Measles

Measles Information for Health Care Providers

Notifications and responsibilities:

Immediately report all suspected cases directly to San Mateo County Communicable Disease Control at 650-573-2346. In addition, if the case is or was in the hospital, notify the hospital ICP. Do not wait for laboratory results before notifications.

Diagnosis:

Testing via the Public Health Laboratory system should be pursued immediately for all suspect cases. Do not delay diagnosis by sending specimens to commercial laboratories. Measles can be diagnosed by serology (a positive IgM collected 4-28 days after rash or a significant rise in IgG), and by isolation and/or nucleic acid amplification testing from throat or urine specimens. Obtain serum in a serum separator tube, a throat swab on a Dacron-tipped swab placed in viral transport media and a urine sample in any container (does not need to be sterile). After consultation with San Mateo County Communicable Disease Control, specimens should be sent to the San Mateo County Public Health Laboratory at 225-37th Avenue, San Mateo, CA 94403 (phone 650-573-2500).

Identification of exposed persons (contacts):

All contacts of suspect measles cases should be identified, their susceptibility determined and reported to San Mateo County Communicable Disease Control. In the hospital setting, ICPs will usually coordinate this process. In clinics and offices, clinicians should collaborate with San Mateo County Communicable Disease Control. In non-medical settings, San Mateo County Communicable Disease Control manages identification of contacts to confirmed and suspect cases and communicates directly with contacts if specific interventions are recommended.

A person is considered a contact if, during the case’s infectious period, the individual:

a. Lived with the case.
b. Shared air space with the case for thirty minutes or more, and was not wearing a mask at the time.

Identification of susceptibility or immunity:

A person is considered susceptible to measles if they answer “No” to ALL the questions below. A person is considered immune if they answer “Yes” to any of these questions:

a. Were you born before 1957?
b. Do you have documentation of 2 doses of measles vaccine?
c. Do you have a history of measles with a physician’s documentation of the infection?
d. Do you have laboratory evidence of measles immunity?

Some contacts to a measles case are unable to produce documentation of receipt of two doses of measles-containing vaccine, and some have received only one dose of measles-containing vaccine. These persons may request measles serology testing (IgG) to assess for immunity. Providing this testing may prevent or shorten the duration of quarantine if immunity to measles can be demonstrated by serologic testing.

Post-exposure prophylaxis (PEP):

If additional cases occur and are promptly recognized, PEP should be pursued for exposed susceptible contacts:

1. The measles-mumps-rubella (MMR) vaccine is recommended as PEP for most susceptible persons aged older than 12 months. Administration of MMR is preferable to using Immune Globulin (IG), except as noted below. If administered within 72 hours of initial exposure, MMR or other measles-containing vaccine (MCV) may provide some protection. MCV is available in monovalent (measles only) formulation and in combination formulations, such as measles-rubella (MR) and measles-mumps-rubella (MMR) vaccines.
   1. MMR may be given before 12 months of age, but should not be counted as a valid dose. An MMR dose administered before 12 months of age may provide protection from current exposure, but repeat vaccination is still recommended. For young infants, you may wish to consult with a pediatric infectious disease specialist.
   2. A second dose of MMR may be given at any time at least four weeks after the first dose. It may boost antibody titers in some persons.
2. Immune globulin (IG) can prevent or modify measles in a non-immune person if given within six days of exposure. IG is indicated for susceptible contacts at high risk for developing severe measles, including some infants less than 12 months old, pregnant women, immunocompromised persons and others for whom the vaccine is contraindicated. Severely immunocompromised patients and other symptomatic HIV-infected patients exposed to measles should receive IG, regardless of vaccination status, because the vaccine may not protect them. Infants less than 6 months old are usually immune because of passively acquired maternal antibodies. However, if measles is diagnosed in a mother, unvaccinated children in the household who lack evidence of measles immunity should receive IG.