Measles

• Reporting criteria
• The disease and its epidemiology
• Clinical description
• Case classification 

• Laboratory testing recommendations
• Case investigation
• Contact investigation 
• Disease control recommendations for contacts

• Emergency preparedness and response
• Managing special situations
• Additional resources
• References

What and how to report to the Colorado Department of Public Health and Environment (CDPHE) or local public health agency  

• All people suspected of having measles, whether or not laboratory data are available, should be reported IMMEDIATELY.
• Suspect cases require immediate attention and should be reported by telephone to CDPHE or local public health agencies, or followed up with a telephone call if reported by fax or through the Reportal or EpiTrax. See below for phone and fax numbers.
  • Important telephone and fax numbers 
    • CDPHE Communicable Disease Branch 
      • Phone: 303-692-2700 or 800-866-2759 
      • Email: cdphe_vpd@state.co.us 
      • After hours: 303-370-9395 
      • Fax: 303-782-0338 

Purpose of surveillance and reporting

• Identify cases for investigation. 
• Identify sources and sites of transmission and any additional cases. 
• Identify exposed people, assure timely administration of prophylactic vaccination, and prevent further spread of the disease. 
• Promptly identify clusters and potential outbreaks of disease. 
• Monitor trends in disease incidence. 
• Monitor vaccine coverage of at-risk populations. 

Back to top

Etiologic agent 

Measles virus is an RNA virus with one serotype, classified as a member of the genus Morbillivirus in the Paramyxoviridae family. 

Clinical description 

Measles (also known as rubeola) is characterized by a prodrome of fever (as high as 105°F) and malaise, cough, coryza (runny nose), and conjunctivitis, followed by a maculopapular rash (rash images available on CDC’s website). The rash typically starts on the head along the hairline then spreads to the trunk and lower extremities. The rash has been described as a “bucket of measles” due to the way the rash spreads like it was poured down from the head to the body. Koplik spots, which are tiny white lesions on the buccal mucosa, sometimes appear during the prodrome. 

Approximately 30% of reported measles cases have one or more complications. Complications are more common among children younger than aged 5 years, and adults older than 20 years. Diarrhea, otitis media (ear infection), croup, and pneumonia commonly occur in young children. Acute encephalitis, which may result in permanent brain damage, occurs in approximately one out of every 1,000 cases. Death, predominantly due to respiratory and neurological complications, occurs in one to three out of every 1,000 cases reported in the United States. 

Treatment 

No specific antiviral treatment is available. 

Supportive care, including vitami

n A administration under the direction of a physician, may be appropriate. Vitamin A does not prevent measles infection. Overuse of Vitamin A can lead to toxicity and cause damage to the liver, bones, central nervous system, and skin. Vitamin A dosing can be found at the CDC webpage, Clinical Overview of Measles. 

Reservoirs 

Humans are the only known host. An asymptomatic carrier state has not been documented. 

Modes of transmission 

Measles is transmitted primarily via large respiratory droplets or direct contact with infectious droplets. Airborne transmission via aerosolized droplet nuclei has been documented in closed areas (e.g., office examination room) for up to two hours after a person with measles occupied the area. 

Incubation period 

The incubation period is usually 8 to 14 days (range of 7 to 21 days). In rare circumstances, a person who is immunocompromised may have a longer incubation period. 

Period of communicability or infectious period 

Measles is highly communicable with greater than 90% secondary attack rates among susceptible people. Typically, a person is infectious for four days before to four days after rash onset. 
People are thought to be most infectious 1 to 2 days before rash onset through the first four days of rash. People with T-cell deficiencies (particularly people with leukemia, lymphoma, and AIDS) may shed virus for several weeks after the acute illness. 

Epidemiology 

Before the introduction of the measles vaccine in 1963, infection with measles virus was nearly universal during childhood, and more than 90% of people were immune by age 15 years. The highest incidence was among children aged 5 to 9 years, who generally accounted for more than 50% of reported cases. Following the licensure of the vaccine in 1963, the incidence of measles decreased by more than 98%. Fewer than 150 cases were reported each year during 1997–2004, and measles incidence decreased to a record low of 37 cases reported nationwide in 2004. However, the disease is still common throughout the world, including some countries in Europe, Asia, the Pacific, and Africa. 

While measles is no longer endemic in the United States, cases and outbreaks continue to result from United States residents who travel abroad to places with measles and visitors to the United States. More recently, the United States has had several notable measles outbreaks. In 2024, Chicago experienced a measles outbreak of 57 cases associated with a migrant shelter. In early 2025, a large measles outbreak with over 200 cases were identified in under-vaccinated communities in Texas and New Mexico. Outbreaks in the US have historically been associated with insular communities with low vaccination rates. CDC maintains a summary of measles cases and outbreaks on their website. 

Vaccination 

Measles vaccine is incorporated with mumps and rubella vaccine or with mumps, rubella, and varicella as a combined vaccine (MMR or MMRV, respectively). The Advisory Committee on Immunization Practices (ACIP) recommends children routinely receive a first dose at 12 to 15 months of age and a second dose at school entry (ages 4 to 6 years). For children who were not vaccinated on schedule, providers should refer to the catch-up immunization schedule. Two doses of MMR are about 97% effective at preventing measles. One dose is about 93% effective. There is no single antigen (measles only) vaccine available in the United States. 

Adults who received at least one dose of LIVE measles-containing vaccine (which has been in use since 1968) on or after their first birthday should be protected against measles, but people in certain high-risk groups, such as health care professionals, students at colleges and universities, and those who plan to travel internationally, should have two doses or other evidence of measles immunity. 

People who were vaccinated prior to 1968 with either inactivated (killed) measles vaccine or measles vaccine of unknown type should be revaccinated with at least one dose of live, attenuated measles vaccine (MMR). A killed measles vaccine, which was available in 1963-1967, was not as effective.

Most people born before 1957 do not need to be vaccinated because they likely developed immunity to measles during childhood when the disease was widespread. However, they may need MMR vaccine or other proof of immunity if they belong to certain high-risk groups like health care workers. 

Back to top

An acute illness characterized by the following a:

• Generalized maculopapular rash lasting three or more days; AND
• Temperature 101.0°F (38.3°C) or higher; AND
• Cough, coryza, or conjunctivitis.

Back to top

Note: CDC does not request or accept reports of suspect cases, so this category is not used for national reporting.

Epidemiologic classification: Confirmed cases should be classified as internationally imported cases or U.S.-acquired cases. A detailed travel history, including dates of travel and travel destinations, are needed to classify measles cases. 

Back to top

Collection of specimens for PCR and serologic testing is recommended for patients when clinical illness, vaccination history, and exposure history indicate a high suspicion for measles. Physicians should be instructed to obtain clinical samples from suspected cases at first contact.

To minimize false-positive laboratory results, case investigation and laboratory tests should be restricted to patients most likely to have measles. Important considerations are:

• Is the patient susceptible to measles?
• Does the patient have potential exposure to measles in the past three weeks? 
  • International travel
  • Travel to an area with a measles outbreak
  • Contact with a suspected or confirmed case of measles 
• Does the patient have an illness clinically compatible with measles? 
  • Fever (greater than 101℉) AND 
  • Generalized maculopapular rash AND 
  • At least one of the "Cs" (cough, coryza, or conjunctivitis)

PCR, IgM, and IgG can all be positive in recently vaccinated people. If a person is highly suspected of having measles and they were recently vaccinated, a throat or nasopharyngeal (NP) swab should be collected for measles virus detection and genotyping at a public health lab.  

Virus detection (PCR and culture)

• The preferred specimens for PCR testing are throat or nasopharyngeal swabs (ideally collected within three days of rash onset, but up to ten days post-rash may be successful). PCR testing can also be done on urine and may improve sensitivity of testing. Clinical specimens for PCR should be collected at the same time as samples taken for serologic testing.
• Highly suspicious measles specimens should be sent to the Colorado State Public Health Laboratory for PCR testing under the direction of a CDPHE Vaccine Preventable Disease (VPD) epidemiologist. Some commercial labs also offer PCR testing for measles. A provider may choose to test low-suspicion patients commercially.
• Positive PCR in patients with an acute febrile rash illness is confirmatory unless explained by recent MMR vaccination (during the previous 6-45 days) or not otherwise ruled out by other confirmatory testing or more specific measles testing in a public health laboratory.
• Isolation of measles virus in culture is confirmatory (unless the patient was recently vaccinated), but measles culture is rarely done.
• A negative culture or negative PCR does not always rule out measles because both methods are affected by the timing of specimen collection and the quality and handling of the clinical specimens.
• Please review the Measles Testing and Specimen Collection Guidance for testing at the CDPHE lab.

Serology (IgM and IgG)

• Public health should recommend collection of a serum specimen to test for measles IgM at first report of a suspected measles patient. 
• A measles IgG antibody test is most commonly used to determine immunity to measles while measles IgM tests for acute disease.
• Measles IgG and IgM tests should both be recommended. 
• Cases with positive measles IgM results at a commercial lab may need to be retested at the Colorado State Public Health Laboratory if there is an indication the result may be a false-positive. The possibility of a false-positive IgM test is increased when: the IgM test used was not an enzyme immunoassay (EIA), the case did not meet the clinical criteria, the case is an isolated indigenous case (no epidemiologic link to another confirmed case and no international travel or travel to a place with an outbreak), the case was vaccinated within the last six months, or measles IgG was detected within seven days of rash onset.

State Laboratory testing services available:

• The Colorado State Public Health Laboratory can perform measles PCR testing on respiratory specimens or urine. Some commercial labs are able to perform measles PCR testing as well. 
• Serologic testing for measles IgM antibodies is through the Colorado State Public Health Laboratory and commercial laboratories.
• Measles IgG antibody test is available at most commercial labs and some hospital labs. It is not available at the Colorado State Public Health Laboratory. 
• Specimens for measles IgG and viral isolation may be shipped to CDC through the Colorado State Public Health Laboratory under the direction of a CDPHE VPD epidemiologist.
• The Colorado State Public Health Laboratory may charge a fee for measles testing. Testing may be provided free of charge if the specimen has been approved by a CDPHE VPD epidemiologist as part of a public health investigation.

Back to top

Local public health agencies have primary responsibility for investigating reports of suspected cases in their jurisdiction. CDPHE VPD epidemiologists are available to help local public health agencies investigate suspect cases, as needed.

Use “Questionnaire for people suspected of having measles” on the CDPHE measles webpage and the measles investigation form found on CDC’s website to help with collecting pertinent information. Information from the surveillance form should be entered into EpiTrax as soon as possible. Paper forms do not need to be faxed to CDPHE.

1. Determine whether the case’s symptoms are compatible with measles. 
   • Measles is rare in Colorado, and clinical evidence is not sufficient to confirm a case. Laboratory diagnosis is crucial to confirm the few actual measles cases among the many patients with suspected measles.
   • Gather clinical information through medical record review or by interviewing the case, the case’s guardian, and/or the case’s health care provider. Collect the following information:
     • Demographics (including address, phone number, date of birth, gender, ethnicity, and race).
     • Timing and sequence of symptoms:
       • When did the fever start? How long did it last? What was the maximum temperature? 
       • When did the rash start? Where on the body did it start? What did it look like? How did it progress? How long did it last? 
     • Were there other respiratory symptoms (cough, coryza, and conjunctivitis)?
     • Are there other possible diagnoses?
     • What lab tests are available? What is pending?
     • Has this person recently taken antibiotics or other medications?
     • Does the patient have contacts with similar symptoms?
2. Determine if the case is susceptible to measles.
   • Obtain immunization history, including MMR/MMRV vaccination dates from the medical provider, the case or case’s guardian (if conducting a patient interview), and checking the Colorado Immunization Information System (CIIS). 
   • People born in the United States  prior to 1957 probably had measles disease during childhood and are likely immune.
   • If the patient was recently vaccinated, they may have a positive PCR or IgM test result despite not having actual disease.
3. Determine if case was exposed to measles.
   • Ask if the patient traveled outside of Colorado or outside of the United States recently, including specific areas in the United States where outbreaks may be occurring.
   • Detail the patient’s activities 7-18 days prior to rash onset, including travel or visitors from other countries or other states.
   • Ask case if they had contact with other people who are ill.

4. If a suspect case is determined to have high likelihood for measles (including symptoms clinically compatible with measles, a likely exposure to measles, and is susceptible to measles):
   1. Obtain appropriate diagnostic specimens (blood and respiratory specimens) and immediately arrange testing with a CDPHE VPD epidemiologist. See Laboratory Testing Recommendations section.
   2. Establish a timeline of the patient’s activities and contacts while they were infectious (four days prior and four days after rash onset, with the day of rash onset counted as Day 0) including but not limited to:
      • Household members (significant others, children, dependents, etc.).
      • Visits to public areas like stores, restaurants, and health care facilities.
      • Attendance at school or work.
      • Social/religious/family events or gatherings.
      • Travel history (domestic or international).
      • Modes of transportation (rideshare, public transportation, personal vehicle).
      • House visitors/guests (cleaners, dog walkers, food/grocery delivery services, etc.).
      • Hospital visitors.
   3. Exclusion: 
      • People suspected or confirmed of having measles should be excluded from work, school, or child care and should voluntarily self-isolate at home until for days after rash onset (day of rash onset is counted as Day 0). 
      • In health care facilities, patients suspected of having measles should be placed in a negative pressure room. If a negative pressure room is unavailable, place the patient in a room alone with the door closed.
      • Ensure only people who are immune to measles are allowed to come in contact with the case until at least for days after rash onset.

If multiple attempts to obtain case information are unsuccessful (e.g., the case, case’s guardian, or health care provider does not return your calls, or the person refuses to divulge information), contact a CDPHE epidemiologist to discuss other options.

Back to top

Once a confirmed or highly suspect case is identified, initiate an investigation to determine who may have been exposed to the case. The main purpose of identifying contacts is to determine which contacts are susceptible to measles and to determine appropriate disease control recommendations. Identifying, notifying, and evaluating contacts may happen in a different order or simultaneously, depending on how information is received.

1. Identify contacts
   1. Using the infectious period established during the case investigation, identify settings where exposures may have occurred.
   2. Measles investigations are time-sensitive and often involve a large number of contacts, so it is recommended to focus first on people at highest risk of disease transmission. Prioritize initial contact investigation and disease control efforts on people in settings with prolonged, close proximity to the case such as households, child care facilities, schools, health care settings, travel conveyances (e.g., airplanes, trains, etc.), and congregate settings, such as churches and other institutions (colleges, prisons, etc.). 
   3. Work with the setting (i.e., the health care facility, school, child care center, etc.) to obtain a list of people who were in the same location as the case or in those areas up to two hours after the case was present and could have been exposed to measles.
2. Notify contacts 
   1. Consult with CDPHE to notify identified populations who may have been exposed to determine the most appropriate notification methods.
   2. Different forms of notification can be used in the event of a measles case or outbreak depending on the situation and urgency:
      • People who had prolonged, close contact with the case and need to be assessed for measles immunity should be contacted by phone by either public health or a health care provider.
      • A notification letter or email can be sent to school or child care classmates to notify parents/guardians and staff about measles in the community, provide vaccine recommendations, and remind parents/guardians of exclusion policies for students with a vaccine exemption.
      • Consult with the VPD unit before sending a notification letter. 
      • Hospitals or health care facilities can send a notification letter to patients who were exposed. Consult with the CDPHE VPD unit before sending a letter. 
      • A Health Alert Network (HAN) Advisory or Alert about measles can be sent to health care providers and hospitals so they are prepared to identify and test measles cases. Sending a measles HAN should be discussed with CDPHE staff who can assist you in developing and distributing the notice.
      • Social media posts and press releases are often helpful to alert the general public and provide vaccination recommendations for people who may have been exposed in places where it’s difficult to identify specific people such as grocery stores and malls. Discuss with CDPHE.
        CDPHE can post a notification on CDC’s Epi-X forum to notify other states of potential exposures in their states or request additional information on other cases.
      • Hot Topics can be used to notify the healthcare community about the current situation.
      • CDPHE will work with CDC to conduct contact notifications if a case was infectious while traveling on an airplane, train, or other similar conveyance.
3. Evaluate contacts
   1. Identified contacts should be evaluated by public health and assigned a risk category based on their likelihood of developing measles, likelihood of having severe measles disease if they develop measles, or their potential to spread to those in at-risk groups if they get measles. 
      1. High-risk contacts include people who:
         • Work in a health care setting.
         • Attends or works in a high risk setting such as an infant room of a child care facility.
         • Had close, prolonged exposure to a case such as members of the same   household, classmates, teammates, and people who sat in a doctor’s waiting room with the case.
         • Are infants <12 months old.
         • Could experience severe illness if they got measles because they are immunocompromised.
         • Are pregnant.
      2. Low-risk contacts include members of the general population who are mostly healthy and may have had passing or indirect contact with the case, such as in the same store or gym as the case.
   2. Once high-risk contacts are identified, they should be assessed to determine if they are likely to be immune to measles (See #4: Assess immunity for high- and low-risk contacts).
   3. Expand the investigation to include settings where exposure was indirect and specific people are not able to be identified such as members of the public in a store at the same time as the case.  
   4. Make disease control recommendations for people identified based on risk and susceptibility to measles as outlined in Disease Control Recommendations for Contacts section below.
4. Assess immunity of contacts
   1. People are likely immune to measles and not considered susceptible to disease if they meet one of the following criteria: 
      • One or more documented doses of live measles virus-containing vaccine administered on or after their first birthday for children and adults who are not severely immunocompromised.
      • Laboratory evidence of immunity (i.e., a positive measles IgG titer).
      • Birth before 1957. 
   2. For low-risk contacts, the following are also acceptable criteria for immunity:
      • Verbal history of disease.
      • Served in the U.S. armed forces.
      • Born in the United States in 1970 or later and attended a U.S. elementary school.
      • Entered the United States in 1996 or later with an immigrant visa or a green card.
   3. Health care workers are more likely to transmit disease to vulnerable people if they become ill, so health care workers must meet one of the two criteria below to continue working in a health care setting after a measles exposure:
      • Two documented doses of live measles virus-containing vaccine administered on or after the first birthday for children and adults who are not severely immunocompromised.
      • Laboratory evidence of immunity (i.e., a positive measles IgG titer).
   4. People who are severely immunocompromised should be considered high-risk contacts and susceptible to measles regardless of their vaccination history. This includes:
      • People with severe primary immunodeficiency;
      • Bone marrow or stem cell transplant recipients who are receiving immunosuppressive treatment or completed treatment within the past 12 months (or longer if developed graft-versus-host disease);
      • Currently receiving treatment for Acute Lymphocytic Leukemia (ALL) or who completed chemotherapy for ALL within previous six months;
      • People living with HIV with CD4 T-lymphocyte percent less than 15% (any age) or CD4 T-lymphocyte count less than 200 lymphocytes/mm3 (over 5 years old), and people who have not received MMR since starting to take antiretroviral therapy;
      • Also consider HIV-infected persons without recent confirmation of immunologic status or measles immunity;
      • People receiving daily corticosteroid therapy with a dose ≥20 mg (or >2 mg/kg/day for patients who weigh <10 kg) of prednisone or equivalent for ≥14 days; and
      • People receiving certain immunomodulatory medications (e.g., tumor necrosis factor-alpha [TNF-α] blockers).

Back to top

People identified as likely to be immune or NOT susceptible to measles should watch for measles symptoms for 21 days after last exposure and contact public health if they think they are developing measles.

Disease control recommendations for people identified as susceptible to measles is based on whether or not the contact is considered high or low risk.  

Disease control recommendations for susceptible contacts
 

HIGH-RISK CONTACTS

LOW-RISK CONTACTS

1. For healthy infants aged 6-11 months, MMR vaccine is preferred to IG if the exposure to measles occurred within 72 hours. MMR doses for children <12 months are for immediate protection against a measles exposure and do not count towards vaccine recommendations. IG is recommended for infants <6 months. 

2. IG should be administered within six days of exposure and can extend the incubation period for measles. Monitor contacts who received IG for 28 days after last exposure to the case. 

3. Exclude from high-risk settings (health care facilities, child care facilities) from Day 7 (Day 5 for health care workers) after first exposure through Day 21 after last exposure until they are able to provide proof of immunity to measles.

4. Exclude from high-risk settings if MMR is given >72 hours after exposure or IG is given >6 days of first exposure. 

5. If it can be done rapidly, recommend that people who are pregnant be tested for measles IgG prior to receiving IGIV if there is a possibility they received a vaccine or had disease. Administer IGIV if patient is IgG negative, or has unknown status and testing cannot be completed by Day 6 after exposure. 

6. There is no public health recommendation for IGIM administration in susceptible people >30 kg (66 lbs). If patient is >6 months, MMR PEP is preferred if within 72 hours of exposure. 

7. If implemented, quarantine should last from Day 7 after first exposure through Day 21 after last exposure unless the exposed person meets a presumption of immunity or receives PEP within the appropriate timeframe.

1. Post-exposure prophylaxis (PEP)
   1. Post-exposure vaccination (MMR)
      • MMR vaccine is recommended for people exposed to measles who do not have evidence of measles immunity and for whom vaccination is not contraindicated.
      • Administration of MMR vaccine to susceptible contacts of a measles case may abort infection or modify the disease if given within 72 hours of the first exposure.
      • MMR vaccination of non-immune contacts may be recommended beyond 72 hours post-exposure to provide protection from future exposures, especially if there is ongoing transmission in a particular setting such as a child care, school, or work setting.
      • MMR vaccine should not be given within six months to people who received intramuscular immune globulin (IMIG) or within eight months to people who received intravenous immune globulin (IVIG).
      • In some studies, MMR PEP effectiveness is low (even though protection against future exposures is high) and likely depends upon the nature of the exposure, among other things. Therefore, exposed people who received appropriate MMR PEP should still be excluded from high-risk settings, educated to watch for measles symptoms, and call public health if they develop symptoms of measles.
      • While the public health response to sporadic measles cases should focus on those who are completely unvaccinated and more likely to be susceptible, in certain settings and if resources are available, it may be appropriate for people with one dose of MMR to get a second dose as post-exposure prophylaxis.  
   2. Immune globulin (IG)
      • IG can be given intramuscularly (IMIG) or intravenously (IVIG) within six days of exposure to prevent or modify infection.
      • For most contacts, post-exposure MMR vaccination is preferable to IG.
      • IMIG is available through CDPHE and recommended for unvaccinated, exposed infants and children <30kg/66lbs who can’t get MMR. Dosage is 0.5mL/kg (max 15 mL). Persons weighing >30 kg/66 lbs are unlikely to receive an adequate amount of measles antibody from IMIG so IVIG should be considered.
      • IVIG is recommended for exposed, unvaccinated adults who cannot get MMR (such as pregnant people) and those who are severely immunocompromised. It is typically maintained by hospitals and administered in health care facilities.
      • Neither IMIG or IVIG are indicated for household or other close contacts who received one dose of vaccine at 6 months or older unless they are immunocompromised.
      • People who received IMIG or IVIG should not receive MMR vaccine within six months of receiving IMIG or within eight months of receiving IVIG.
      • IMIG and IVIG can extend the incubation period for measles; monitor contacts who received IG for 28 days after last exposure to the case.
        • IMIG is available in 2 ml and 10 mL single dose vials. IG is costly and has a relatively short shelf life. CDPHE-supplied IMIG may only be used for post-exposure prophylaxis.
        • CDPHE maintains IMIG at two locations (one CDPHE location, one LPHA location). CDPHE is using a shared spreadsheet to track IG across the state; all LPHAs who receive IG for a response are expected to use this spreadsheet. To request IG please call the Communicable Disease Branch at 303-692-2700 (after hours 303-370-9395) or email cdphe_vpd@state.co.us. IG available through CDPHE is a state-purchased asset. In order for CDPHE to release IG, LPHAs must provide information about the planned use. 
2. Exclusion
   • Contacts of measles cases may be excluded from work, school, or child care if they do not meet appropriate immunity status. Exclusion may be used independently of quarantine.
3. Symptom watch
   • Active or passive symptom watch may be recommended for people exposed to measles who are at low risk for developing and spreading disease.
   • Active symptom watch:
     • Public health communicates with the contact daily during the incubation period and asks about symptoms consistent with measles, particularly fever and respiratory symptoms. 
   • Passive symptom watch:
     • Public health educates the contact on signs and symptoms of measles and provides a phone number for the contact to use if he/she develops symptoms.
     • If there is concern about the contact not reporting symptoms, active symptom watch may be recommended.
   • If contacts develop symptoms during symptom watch, instruct them to call their doctor’s office before seeking care and to wear a mask around people, especially if they will be going to a health care facility.
4. Quarantine
   • Quarantine is a process in which public health requires a person considered to be susceptible and who was exposed to measles stay in their home until 21 days after their last exposure to measles.  
   • Quarantine can be a verbal agreement or a letter that outlines what should be done, but if there are concerns for compliance, a public health order should be issued.
   • Contact CDPHE VPD epidemiologists before placing a person in quarantine. Imposing quarantine measures is both difficult and disruptive, but may be necessary for disease control. 
   • A quarantine letter template is available upon request. Contact the VPD unit directly for a copy. 
     • The quarantine template is not intended as, nor should it be construed as, legal advice. Rather, it is meant to assist those preparing to issue an order of quarantine to think about the types of issues that one might address in such an order. Seek professional legal guidance prior to finalizing any public health order. 
   • CDPHE and LPHAs both have authority to issue quarantine orders.
   • Consider arranging resources for quarantined people to help with compliance. This could include food delivery, job assistance, etc. Ensure only people who are immune to measles come in contact with the person in quarantine.  
   • People under quarantine should be regularly contacted by public health to monitor for development of measles symptoms. 
5. Isolation
   • Isolation is the separation of sick people from well people.
   • If someone develops symptoms consistent with measles, they should remain isolated at home or in a health care facility until they are no longer contagious.
6. Environmental measures
   • If a person infected with measles is examined in a health care facility, the examination room they used should be closed for two hours afterwards and undergo routine cleaning by someone who has documented immunity to measles.

Back to top

1. Incident Command System (ICS)
   • Incident Command System (ICS) may be activated to manage a measles outbreak when normal work capacity is exceeded. For example:
     • The outbreak is spread across multiple counties and/or across state borders.
     • The affected LPHA does not have enough resources to respond appropriately.
   • CDPHE Office of Emergency Preparedness and Response (OEPR) is available to help with implementing and coordinating ICS if requested by LPHA.
2. Emergency preparedness and response functions
   OEPR and LPHA EPR may provide assistance during an outbreak response depending on the needs of the organization or jurisdiction. Some assistance or responsibilities may include, but not limited to:
   • Activate Colorado’s emergency hotline (COHELP) to receive calls from the public.
   • Distribute HANs. 
   • Coordinate press releases.
   • Coordinate conference calls and meetings with partners.
   • Assist with data entry and management.
   • Distributing and implementing isolation and quarantine orders.
   • Assist with vaccine and PEP coordination and management.
   • Coordinate vaccine clinics.
   • Interview cases and contacts.
   • Coordinate language services.

Back to top

Outbreaks

• A measles outbreak is defined as a chain of transmission including three or more cases linked in time and space. 
• The primary strategy for control of measles outbreaks is achieving a high level of immunity (i.e., two doses of measles vaccine) in the population affected by the outbreak. 
• During an outbreak:
  • MMR vaccine may be given to infants as young as 6 months old. Children immunized before their first birthday should still be immunized with MMR/MMRV vaccine at 12 to 15 months (at least four weeks after the initial measles immunization) and again at aged 4 - 6 years as seroconversion rates are significantly lower in those immunized before their first birthday.
  • People who cannot readily document measles immunity should be vaccinated or excluded from the affected setting (school, hospital, child care). In an outbreak setting, only doses of vaccine with written documentation of the date of receipt should be accepted as valid. 
  • There may be additional recommendations for people with one valid dose of MMR vaccine to receive a second dose of MMR as long as it’s been 28 days after their first dose. Please discuss with state and local immunization programs. 
  • During an outbreak, public health might also recommend people with one dose of MMR get a second dose as post-exposure prophylaxis. 
  • Verbal reports of vaccination without written documentation should not be accepted during an outbreak. People who have been exempted from measles vaccination for medical, religious, or other reasons should be excluded from affected institutions until 21 days after the onset of rash in the last measles case.
  • Under special circumstances, such as during outbreaks in schools attended by large numbers of people who are not vaccinated, restricting social events such as school dances, athletic events, and conferences might be warranted. 
• A diagnosis of measles and measles testing should be highly considered in people with measles-compatible symptoms (rash and fever) in the outbreak-affected area. 
• Intensify surveillance by providing measles information to hospitals, emergency rooms, urgent care clinics, physicians, schools, and day care providers.

Health care facilities

People who work in health care settings (including volunteers, trainees, nurses, physicians, technicians, receptionists, and other clerical and support staff) are at increased risk of exposure to measles and at increased risk of transmission to people at high risk of severe measles. For this reason, health care workers have different criteria for presumptive evidence of immunity. 

1. Health care workers need to meet one of these criteria:
   • Documentation of a positive measles IgG test.
   • Documentation of two doses of measles-containing vaccine given in 1968 or later, separated by at least 28 days, with the first dose on or after the first birthday.
2. Disease control recommendations for health care settings:
   1. Establish a point of contact at the health care facility (preferably the infection preventionist) who will gather information needed for investigation and disease control, such as lists of exposed health care workers and patients and their immunity statuses.
   2. Create a timeline of the case’s movement within a health care facility. Determine what time the patient was in the waiting room, what time they were moved to an exam room, moved to a negative pressure room, or moved to other areas of the health care facility (such as the cafeteria, lab, x-ray, etc.). This information is used to determine who was exposed (staff and patients).
   3. As measles virus can spread through HVAC systems, it may be helpful to request a map of the facility and HVAC information to determine patient areas where the virus could have traveled. 
   4. Determine who will contact patients who were exposed to measles, whether it will be the health care facility or public health, and how the contacts will be notified (e.g., certified letter, phone call, etc.). Public health should provide a notification letter or work with the health care facility to develop the letter.
   5. Typically, patients who were in close proximity to the case (emergency department, waiting room, etc.) should be contacted by phone, especially if it is within the window to receive PEP (72 hours for vaccine, or 6 days for IG for individuals where IG PEP is recommended). For patients with minimal exposure (such as sharing a hospital floor, but on a different wing), a letter is usually adequate.
3. Health care worker exclusion:
   • Health care personnel meeting the following criteria may continue to work but should be instructed to watch for symptoms and contact employee health if they develop symptoms. 
     • Documentation of a positive measles IgG test. 
     • Documentation of two doses of measles-containing vaccine given in 1968 or later, separated by at least 28 days, with the first dose on or after the first birthday.
   • Susceptible health care workers who do not meet the above criteria and are exposed to measles should be relieved from patient contact and excluded from the facility from Day 5 to Day 21 after exposure or until the facility is declared measles-free, regardless of whether they received vaccine or immune globulin after the exposure.
   • Health care workers with one documented previous MMR and unknown IgG should receive an additional dose of MMR. Alternate work arrangements should be made to avoid direct patient care and monitor symptoms through the 21st day after the last exposure. 
     Instruct health care workers to immediately report any symptoms consistent with measles.
   • Health care personnel who develop measles should be excluded from work and may not return to the facility until 7 days after rash onset due to their high-risk occupation.
   • Health care personnel with documentation of a positive measles IgG test or documentation of two doses of measles-containing vaccine given in 1968 or later, separated by at least 28 days, with the first dose on or after the first birthday may continue to work but should be instructed to watch for symptoms and contact employee health if they get sick.
4. Patients
   • Patients who are diagnosed with measles while hospitalized should be isolated using airborne and contact precautions for four days after rash onset (with date of rash onset counted as Day 0).
   • Immunocompromised patients should be isolated for the duration of their illness because they may shed measles virus for extended periods.
   • Exposed, susceptible patients should receive MMR vaccine within 72 hours of exposure, if possible, and if vaccination is not contraindicated.  IG may be recommended for some patients.
   • All exposed susceptible patients should be discharged as soon as possible and advised to continue to watch for measles symptoms for 21 days after discharge or last exposure date.
   • All susceptible, exposed patients (including those receiving their first MMR vaccine dose within 72 hours of exposure) unable to be discharged should be placed in airborne and contact precautions from Day 5 to Day 21 after exposure.
   • Hospitalized measles cases should be attended to and visited by only people who are immune to measles.

Child care and preschools

Refer child care providers to the CDPHE guidelines, “Infectious disease guidelines in child care and school settings” for additional measles information.

• Determine the dates the measles case attended child care or preschool while infectious. 
• Child care staff and/or public health personnel should review the measles vaccination records of all children and staff at the facility to determine who at the facility is susceptible to measles.
• Only doses of vaccine with written documentation of the date of receipt should be accepted as valid. Verbal reports of vaccination without written documentation should not be accepted.
• Children and staff who cannot readily document measles immunity should be vaccinated within 72 hours of exposure (if not contraindicated) or excluded from the setting for 21 days after last exposure. IG may be recommended for some people.

Exclusion

• Measles cases should be excluded from child care and isolated at home for four days after rash onset (day of rash onset is counted as Day 0). 
• People who have been exempted from measles vaccination for medical, or non-medical reasons should be excluded from affected facilities in the outbreak until 21 days after the onset of rash in the last measles case.

Notifications

• Recommend that the child care center or preschool notify parents/guardians/caregivers, staff, and anyone entering the facility of the possible exposure to measles. CDPHE or the local public health agency can provide a sample letter for distribution.
• Child care and preschool personnel should report all suspected measles cases to CDPHE or their local public health agency.

Schools and colleges

Refer school personnel to the “Infectious disease guidelines in child care and school settings.”

• Determine the dates the measles case attended school while infectious, and if they’re a college student, what classes they attended.
• School and/or public health personnel should assess the immunity of students and staff directly exposed to a measles case in classrooms, dorm rooms, and other shared spaces by reviewing measles immunization records. If possible, schools and colleges should provide a list of students and staff exempt from vaccination to public health.  
• In schools and colleges with a measles outbreak, people who are not immune to measles should be vaccinated or excluded. This includes all students and all school personnel born during or after 1957, who cannot provide documentation that they received at least one dose of measles-containing vaccine on or after their first birthday or cannot provide other evidence of measles immunity (such as serologic testing).

Exclusion

• Measles cases should be excluded from school or college classes and isolate themselves at home during their infectious period (through four days after rash onset).
• If a measles exposure occurs within a school, all susceptible students including exempted students and staff refusing measles-containing vaccine or lacking proof of immunity to measles will be excluded from school until the outbreak is over (e.g., until 21 days after the onset of rash in the last reported case). 
• People receiving a second dose may be immediately re-admitted to school. 
• Previously unvaccinated people who receive an MMR/MMRV vaccine as post-exposure prophylaxis within 72 hours of their exposure may be immediately re-admitted to school.  
• Because it takes time to develop immunity following vaccination, unvaccinated people exposed to someone with measles who are vaccinated outside of the 72-hour window should remain excluded from school for the duration of their incubation period. However, public health may consider re-admitting unvaccinated students at the time of vaccination if exposures are widespread and allowing these students back at school increases overall vaccination coverage and school productivity.

Notification

• Recommend school personnel notify students, parents/guardians/caregivers, and staff about a possible measles exposure. CDPHE or the local public health agency can provide a sample letter.
• School personnel should report all suspect measles cases to CDPHE or their local public health agency.

Jails and detention centers

• Measles cases should be isolated from other people who are incarcerated or detained,  and susceptible personnel for four days after rash onset (day of rash onset is counted as Day 0).
• Determine dates the measles case was infectious and identify exposed people who are incarcerated or detained, staff, and visitors.
• Determine the measles immunity status of exposed personnel and people who are incarcerated or detained.
• Provide MMR immunization to susceptible personnel and people who are incarcerated or detained within 72 hours of exposure, if possible, and if vaccination is not contraindicated.
• Immune globulin should be administered to exposed susceptible inmates and staff at increased risk of developing measles complications following recommendations in the Red Book.

Airlines

• Measles cases should not travel by airplane until four days after rash onset (day of rash onset is counted as Day 0).
• For measles cases who report airline travel while infectious, obtain detailed flight information including flight numbers, airline, date and time of travel, seat number, and who the case sat next to (i.e., their family member, a friend, or a stranger).
• CDPHE will notify the CDC Quarantine Station to investigate and follow up on measles cases on domestic and international flights. Notify a CDPHE VPD epidemiologist if a measles case was on a flight while infectious.

Back to top

Specimen collection instructions, questionnaires for suspect cases, tools to help determine susceptibility to measles, and other resources to use during an investigation are available on CDPHE’s measles webpage:https://cdphe.colorado.gov/diseases-a-to-z/measles

CDC’s guidelines for measles PCR, virus isolation, and serology are available at the following link:
https://www.cdc.gov/measles/php/laboratories/?CDC_AAref_Val=https://www.cdc.gov/measles/lab-tools/rt-pcr.html 

Back to top

American Academy of Pediatrics (Red Book). Measles. Red Book 2024-2027: Report of the Committee on Infectious Diseases, 33rd Edition.  Illinois, American Academy of Pediatrics, 2024.

CDC. Epidemiology and Prevention of Vaccine-Preventable Diseases. Hamborsky J, Kroger A., Atkinson W,  Wolfe S, eds. 14th ed. Washington DC: Public Health Foundation, 2021 or https://www.cdc.gov/vaccines/pubs/pinkbook/index.html.

Centers for Disease Control and Prevention. Manual for the surveillance of vaccine-preventable diseases. Centers for Disease Control and Prevention, Atlanta, GA, 2019. 

CDC. Measles- United States, January 1, 2020 - March 28,2024. MMWR, April 11, 2024; 73(14); 295-300

Centers for Disease Control and Prevention. National Notifiable Diseases Surveillance System. 2013 Measles Case Definition. January 2013. Accessed on-line January 2013. 

Back to top