Healthcare personnel measles immune status and exposures in healthcare settings

Information on evaluating healthcare workers' measles immune status and responding to exposures in healthcare settings.

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MMR efficacy
Measles disease history
Healthcare workers' measles immune status should be evaluated
Vaccination recommendation for healthcare workers
Age groups presumed immune to measles due to disease
Healthcare worker exposure
Infectious period for measles
Inpatient, outpatient, or LTCF resident exposure
Hospital or LTCF visitor exposure
Outbreak control

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. Suspected measles cases should be immediately reported to MDH to facilitate case confirmation and ensure a rapid public health response.

MMR efficacy

  • Measles vaccine (generally given in conjunction with mumps and rubella vaccine as MMR) is considered to be 95% (range 90-98%) effective at preventing measles after one dose, and 99% effective after two doses. 
  • The duration of vaccine-induced immunity is believed to be lifelong in most vaccine recipients. A small proportion (<5%) may lose protection after several years.

Measles disease history

  • Measles disease is considered to confer lifelong immunity.

Healthcare workers' measles immune status should be evaluated

Healthcare workers include everyone working in a healthcare 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 healthcare workers includes:

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

Healthcare workers born before 1947 are not exempt from the above immunity criteria.

Vaccination recommendation for healthcare workers

Healthcare workers without evidence of immunity should receive either:

  • Two doses MMR vaccine (CDC. Immunization of Health-Care Workers: Recommendations of the Advisory Committee on Immunization Practices (ACIP) and the Hospital Infection Control Practices Advisory Committee (HICPAC). MMWR 1997; 46(RR-18):1-42); or
  • Serologic immune status testing, with follow-up vaccination of persons with negative or equivocal results. Note: 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., immune compromised patients). Healthcare worker age may also assist with prioritization. Persons born in or after 1976 who went to school in Minnesota are more likely to have received two 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% 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. Therefore, during measles outbreaks, MMR vaccination should be considered for persons born before 1957 who may be exposed to measles and who may be susceptible. Laboratory testing for measles susceptibility before vaccination is not necessary.

Healthcare worker exposure

Because measles is so highly infectious, exposure is defined as having shared air at the same time or, in a closed area, up to two hours after a person with measles has occupied the area. 

Determining healthcare worker immune status 

Evaluate healthcare workers' measles immune status using the criteria above.

Healthcare workers with measles symptoms

A healthcare worker who develops known or suspect measles should be excluded from work until 4 days after rash onset, or until measles is ruled out. 

Exposed non-immune healthcare workers

Measles (or MMR) vaccine has been demonstrated to be effective at preventing measles when administered to a susceptible person within 72 hours following exposure.

Immune Globulin (IG) will prevent or modify measles disease in susceptible persons when given within 6 days following exposure. IG is recommended only for susceptible close contacts, particularly children under one year of age, pregnant women, and immune compromised persons for whom the risk of complications is highest. IG is not routinely recommended for susceptible healthcare workers. All healthcare workers should be vaccinated unless medically contraindicated. (American Academy of Pediatrics.  Measles. In: Pickering LK, Baker CJ, Long SS, McMillan JA, eds. Red Book: 2006 Report of the Committee on Infectious Diseases, 27th ed. Elk Gove Village, IL: American Academy of Pediatrics, 2006: [443-444])

Infectious period for measles

Cases are infectious from 4 days before until 4 days after rash onset.

Furlough of exposed healthcare workers
Standard recommendations state that non-immune healthcare workers who are exposed to measles should be furloughed from work beginning 5 days through the 21st day following exposure. (2005 APIC Text of Infection Control and Epidemiology, 2nd ed. Washington, DC: Association for Professionals in Infection Control and Epidemiology, 2005:86-1 through 86-8)

Furlough is recommended regardless of whether the employee receives post-exposure vaccine or IG.

Serologic Testing

  • Persons immune to measles due to disease or immunization will likely test positive for measles serum IgG. Serum IgG rises soon after infection or immunization, and persists.
  • Measles serology can have variable sensitivity and specificity.
  • Measles IgG in immune persons is not thought to fall below detectable levels in the absence of exposure.
  • Immune status testing may be performed post-exposure; however, testing should be performed as soon after exposure as possible because measles IgG due to measles infection may rise prior to onset of symptoms.
  • Any standard serologic assay for measles IgG is acceptable. Commercially available tests for determining measles immune status vary in sensitivity and specificity. While post-exposure immune status testing may be useful, results should not be considered definitive and therefore should be considered, but not relied upon, in making decisions regarding susceptibility and furloughing employees.
  • Persons with negative or equivocal immune status test results should receive measles (preferably MMR) vaccine.

Inpatient, outpatient, or LTCF resident exposure

Because measles is so highly infectious, exposure is defined as having shared air at the same time or, in a closed area, up to two hours after a person with measles has occupied the area.

The general public is considered immune to measles if they:      

  • Were born before 1957; or
  • Have a history of measles disease; or
  • Have received at least one (preferably two) doses of measles (or MMR) vaccine; or
  • Have serologic evidence of immunity.

Exposed patients/residents should be:

  • Notified of their exposure,
  • Queried about measles disease and vaccine history,
  • Evaluated and offered IG, if indicated (see indications, above)
  • Offered MMR vaccine, if indicated
  • Placed in isolation (if possible) with airborne precautions, and monitored for symptoms from days 7 through 18 post-exposure, unless known to be immune, and
  • Monitored for or, if discharged, asked to report to their healthcare provider any onset of symptoms within 18 days of exposure.

Hospital or LTCF visitor exposure

Visitors exposed to measles should be notified of their possible exposure, recommended to consult with their healthcare provider if unsure of their susceptibility to measles, and asked to notify their healthcare provider any onset of symptoms within 18 days of exposure by phone prior to presenting in clinic. Persons exposed should be advised to limit potentially exposing others from 7 through 18 days following exposure. In some situations, MDH may recommend quarantine of exposed persons.

Outbreak control

If measles occurs in a healthcare facility, all persons working in the facility who are not considered immune should receive two doses of MMR vaccine.  Healthcare workers born in or after 1957 who have received only one dose of measles/MMR vaccine and do not have serologic evidence of immunity should receive a second dose. Second dose MMR vaccine should be given at least 28 days after the first dose. During an outbreak, serologic testing of healthcare workers before vaccinating is not recommended, as waiting for results can delay vaccination to halt transmission.

Note: MMR vaccine is a live virus vaccine, and should not be administered during pregnancy, or to persons who are severely immune compromised. (Measles, Mumps, Rubella – Vaccine Use and Strategies for Elimination of Measles, Rubella, and Congenital Rubella Syndrome, and Control of Mumps: Recommendations of the Advisory Committee on Immunization Practices [ACIP]. MMWR 1998; 47[32-36])

Updated Wednesday, April 20, 2011 at 01:03PM