Health Care Worker Measles Immune Status and Exposures in Health Care Settings

Information for employee health and infection prevention staff on evaluating health care workers' measles immune status and responding to exposures in health care settings.

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Report suspect measles cases immediately
Health care workers' measles immune status should be evaluated
Vaccination recommendation for HCWs
Age groups presumed immune to measles due to disease
Minimizing measles transmission
Health care worker exposure
Patient exposure

Report suspect measles cases immediately

If you suspect measles in a patient, call MDH at
651-201-5414 or toll-free at 1-877-676-5414. 

Health care facilities are required by law to report suspect cases of measles immediately to MDH to facilitate case confirmation and ensure a rapid public health response.

Measles is a highly infectious disease. Although it is no longer endemic in the U.S., an imported case can spread rapidly to susceptible individuals or groups.

Health care workers’ measles immune status should be evaluated

Health care workers (HCWs) include everyone working in a health care facility that has the potential for exposure to infectious materials. Workers providing direct, face-to-face patient care should be prioritized. Evidence of measles immunity for HCWs, regardless of when they were born, includes (1):

  • Having had two doses of measles/MMR vaccine, or
  • Serologic evidence of immunity, or
  • Laboratory confirmation of disease.

If a person is not immune, they should be considered susceptible. History of disease is no longer considered adequate presumptive evidence of measles immunity for HCWs; laboratory confirmation of disease has been added as acceptable presumptive evidence of immunity (2).
For HCWs with 2 documented doses of MMR or other acceptable evidence of immunity to measles, serologic testing for immunity is not recommended.

  • If a HCW has 2 documented doses of MMR, is tested serologically, and has negative or equivocal measles titer results, it is not recommended that the person receive an additional dose of MMR vaccine. They should be considered to have adequate presumptive evidence of immunity.
  • If a HCW has 1 documented dose of MMR, they should receive a second dose at least 28 days after the first.
  • A secure, preferably computerized system should be used to manage vaccination records for HCWs so records can be retrieved easily as needed (2).

Vaccination recommendation for HCWs

HCWs without evidence of immunity should receive either:

  • Two doses MMR vaccine, or
  • Serologic immune status testing with follow-up vaccination of persons with negative or equivocal results.

In HCWs without evidence of immunity, serologic testing prior to vaccination is not recommended unless the facility deems it more cost-effective.

Priority for vaccination of staff should be based on risk of contact with measles cases (e.g., outpatient clinics, emergency departments), and patient population served (e.g., immunocompromised patients). Persons born in or after 1976 who went to school in Minnesota are more likely to have received 2 doses of measles vaccine, required by Minnesota School Law for students in grades 7 and 12 beginning in 1992.

Age groups presumed immune to measles due to disease

Before measles vaccine was introduced in 1963, more than 90 percent of U.S. children were immune by age 15 years. Most persons born before 1957 are likely to have been infected naturally and may be presumed to be immune. However, birth before 1957 does not guarantee measles immunity.

For HCWs born before 1957 who lack evidence of measles immunity, health care facilities should consider vaccinating with 2 doses of MMR at the appropriate interval. Laboratory testing for measles susceptibility before vaccination is not necessary.

Minimizing measles transmission

Measles cases are infectious from 4 days before until 4 days after rash onset, which is when they are likely to seek medical care.

See Minimize Measles Transmission in Health Care Settings.

Health care worker exposure

Exposure is typically defined as having shared airspace at the same time or, in a closed area, up to two hours after a person with measles has occupied the area. If a suspect case of measles at your facility is confirmed, the following should be done:

  • Evaluate HCWs’ measles immune status utilizing criteria on page 1.
  • Contact MDH to discuss PEP and exclusion.

Post-exposure Prophylaxis for exposed, non-immune HCWs

Measles (or MMR) vaccine is effective at preventing measles when administered to a susceptible person within 72 hours following exposure. Immune Globulin (IG) may prevent or modify measles disease in susceptible persons when given within 6 days following exposure.

Exclusion of exposed HCWs
Susceptible HCWs who are exposed to measles should be excluded from work beginning 5 days through the 21st day following exposure. Exclusion is recommended regardless of whether the employee receives post-exposure vaccine or IG.

Exposed HCWs with symptoms
A HCW who develops measles symptoms after exposure should be excluded from work until 4 days after rash onset, or until measles is ruled out.

Serologic Testing
Persons immune to measles due to disease or immunization will likely test positive for measles serum IgG (immune globulin G).

  • Serum IgG rises soon after infection or immunization, and persists.
  • Serum IgM should not be run on individuals for immunity testing. The IgM may be (falsely) positive in previously vaccinated, asymptomatic individuals.
  • Serologic test results should be interpreted with caution as serology has variable sensitivity and specificity.

Immune status testing may be performed post-exposure; however:

  • Testing should be performed as soon after exposure as possible because IgG due to measles infection may rise prior to onset of symptoms.
  • Results should be considered, but not relied upon, in making decisions regarding susceptibility and exluding employees.

Patient exposures

MDH should be notified immediately of any suspect cases. MDH and local health departments will work with the facility to determine roles and responsibilities in contact investigations.

Inpatient, outpatient, or LTCF resident exposure
Exposed patients/residents should be:

  • Notified of their exposure.
  • Asked about measles disease and vaccine history.
  • Evaluated and offered IG, if indicated.
  • Offered MMR vaccine, if indicated.
  • Placed in isolation (if possible) with airborne precautions, and monitored for symptoms from days 7 through 21 post-exposure, unless known to be immune.
  • Monitored for or, if discharged, asked to report to their health care provider any onset of symptoms within 21 days of exposure.

Hospital or LTCF visitor exposure
Visitors exposed to measles should be:

  • Notified of their possible exposure.
  • Recommended to consult with their health care provider if unsure of their susceptibility to measles.
  • Asked to notify their health care provider regarding any onset of symptoms within 21 days of exposure by phone prior to going in to the clinic.


  1. CDC. Prevention of Measles, Rubella, Congenital Rubella Syndrome, and Mumps 2013. MMWR 2013;62(No. 4):1-40.
  2. CDC. Immunization of Health-Care Personnel: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR November 25, 2011; 60(No. RR-07); 1-45.

Updated Friday, June 19, 2015 at 11:32AM