 6 weeks after delivery (unless you know they are fully vaccinated), and immunosuppressed people. 
• Contacts who require health care should be advised to phone ahead and say they are a measles close contact to enable appropriate infection control measures at a minimum the contact must wear a mask.
• A medical officer of health may recommend additional restrictions following a risk assessment.

3. Susceptible non-Immune close contacts  

These contacts should quarantine (stay home unless seeking necessary health care) from 7 days after their first exposure to an infectious case until 14 full days after their last exposure. This means quarantine will be for a minimum of 8 days.

If exposure extends over multiple days or involves exposure to several cases with different infectious periods, the quarantine period will be extended until 14 full days after their last exposure. Quarantine may also be extended (or additional restrictions recommended) if the contact is symptomatic at the end of the quarantine period and is being investigated as a possible case. 

Contacts who have received post-exposure immunoglobulin prophylaxis will have their quarantine period extended to 18 days (from 7 days after their first exposure to an infectious case until day 18 from their last exposure).

The ‘Measles quarantine calculator’ can be used to define the quarantine period. 

Measles quarantine calculator — National Public Health Service Northern Region

Contacts should monitor for symptoms for 21 days after their last exposure as this is the full incubation period for measles. If symptoms develop, they should remain at home and contact public health authorities or their healthcare provider.

Contacts who receive post-exposure immunoglobulin prophylaxis should monitor for symptoms for 25 days from their last exposure, as immunoglobulin may extend the incubation period.

Contacts who require health care should be advised to phone ahead and inform health care facility staff they are a measles close contact. This will enable these facilities to take action to prevent transmission. At a minimum, the contact must wear a surgical mask.

Contacts should be encouraged to get vaccinated as soon as possible after completing their period of quarantine or restriction. 

Stress the importance of two doses of measles vaccination for all children and encourage early childhood services to keep up-to-date immunisation records for all attending children.

Two doses of MMR vaccine are recommended for all children (without contraindications): the first at 12 months of age and the second at 15 months of age. Where dose/s have been delayed or missed, catch-up vaccination is recommended.

Catch-up vaccination is recommended for anyone born from 1 January 1969 who has missed doses of measles vaccine (or who cannot show they are immune).

New Zealand residents are eligible for a free primary course (two doses of MMR vaccine).

Depending on circumstances, such as during an outbreak or prior to international travel, a second MMR dose may be given 1 month after the first dose. During a generalised community outbreak, an extra dose (dose 0) may be offered to infants 6–12 months of age, but as effectiveness cannot be guaranteed, all children still need two further doses when they are over 12 months of age. This is because the seroconversion rate is lower when MMR is administered to an infant under 12 months of age.

Ensure that the attending health practitioner and laboratory collection rooms understand the importance of prompt isolation of a suspected case within their health care facility and the need to leave the consultation/examination room vacant for at least 1 hour after the suspected case has left it. Visits of cases and contacts (who may be entering the infectious period) to laboratory collection rooms should be planned ahead by telephone.

Ventilation and masking are effective at reducing transmission of airborne diseases.

Ensure complete case information is entered into NDMS (Notifiable Disease Management System).

If an outbreak occurs, contact 0800GETMOH - CD option, and outbreak liaison staff at ESR, and complete the Outbreak Report Form.

[1] Ministry of Health. (2020). Health Sector Response to the 2019 Measles Outbreaks. Wellington: Ministry of Health. Retrieved from https://www.health.govt.nz/publications/health-sector-response-to-the-2019-measles-outbreaks 

• Communicable Diseases Prevention and Control Unit. 2011. Measles. In The Blue Book: Guidelines for the control of infectious diseases (pp 127–130). Victoria: Public Health Branch, Department of Human Services, State Government of Victoria.
• Department of Health, Australia. 2019. Measles: CDNA National Guidelines for Public Health Units. Canberra: Department of Health.
• Gastanaduy PA, Redd SB, Clemmons NS, et al. 2019. Chapter 7: Measles. In Manual for the Surveillance of Vaccine-Preventable Diseases. 7.1–7.21. Atlanta: Centers for Disease Control and Prevention.
• Heymann D (ed). 2014. Control of Communicable Diseases Manual (20th edition). Washington: American Public Health Association.
• Hope K, Boyd R, Conaty S, et al. 2012. Measles transmission in health care waiting rooms: implications for public health response. Western Pacific Surveillance and Response 3(4) 33–38.
• Ministry of Health. 2020. Measles. In Immunisation Handbook. Wellington: Ministry of Health.
• Public Health England. 2019. National Measles Guidelines. London: Public Health England.
• Public Health Laboratory Network. 2009. Measles Laboratory Case Definition. Canberra: Department of Health and Ageing, Australian Government.
• WHO. 2009. Measles vaccines: WHO position paper. Weekly Epidemiological Record 84 (35): 349-360.
• WHO. 2005. Field guidelines for measles elimination. Manila: WHO Regional Office for the Western Pacific.