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Also known as rubeola.

Reporting Information

Class A

Report a case, suspected case, and/or positive laboratory result immediately via telephone to the local public health department in which the patient resides.  If patient residence is unknown, report immediately via telephone to the local public health department in which the reporting healthcare provider or laboratory is located.  Local public health departments should report immediately via telephone the case, suspected case, and/or a positive laboratory result to the Ohio Department of Health (ODH).

Reporting Form(s) and/or Mechanism

Immediate telephone reporting is required.

The local public health department should enter the case into the Ohio Disease Reporting System (ODRS) within 24 hours after the telephone report.

The Measles Surveillance Worksheet (CDC) is available for use by the local public health department when following up with cases.  Do not send this form to ODH unless otherwise requested; information collected from the form should be entered into ODRS where fields are available, and the form should be uploaded in the Administration section of ODRS.


Measles virus, an RNA virus with one antigenic type.  It is a paramyxovirus of the genus Morbillivirus.

Case Definition

Clinical Case Definition

An illness characterized by all of the following:

  • Generalized rash lasting ≥3 days,
  • Temperature ≥101°F (≥38.3°C),
  • Cough, coryza, or conjunctivitis.

Laboratory Criteria for Diagnosis

  • Positive serologic test for measles immunoglobulin M (IgM) antibody or
  • Significant rise in measles antibody level by any standard serologic assay or
  • Isolation of measles virus from a clinical specimen or
  • Detection of measles-virus specific nucleic acid by polymerase chain reaction.

Case Classification


A case that meets the clinical case definition, has non-contributory or no serologic or virologic testing, and is not epidemiologically linked to a laboratory confirmed case of measles.


An acute febrile rash illness† with:

  • Isolation of measles virus‡ from a clinical specimen; or
  • Detection of measles-virus specific nucleic acid‡ from a clinical specimen using polymerase chain reaction; or
  • IgG seroconversion‡ or a significant rise in measles immunoglobulin G antibody‡ using any evaluated and validated method; or
  • A positive serologic test for measles immunoglobulin M antibody‡§; or
  • Direct epidemiologic linkage to a case confirmed by one of the methods above.

† Temperature does not need to reach ≥101°F/38.3°C and rash does not need to last ≥3 days.

‡ Not explained by MMR vaccination during the previous 6-45 days.

§ Not otherwise ruled out by other confirmatory testing or more specific measles testing in a public health laboratory.

Not a Case

This status will not generally be used when reporting a case, but may be used to reclassify a report if the investigation revealed that it was not a case.


In Ohio, two probable cases that are epidemiologically linked but not serologically confirmed would be considered to be confirmed.  However, an attempt should be made to confirm at least one case by culture in each documented chain of transmission.

An outbreak is defined as more than 3 cases (with at least one laboratory confirmed case) clustered in space and time.  Active surveillance should be maintained for at least two incubation periods (42 days) after the last confirmed case is reported.

Epidemiologic Classification for Measles of Internationally-Imported and U.S.-Acquired

Internationally Imported Case

An internationally imported case is defined as a case in which measles results from exposure to measles virus outside the United States as evidenced by at least some of the exposure period (7-21 days before rash onset) occurring outside the United States and rash onset occurring within 21 days of entering the United States and there is no known exposure to measles in the U.S. during that time.  All other cases are considered U.S.-acquired.

U.S.-Acquired Case

A U.S.-acquired case is defined as a case in which the patient had not been outside the United States during the 21 days before rash onset or was known to have been exposed to measles within the United States.

U.S.-acquired cases are sub-classified into four mutually exclusive groups:

  • Import-linked case: Any case in a chain of transmission that is epidemiologically linked to an internationally imported case.
  • Imported-virus case: A case for which an epidemiologic link to an internationally imported case was not identified, but for which viral genetic evidence indicates an imported measles genotype (i.e., a genotype that is not occurring within the United States in a pattern indicative of endemic transmission).  An endemic genotype is the genotype of any measles virus that occurs in an endemic chain of transmission (i.e., lasting ≥12 months).  Any genotype that is found repeatedly in U.S.-acquired cases should be thoroughly investigated as a potential endemic genotype, especially if the cases are closely related in time or location.
  • Endemic case: A case for which epidemiological or virological evidence indicates an endemic chain of transmission.  Endemic transmission is defined as a chain of measles virus transmission that is continuous for ≥12 months within the United States.
  • Unknown source case: A case for which an epidemiological or virological link to importation or to endemic transmission within the U.S. cannot be established after a thorough investigation.  These cases must be carefully assessed epidemiologically to assure that they do not represent a sustained U.S.-acquired chain of transmission or an endemic chain of transmission within the U.S..

Note 1: Internationally imported, import-linked, and imported-virus cases are considered collectively to be import-associated cases.

Note 2: States may also choose to classify cases as "out-of-state-imported" when imported from another state in the United States.  For national reporting, however, cases will be classified as either internationally imported or U.S.-acquired.

Signs and Symptoms

Measles infections classically are described as having a prodromal period with a fever of 103-105°F, coryza, conjunctivitis, cough, and photophobia for 2-4 days.  Then a maculopapular rash appears on the face which spreads to the trunk and finally to the extremities.  The rash and other symptoms normally subside in 7-9 days.  Koplik spots may be observed on the buccal mucosa just prior to and on the first day of the rash.  Complications of measles include otitis media, pneumonia, cardiac manifestations, encephalitis, and occasionally death.  A slow virus disease associated with the measles virus is subacute sclerosing panencephalitis (SSPE).

Atypical measles syndrome (AMS) occurs in individuals who have received two or more doses of inactivated measles vaccine and is characterized by a rash on the extremities, high fever, and frequently pneumonia.

Modified measles occurs in infants who still have maternal antibodies and in those who received measles vaccine or immune globulin soon after exposure.


The most common methods for confirmatory measles testing are IgM antibody and RNA by real-time PCR (RT-PCR).  Clinical specimens for RT-PCR and virus isolation should be collected at the same time as samples for serologic testing.  Specimens for virus isolation and RNA detection should be collected within three days of rash onset.  The preferred specimens for virus isolation or RT-PCR are throat and nasopharyngeal swabs.

IgM tests are often positive on the day of rash onset.  However, up to 20% of tests for IgM may give false-negative results in the first 72 hours of rash onset.  Therefore, IgM tests that are negative in the first 72 hours after rash onset should be repeated.  IgM obtained four days after the onset of rash is the preferred laboratory diagnostic procedure.  IgM is detectable for at least 28 days after rash onset.  If the titer is negative at that time, it can be repeated at seven days, or paired acute and convalescent sera can be tested for an increase in IgG antibody.  The acute specimen should be taken as close to rash onset as possible, and the convalescent specimen drawn two weeks after the acute.  The latter method is less desirable because of the delay in definitive diagnosis.

When laboratory specimens need tested or verified, they may be sent to a public health laboratory.  For serum specimens, complete the ODH Laboratory Microbiology Specimen Submission Form (HEA 2530) and the CDC Specimen Submission Form (CDC 50.34).  For swab specimens, complete the ODH Laboratory Microbiology Specimen Submission Form (HEA 2530) and the Wisconsin (WI) VPD Submission Form.

Please notify the ODH VPD Epidemiology Program at (614) 995-5599 before shipping a specimen to the ODH Laboratory.

Note 1: Negative culture or negative RT-PCR results do not rule out measles because both methods are affected by the timing of specimen collection and the quality and handling of clinical specimens.



Humans are the only natural host of the measles virus.


Prior to the licensure of measles vaccine, the disease was widespread and common in childhood with over 90% of individuals having the disease by 20 years of age.  Recently measles has been seen most frequently in preschool children and in young adults attending high schools or colleges.  Measles occurs primarily in late winter and early spring.

Mode of Transmission

The virus is transmitted through airborne spread of droplet nuclei or direct contact with nasal or throat secretions of infected persons; droplet nuclei can remain suspended in the air for up to two hours.  Measles virus is highly communicable.

Period of Communicability

Communicability is greatest from four days before the onset of rash until four days after the onset of rash.

Incubation Period

The average incubation period for measles is 14 days, with a range of 7-21 days.

Public Health Management



Local health agencies should report suspected cases immediately and complete the Measles Surveillance Worksheet (CDC).  Prompt recognition, reporting, and investigation of measles is important because the spread of the disease can be limited with early case identification and public health response including vaccination and quarantine of susceptible contacts without presumptive evidence of immunity.


Ohio Administrative Code (OAC) 3701-3-13 (M) states:

"Measles: a person with measles shall be isolated, including exclusion from school or child care center, for four days following the onset of rash.  Contagiousness may be prolonged in patients with altered immunity."

Isolation of the Hospitalized Patient

Airborne isolation precautions are indicated for four days after the onset of rash in otherwise healthy individuals and for the duration of the entire illness in immunocompromised patients.


All contacts should provide proof of a live measles immunization on or after their first birthday or previously physician diagnosed measles disease.  In an outbreak situation involving child care or schools, demonstration of two doses of MMR will be required.  Generally those born prior to 1957 are considered immune.  Contacts who might be susceptible should be immunized with measles vaccine as soon after exposure as possible.  Measles vaccine given within 72 hours after exposure may prevent or modify the disease.

Immune globulin (IG) can prevent or modify measles in a susceptible person if given within six days of exposure.  IG may be especially indicated for susceptible household contacts <1 year of age, pregnant women, or immunocompromised persons, for whom the risk of complications is increased.  If IG is administered, the monitoring and quarantine period is extended to 28 days.

Subsequent immunization should then be delayed for five to six months (depending on the dose to allow passive antibody to disappear) and until the individual is at least 12 months old.

Prevention and Control

Susceptible persons who refuse immunization should be excluded from contact in schools and child care centers until 21 days after the last case has occurred.

Day Care Centers, Schools, and Other Educational Institutions

Measles cases in schools, colleges, and other institutions, such as day care centers where close contact may exist, require rapid public health investigation for response and for evaluation of risk of further transmission.  In educational institutions where there are high rates of vaccine exemption, the potential risk of spread of the disease is high.  Control measures include the following actions:

  • Exclusion and isolation of cases (they can return on the fifth day after rash onset if not immunocompromised).
  • Offering vaccine for those who are not up-to-date with age-appropriate vaccination (first dose to unvaccinated, second dose to those with one documented dose can be given at least 28 days after the first dose).
  • IG if immunocompromised (please refer the following section: Postexposure vaccination and use of immunoglobulin to prevent measles in exposed susceptible persons).
  • Persons who continue to be exempted from or who refuse measles vaccination should be excluded from the school, child care, or other institutions until 21 days after rash onset in the last case of measles.

All students and all school personnel born in or after 1957 who cannot provide adequate presumptive evidence of immunity should be vaccinated.  Students with one dose of measles containing vaccine do not require exclusion and if symptoms develop, the student should isolate immediately and report to public health.  Previously unvaccinated persons receiving their first dose appropriately (i.e., before, or within 72 hours of, exposure) as part of the outbreak control program may be immediately readmitted to school.  However, these individuals should be monitored for signs and symptoms of measles.

IG should not be used in an attempt to control measles outbreaks.


Please refer to the ODH Vaccine Protocol Manual or the most current Advisory Committee on Immunization Practices (ACIP) recommendations for measles vaccination with MMR.

Minimizing Transmission in Healthcare Settings

To minimize the risk of measles transmission in healthcare settings, healthcare personnel should do the following:

  1. Query patients with a febrile rash illness about a history of international travel, contact with foreign visitors, transit through an international airport, or possible exposure to a person with measles in the 3 weeks prior to symptom onset. Possibility of measles should be considered for patients with such a history and symptoms consistent with measles.
  2. Patients with suspected measles should immediately be provided a face mask to wear, if tolerated.  Encourage respiratory etiquette.
  3. Do not allow patients with suspected measles to remain in the waiting room or other common areas; isolate patients with suspected measles immediately in an airborne infection isolation room if one is available. If such a room is not available, place patient in a private room with the door closed. For additional infection control information, please refer to the CDC's control measures for measles.
  4. If possible, allow only healthcare personnel with documentation of two doses of MMR vaccine or laboratory evidence of immunity to measles (i.e., measles IgG positive) to enter the patient's room.
  5. Healthcare personnel should wear an N95 or higher-level respirator regardless of presumptive evidence of immunity.  (A user seal check should be performed each time the respirator is donned.)
  6. If possible, do not allow susceptible visitors in the patient room.
  7. Do not use the examination room for at least two hours after the possibly infectious patient leaves.
  8. If possible, schedule patients with suspected measles at the end of the day.
  9. Notify the local health department in whose jurisdiction the patient resides immediately by telephone about any patients with suspected measles.
  10. Notify any location where the patient is being referred for additional clinical evaluation or laboratory testing about the patient's suspected measles status, and do not refer patients with suspected measles to other locations unless appropriate infection control measures can be implemented at those locations.  The patient must wear a mask, if feasible.
  11. Instruct patients with suspected measles and exposed persons to inform all healthcare providers of the possibility of measles prior to entering a healthcare facility so appropriate infection control precautions can be implemented.
  12. Make note of the staff and other patients who were in the area during the time the patient with suspected measles was in the facility and for two hours after they left.  If measles is confirmed, exposed people will need to be assessed for measles immunity. 
Revised 12/5/2022.