Measles

Key Messages

  • Measles is a highly communicable viral infection characterized by a prodromal fever, cough, conjunctivitis, coryza, Koplik’s spots, and a maculopapular rash that starts on the face and spreads down the body.
  • Although rare, measles cases continue to occur in Ontario and are usually travel-related. 
  • Measles is transmitted through close contact with the respiratory secretions of a case or through persistence of airborne nuclei in the air for up to 2 hours.
  • Measles-containing vaccine is part of Ontario's routine immunization schedule. Two-doses provide almost 100% protection and immunity is usually life-long.
  • Laboratory confirmation of measles must include two tests for viral detection by PCR (1. urine specimen and 2. throat or nasopharyngeal specimen) in addition to serology.
  • Suspected or confirmed cases of measles, whether clinically diagnosed or laboratory confirmed, must be reported to Ottawa Public Health immediately by calling: 613-580-2424 ext. 24224 during normal business hours of Monday to Friday, 8:30 a.m. – 4:30 p.m. After hours and holidays, please call 3-1-1 and ask for the Communicable Disease Manager on-call. Reporting a suspected measles case should not be delayed pending the return of confirmatory laboratory results.
Introduction
  • Suspected or confirmed cases of measles, whether clinically diagnosed or laboratory confirmed, must be reported to Ottawa Public Health immediately by calling: 613-580-2424 ext. 24224 during normal business hours of Monday to Friday, 8:30 a.m. – 4:30 p.m. After hours and holidays, please call 3-1-1 and ask for the Communicable Disease Manager on-call. Reporting a suspected measles case should not be delayed pending the return of confirmatory laboratory results.
  • Measles is a highly communicable viral infection. It is characterized by a prodromal fever, cough, conjunctivitis, coryza, and possibly Koplik’s spots (small white spots on the inside of the mouth and throat). The characteristic maculopapular rash starts on the face and spreads down the body and usually begins 3-7 days following the prodrome.
  • Measles requires airborne precautions to prevent spread. The measles virus is spread by airborne droplet nuclei, close personal contact, or direct contact with the nasal or throat secretions of infected persons, and can remain active and contagious in the air, depending on the number of air changes, for up to two hours.
  • See Public Health Ontario for more information on measles.
Local Epidemiology
  • As a result of immunization, measles was declared eliminated in Canada in 1998. Despite its elimination status, cases of measles continue to be seen in Ontario, including Ottawa, often from sick travellers returning from countries where measles has not been eliminated. 
  • Since 2014, Ottawa has seen 7 cases of measles. Ottawa Public Health does surveillance on measles as well as several other communicable diseases of public health importance. This surveillance is made public through infectious disease reports.
Signs and Symptoms
  • The first symptoms of measles usually begin 10-14 days (range 7-18 days) after contact with an infected individual and include the following:
    • A prodromal fever (≥38.3 oral),
    • Coryza,
    • Cough,
    • Conjunctivitis
    • Drowsiness,
    • Irritability,
    • Koplik's spots.
  • 3-7 days after the start of symptoms, a characteristic maculopapular rash appears on the face and spreads down the patient's body, lasting at least 3 days. CDC has several photos of children with measles that have different skin tones.
  • Complications of measles include:
    • Otitis media
    • Pneumonia
    • Blindness
    • Measles encephalitis (can result in permanent brain damage)
    • Subacute sclerosing panencephalitis (a disease of the central nervous system), a rare but fatal complication.
  • Those infected with measles are considered to be communicable from 4 days before  until 4 days after the onset of rash. 
  • Immunocompromised, pregnant, and malnourished individuals are particularly at risk of suffering from severe symptoms and complications of measles.
  • Immunity is usually lifelong after natural infection.
Laboratory Testing
  • Suspected or confirmed cases of measles, whether clinically diagnosed or laboratory confirmed, must be reported to Ottawa Public Health immediately by calling: 613-580-2424 ext. 24224 during normal business hours of Monday to Friday, 8:30 a.m. – 4:30 p.m. After hours and holidays, please call 3-1-1 and ask for the Communicable Disease Manager on-call. Reporting a suspected measles case should not be delayed pending the return of confirmatory laboratory results.
  • If the suspected measles case is under 18 years old, the physician or health care professional is asked to also page the Infectious Diseases physician on-call at CHEO (613-737-7600 ext. 0) to discuss the symptoms, determine if the child meets clinical criteria, and if testing at CHEO is required. The physician or health care professional is then asked to follow-up with the public health nurse to advise on outcome of consultation so the public health nurse can proceed accordingly. 
  • The laboratory testing below is also available on Ottawa Public Health’s webpage on measles laboratory testing or as a one-page PDF

Lab testing background

  • Lab testing for measles is not available in Ottawa.
  • Specimens are processed at the Public Health Ontario Laboratory in Toronto.
  • Please notify Ottawa Public Health prior to sending specimens as we may be able to expediate timely processing.

Laboratory requisition form must include the following:

  • Ordering physician or health care professional's name and telephone number
  • Specifying type of specimen (e.g. throat swab, nasopharyngeal swab, urine, serology)
  • For serology, mark as “Measles IgG and IgM"
  • Indicate acute/recent infection
  • Immunization history, exposure history and travel history outside Ottawa for 21 days prior to start of symptoms
  • Relevant signs, symptoms, and/or clinical history, and onset date
  • Reason for testing (i.e. "to diagnose measles" or "measles testing")

Laboratory testing

Must include two tests for viral detection by PCR (1. urine and 2. throat or nasopharyngeal swab) in addition to serology

Virus detection by PCR

Isolation of measles virus from two appropriate clinical specimens.

  1. Urine specimen: collect approximately 50 mL of clean catch urine in a screw top sterile container within 14 days after onset of rash.
  2. Throat or nasopharyngeal specimen: collected using a swab containing pink universal transport media within 7 days of the onset of rash.
    • A viral swab containing pink universal transport mediaThroat specimen: viral swab (Virus Culture Kit order #390081) containing pink universal transport media (i.e. the same swab used to test for HSV).
    • Nasopharyngeal specimen: nasopharyngeal swab (Virus Respiratory Kit order #390082) with pink universal transport media (i.e. same swab used to test for influenza or RSV).
    • *Note: Traditional red top throat swabs (e.g., Amies with or without charcoal, eswabs or others that do not use universal transport media) are not acceptable for measles PCR testing.

Storage and Transport Requirements

  • Place specimen in biohazard bag and seal.
  • Specimens should be stored in a refrigerator at 2-8°C following collection and shipped to the Public Health Ontario laboratory on ice packs.

Serology

  • Acute serology
    • Should be collected within 7 days of the onset of the rash.
    • Requisitions should be clearly marked "acute measles serology IgG and IgM."
  • Convalescent serology
    • Should be collected 7-10 days after the initial acute serology sample.
    • Requisition should be clearly marked "convalescent measles serology."
    • Convalescent serology is recommended if acute serology and virus detection are negative or indeterminate.

*Please note that if measles encephalitis or subacute sclerosing panencephalitis (SSPE) is suspected, please submit a CSF specimen and follow instructions as per the Public Health Ontario Laboratory website.

Reporting to Ottawa Public Health
  • Suspected or confirmed cases of measles, whether clinically diagnosed or laboratory confirmed, must be reported to Ottawa Public Health immediately by calling: 613-580-2424 ext. 24224 during normal business hours of Monday to Friday, 8:30 a.m. – 4:30 p.m. After hours and holidays, please call 3-1-1 and ask for the Communicable Disease Manager on-call. Reporting a suspected measles case should not be delayed pending the return of confirmatory laboratory results.
  • Ottawa Public Health will explain testing requirements and requirements for isolation of the patient. We will need the patient’s immunization history, symptoms and date of onset of, exposure history, and travel history outside Ottawa (if any in previous 21 days).
  • Because measles is very contagious, the sooner local public health can be involved in a suspected measles case, the sooner control measures and contact tracing can begin to reduce the spread to the public, particularly the most vulnerable.
  • If the suspected case is under 18 years old, the physician or health care professional is asked to also page the Infectious Diseases physician on-call at CHEO (613-737-7600 ext. 0) to discuss the symptoms, determine if the child meets clinical criteria, and if testing at CHEO is required. The physician or health care professional is then asked to follow-up with the public health nurse to advise on outcome of consultation so the public health nurse can proceed accordingly.
Management
  • Suspected or confirmed cases of measles, whether clinically diagnosed or laboratory confirmed, must be reported to Ottawa Public Health immediately by calling: 613-580-2424 ext. 24224 during normal business hours of Monday to Friday, 8:30 a.m. – 4:30 p.m. After hours and holidays, please call 3-1-1 and ask for the Communicable Disease Manager on-call. Reporting a suspected measles case should not be delayed pending the return of confirmatory laboratory results.
  • Please tell patients with suspected or confirmed measles to self-isolate at home until 4 days after the onset of rash. Children may not attend school or childcare. Adults may not attend work.
  • Measles is airborne, so please mask any patients with fever and rash immediately upon arrival, place them straight away into an examining room, schedule them preferably at day’s end, and do not use the room for other patients for 2 hours.
  • Please tell patients to avoid contact with pregnant women, immunocompromised individuals and infants under 12 months of age.
  • Ottawa Public Health will work to track people who may have been exposed to measles to prevent further spread.
  • If you think you, your staff or other patients have been exposed to a measles case contact Ottawa Public Health immediately
Prevention
  • Suspected or confirmed cases of measles, whether clinically diagnosed or laboratory confirmed, must be reported to Ottawa Public Health immediately by calling: 613-580-2424 ext. 24224 during normal business hours of Monday to Friday, 8:30 a.m. – 4:30 p.m. After hours and holidays, please call 3-1-1 and ask for the Communicable Disease Manager on-call. Reporting a suspected measles case should not be delayed pending the return of confirmatory laboratory results.

For Patients

  • Please tell patients with suspected or confirmed measles to self-isolate at home until 4 days after the onset of rash. Children may not attend school or childcare. Adults may not attend work.
  • Measles is airborne, so please mask any patients with fever and rash immediately upon arrival, place them straight away into an examining room, schedule them preferably at day’s end, and do not use the room for other patients for 2 hours.

For Health Care Workers (HCWs)

  • All HCWs (including but not limited to employees, physicians, nurses, contract workers, students, post-graduate medical trainees, researchers and volunteers), regardless of year of birth, should be immune to measles to prevent acquisition and transmission of the infection to others. Only the following are accepted as proof of measles immunity:
    • Documentation of receipt of 2 doses of measles-containing vaccine on or after the first birthday, with doses given at least four weeks apart (regardless of year of birth) OR
    • Laboratory evidence of immunity
  • Any HCW who has a significant exposure to a person who has measles, either in the health care setting or the community, must report this exposure to Occupational Health.

Health Care Workers exposed to measles

  • Exposed HCWs who are considered immune to measles (defined above): may continue to work without disruption and can be assigned to care for patients with suspected or confirmed measles.
  • Exposed HCWs who have previously received one dose of measles-containing vaccine who do not have laboratory evidence of measles immunity: should receive a second dose of a measles-containing vaccine (i.e. MMR vaccine) if no contraindications exist, and measles IgG should be ordered. Work restrictions may apply while waiting for serology results (see below).
    • If measles IgG is positive, the HCW is immune and may work.
    • If measles IgG is negative, the HCW is considered to be susceptible and should be excluded from work (see below)
  • Exposed HCWs who have no documentation of measles immunity (i.e. no previous serology for measles antibodies and no proof of having received measles containing vaccine): should receive one dose of a measles-containing vaccine (i.e. MMR vaccine) if no contraindications exist. They are considered susceptible and should be excluded from work (see below). Serology should be performed:
    • If measles IgG is positive, the HCW may return to work.
    • If measles IgG is negative, the HCW is considered to be susceptible and should be excluded from work.
  • Exposed HCWs who have negative serology for measles antibodies and who have never received measles containing vaccine, should receive a measles-containing vaccine (i.e. MMR vaccine) as soon as possible after the exposure if no contraindication exists, and should be excluded from work (see below). MMR vaccine given within 72 hours of exposure may provide protection after exposure, and when given beyond 72 hours may provide protection for subsequent exposures. If clinical measles does not develop after exposure, a second dose of measles-containing vaccine (i.e. MMR vaccine) should be given at least four weeks after the first.
  • Exposed HCWs in whom measles containing vaccine is contraindicated for medical reasons, (e.g. immunocompromised, pregnancy) must be offered human immune globulin within 6 days of exposure to prevent or modify measles. They are considered susceptible and should be excluded from work (see below). It is important to consider that immune globulin only provides short-term protection. For HCWs who can later receive MMR vaccine (e.g. pregnant HCWs), MMR vaccine should be postponed 5 to 6 months after immune globulin is administered.
  • If no immune staff are available and patient safety would be compromised, the susceptible HCW must wear a fit-tested, seal-checked N95 respirator. Theoretically, the respirator could provide protection from the airborne measles virus, however, there are no efficacy data for N95 respirators for this application.

Work Restrictions/Exclusion for Health Care Workers

  • Susceptible exposed HCWs must be excluded from any work in the hospital or any health care setting from 5 days after the first exposure until 21 days after the last exposure, regardless of whether they received MMR vaccine or immune globulin after the exposure.
  • HCWs must be excluded from work while waiting for serology results if they are still within the period of work exclusion defined above.
  • HCWs who are excluded from work should not work in any other health care setting. These HCWs should be counselled to disclose their work restrictions to other health care employer(s)
  • If clinical measles develops, the HCW must remain off work until 4 complete days have passed after the onset of the rash. Infected HCWs and their personal physician or health care professional are responsible for follow-up care and treatment.

Please refer to the Ontario Hospital Association Measles Surveillance Protocol for more information.

Immunization

Vaccine Background

  • Immunization provides the best protection against measles infection.
  • Measles containing vaccines include Measles-Mumps-Rubella (MMR) vaccine and Measles-Mumps-Rubella-Varicella (MMRV) vaccine.
  • Vaccination coverage needs to be at least 95% to develop herd immunity in a population and prevent transmission of the infection. In Ottawa, immunization coverage against measles is high.

Vaccine Effectiveness

  • Measles vaccines provide good immunity: ~85-95% of children will develop long-lasting protection against measles from the first dose of vaccine; close to 100% of children will have developed immunity to measles after the second dose.
  • In a well-immunized population (95% or more of school-aged children) an introduced case of measles usually does not lead to an outbreak. For each case, only about 50% to 80% of the time will there be a single additional case unless a subgroup of the community is involved in which children are unimmunized.
  • Immunity following vaccination is generally lifelong.

Recommendations

  • The Ontario Routine Immunization Schedule recommends two-doses of a measles-containing vaccine be given to children, given at least 1 month apart, after 12 months of age and again at 4 to 6 years of age.
  • If a child is travelling internationally to areas where measles is circulating, an initial dose of MMR vaccine can be given as early as 6 months, however, 2 additional doses of a measles-containing vaccine given at least 1 month apart must be administered after the child is 12 months old to ensure long lasting immunity to measles.

Immunization Records

  • Parent(s)/Guardian(s) are responsible for updating Ottawa Public Health every time their child receives immunizations given by their physician or health care professional.
  • As of November 2019, physicians and health care professionals are not mandated to report immunizations to Ottawa Public Health.
  • Patient can update their immunization records with Ottawa Public Health using either the online Immunization Connect Ontario (ICON) Tool or the CANImmunize App.
  • Patients can receive more information on vaccines from Ottawa Public Health’s Parenting in Ottawa website.

Contraindications

Considerations for Adult Immunizations

  • Adults born after 1970 may be under-immunized, having received only one MMR vaccine in childhood. If documentation of two measles-containing vaccines, given at least 1 month apart, after 12 months of age, is not available, immunization with MMR vaccine is recommended (without first checking serology for immune status).
  • Although most adults born before 1970 are considered to be immune from measles, there are several populations who require immunization:
    • Travel: Those born before 1970 who plan to travel outside North America require one dose of MMR vaccine to be considered immune.
    • Students in post-secondary educational settings born before 1970 require one dose of MMR vaccine to be considered immune.
    • Health care workers require either 2 doses of a measles-containing vaccine (given at least 1 month apart, after 12 months of age), laboratory confirmed measles illness, or measles serology to prove immunity, regardless of year of birth.
    • Members of the military require either 2 doses of a measles-containing vaccine (given at least 1 month apart, after 12 months of age), laboratory confirmed measles illness, or measles serology to prove immunity, regardless of year of birth.
    • More details regarding requirements for immunity in special populations can be accessed in the Canadian Immunization Guide (Measles Vaccine: Table 1).
  • Unknown Immunization Status: Immunization vs. Serology
    • If a patient’s immunization records are unavailable, immunization with measles-containing vaccine is preferred, rather than ordering serology to determine immune status.
    • This avoids the potential for false positive results, reduces the risk of missed opportunities for immunization and is consistent with advice from the Canadian Immunization Guide
    • Please note this may not apply to specific occupational groups such as health care workers who require either documentation of immunization or serologic proof of immunity. Please refer to the Ontario Hospital Association Measles Surveillance Protocol for more information.

Adverse events

  • Measles-Mumps-Rubella (MMR) vaccine: Adverse events following immunization occur less frequently and are less severe than those associated with natural infection. Six to 23 days after immunization with MMR vaccine, approximately 5% of immunized children experience malaise and fever (with or without rash) lasting up to 3 days. Parotitis, rash, lymphadenopathy, and joint symptoms also occur occasionally after immunization with MMR vaccine.
  • Measles-Mumps-Rubella-Varicella (MMRV) vaccine: Pain and redness at the injection site or fever less than 39°C occur in 10% or more of vaccine recipients. Rash, including measles-like, rubella-like and varicella-like rash, as well as swelling at the injection site and fever greater than 39°C, occur in 1% to less than 10% of vaccine recipients

Resources

Public Health Role
  • Using the Health Protection and Promotion Act, S.O. 2007 Ottawa Public Health will take actions to protect the public and prevent the spread of measles to the public.
    • Ottawa Public Health works with health care professionals to facilitate post-exposure prophylaxis to some contacts of measles.
    • Ottawa Public Health works with community stakeholders (childcare, schools, and workplaces) to ensure those sick with measles are isolated at home and excluded from childcare, school, or work during periods of communicability.

Control measures

  • Childcare exclusion: Ottawa Public Health requires susceptible contacts of a case of measles to be excluded from childcare from 5 days after the first exposure until 21 days after the last exposure.
  • School exclusion: The Immunization of School Pupils Act, R.S.O. 1990, c. I.1 requires Ottawa Public Health to exclude students exposed to measles who do not have proper documentation of immunization against measles from school. Ottawa Public Health requires susceptible contacts of a case of measles to be excluded from school from 5 days after the first exposure until 21 days after the last exposure.
  • Work exclusion: Ottawa Public Health requires certain susceptible contacts of a case of measles to be excluded work (i.e. those who work in childcare, school, or health care setting) from 5 days after the first exposure until 21 days after the last exposure.
Patient information
Physican Resources

Measles testing

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