Classroom

B73 Measles

Key Facts

Page Updated 4-2-26


  • Agent: Measles (rubeola) virus
  • Reservoir/Source: Human/Respiratory tract secretions and fomites.
  • Symptoms: Consider measles in patients of any age who have a fever ≥101°F, plus at least one of the 3 “Cs” (cough, coryza, or conjunctivitis) and a descending rash that starts on the face. The rash typically follows the onset of illness within 4 days. Atypical and modified rash can start on trunk and/or limbs.
  • Complications: Diarrhea, otitis media, pneumonia, encephalitis, subacute sclerosing panencephalitis, acute disseminated encephalomyelitis, keratitis, myocarditis, pericarditis, and death.
  • Differential Diagnoses: Kawasaki disease, rubella, scarlet fever, Fifth's disease, enteroviruses, and other febrile rash exanthems.
  • Incubation: From exposure to rash onset, 7-21 days with an average of 14 days.
  • Communicability and Transmission: From 4 days before rash onset date to 4 days after rash onset date via direct contact with infectious droplets or by airborne spread.
  • Presumption of Immunity Criteria: See Box 2.
  • Specimen Collection/Lab Testing: Throat or nasopharyngeal (NP) swab, urine, and serum, see Box 1 for details.
  • Specific Treatment: Supportive care only; antiviral agent not available. Vitamin A supplementation may be beneficial for reducing measles severity and risk of complications.
  • Post-Exposure Prophylaxis: MMR or immune-globulin/intramuscular immune globulin (IMIG). See Investigation of Asymptomatic Contacts to a Measles Case for more details.
  • Recommended Vaccines: MMR and MMRV
  • Reportable Criteria: Report by phone immediately upon suspicion of measles: 213-351-7800 weekdays 8:30am-5:00pm, or 213-974-1234 (option 8) after hours.
    Do not wait for laboratory confirmation before reporting.
Investigation of a Suspect Measles Case
1. Measles Report Notification

Reportable: California Code of Regulations, Title 17, Section 2500. All providers must report suspect measles cases immediately by phone to the LA County Department of Public Health’s Vaccine Preventable Disease Control (VPDC) Program at 213-351-7800 weekdays 8:30 am to 5:00 pm, or 213-974-1234 (option 8) after hours. Do not wait for laboratory confirmation before reporting.

  1. If the Health District received an initial measles report, the Health District must immediately call VPDC’s main line at 213-351-7800, ask to speak to the investigator on duty, and notify VPDC of the case.
  2. Within 24 hours of notification, VPDC will conduct the initial assessment of the case.
  3. If Health District follow-up is needed, VPDC will open the incident in IRIS, route to the Health District of case’s residence, and notify Health District leadership.
2. Establish Communication with Case
  1. If field support is needed, Health District commences investigation within 24 hours of case notification and completes steps B through F.
  2. Obtain all documents from the reporting facility and the IRIS filing cabinet and read IRIS notes provided by the VPDC initial investigator, if available.
  3. Conduct case interview to complete Initial Assessment Form, if not yet completed. This can be done over the phone.
  4. If unable to reach the case by phone and case interview has not been completed, at least one home visit is required within 24 hours of receipt of case assignment. After 3 unsuccessful attempts within 24 hours, a second home visit is required within 48 hours of receipt of assignment.
  5. If all contact attempts are unsuccessful within 48 hours of receipt of assignment, consult with Public Health Nurse (PHN) Supervisor and Regional Medical Director (RMD) for immediate referral to PHI.
  6. At any point in the investigation, if the case becomes non-compliant with instructions to submit requested information or adherence to isolation procedures, consult with PHN Supervisor and RMD immediately. CFS will serve Isolation Health Officer Order within 24 hours of knowledge of non-compliance.
3. Clinical Assessment of Case
  1. VPDC, or the Health District if triaged for field support, will review medical notes, Initial Assessment Form, and any other documentation in IRIS filing cabinet and notes/remarks to confirm the following:
    1. Fever onset date and duration
    2. Rash onset date and duration
    3. Onset date and duration of “3 C’s” – cough, coryza, and/or conjunctivitis
    4. Immunocompromised status (current and and at time of exposure)
  2. Determine from case and evaluating clinician if case had any of the following:
    1. An MMR vaccine within 45 days of illness onset date (document the number of doses and dates for all MMR vaccines received)
    2. Immune-globulin within the last year (document date)
    3. Antibiotics within the last 4 weeks (document antibiotic name, dosage, indication, treatment start date, and completion date)
4. Specimen Collection: Urine, Throat or NP, and Serum
  1. Consultation and pre-approval is required by Vaccine Preventable Disease Control (VPDC) for measles laboratory testing – call VPDC at 213-351-7800 from 8:30 am to 5:00 pm Monday to Friday, or 213-974-1234 (option 8) after hours.
  2. See Box 1 for step-by-step instructions on specimen collection.
  3. The staff member(s) collecting specimens must have documented measles immunity (two documented MMRs or a positive measles IgG titer).
  4. Specimen collection can occur at Public Health Centers or elsewhere (such as a private provider's office or the case’s home). When possible, choose a setting that minimizes exposing other patients to the case. Ideally, schedule the case to come into the clinic at the start or end of the day.
  5. Suspect measles cases should wear a high-grade medical mask and immediately be escorted to an airborne isolation room away from other patients. If an airborne isolation room is not available, a private room can be used. Otherwise, consider collecting the specimen outdoors, such as at the patient’s car.
  6. Do not use the exam room again until one hour after the case has left the room.
  7. Immediately notify VPDC of specimens collected by emailing vpdc@ph.lacounty.gov or calling 213-351-7800 and asking for the investigator on duty.
5. Case Isolation
  1. VPDC, or the Health District if triaged for field support, must isolate the case based on the following categories:
    • Febrile rash: Regardless of measles immunity status, the case should not attend school, participate in any social activities, use public transit, or attend public gatherings or venues until Public Health has determined that the case does not have measles.
    • Confirmed Measles: Regardless of immunity status, the case must isolate until the end of the 4th day after rash onset.
    • Hospitalized Case: Prompt airborne isolation is required until the end of the 4th day after rash onset. If case is immunocompromised, airborne isolation should be maintained throughout illness duration.
  2. VPDC, or the Health District if triaged for field support, sends a Measles Case Isolation Letter to confirmed case on the same day that initial contact is made.
  3. An Off Work Notice may be considered to enforce exclusion from work. Consult PHN Supervisor and Regional Medical Director (RMD) if other institutional exposure isolation procedures, such as an Isolation Health Officer Order, is being considered.
6. Identify Exposed Contacts
  1. Determine dates of contagious period: 4 days before rash onset through 4 days after rash onset. Rash onset date is day 0.
  2. Exposure Definition: Anyone who shared the same airspace with case OR was present in the same airspace within 1 hour after the case left is considered exposed. In large community sites in a low-risk setting (e.g. airport, grocery store), direct contact investigation by DPH may be limited to those with close face to face contact (<6 feet).
  3. Identify sites where the case visited while contagious. Use credit card receipts, calendars, and other tools to try to get a complete list of sites.
    1. The Measles Activity Log is an optional tool to help identify sites. The investigator may provide the log pre-filled with dates of the contagious period and ask the case to fill it out.
  4. Once all possible contacts have been identified and a measles diagnosis has been confirmed in consultation with VPDC, proceed to the section Investigation of Asymptomatic Contacts to a Measles Case below.
Investigation of Asymptomatic Contacts to a Measles Case
1. Obtain line lists from Exposure Sites
  1. Within 24 hours of case interview, VPDC will assign exposure sites based on location type to programs.
    1. Community Exposure Sites (e.g. grocery stores, restaurants, amusement parks, etc.): Health District
      1. Consider issuing Health Officer Order to communicate expectations effectively.
      2. Ask site(s) to post Exposure Notification Flyer (available in English, Spanish, Chinese Simplified, Traditional Chinese, Armenian, Russian and Vietnamese) for the duration of the surveillance period (21 days after the most recent date of exposure).
      3. Provide a Facility Exposure Notification Letter (available in English and Spanish) to exposure site(s). Consistent with language in this letter, facility should be instructed to:
        1. Share General Exposure Notification Letter After Confirmed Measles Case (available in English and Spanish) with all staff members who may have been exposed.
        2. Identify all high-risk individuals known by facility (e.g. pregnant without at least 1 MMR dose or positive IgG, severely immunocompromised per Box 3) for priority outreach.
        3. Instruct staff to monitor for measles symptoms. Should exposed contacts develop symptoms, require staff to stay home and contact DPH.
        4. Instruct staff that DPH will contact them to evaluate their immune status. Facility should inform employees/staff to cooperate to avoid unnecessary exclusion or quarantine.
      4. Any individual identified to have face-to-face contact <6 feet from the index case by either the facility or by the case should be listed on the Measles Line List for further evaluation of immune status by DPH. Send line list to vpdc@ph.lacounty.gov.
    2. Healthcare Facilities (HCF), including exposed staff and patients:
      ACDC Healthcare Outreach Unit (HOU). HOU should give HCF a copy of the CDPH Healthcare Exposure Investigation Quicksheet and make HCF aware that they will be responsible to:
      1. Assign a team to serve as points of contact with ACDC throughout investigation.
      2. Fill out line list of exposed healthcare personnel (HCP) and patients, plus any parents/guardians who accompanied minor patients, using the Healthcare Measles Line list. Send to vpdc@ph.lacounty.gov.
        1. NOTE: Once line list has been provided to HOU and VPDC, any patients and accompanying parents/guardians who have not been successfully contacted or cleared by HCF by a time agreed upon between all parties should be entered into IRIS by VPDC and assigned to the Health District for follow-up.
      3. Assess immunity for all HCP (see Table 2 for Measles Contacts Who Work in a High-Risk Setting) and quarantine and/or exclude if not immune.
      4. Identify all severely immunocompromised (see Box 3 for criteria) and pregnant patients and share information with ACDC HOU.
      5. Send Provider Exposure Notification Letter for Individuals Exposed to Measles (available in English and Spanish) to all patients regarding their exposure via patient portals, email, or mail. HCF should instruct patients that DPH may contact them and to cooperate to avoid unnecessary exclusion or quarantine.
      6. Establish and implement a protocol and/or a pop-up clinic for exposed and eligible patients and staff to receive IgG titers, MMR, IMIG, and/or IVIG (see Figure 2 for Immune Globulin Dosage for Measles Exposure).
      7. Provide regular updates on contact made and cleared status of staff, patients, and other patrons exposed.
    3. Flight Exposure: Health District
      1. VPDC coordinates with CDC and CDPH for line list. List will be distributed to CFS investigators within 1 business day unless there are high-risk contacts identified. If high-risk contacts are identified, outreach should occur within 24 hours.
      2. At end of investigation, CFS will complete Outcome Reporting Form from CDC and email to vpdc@ph.lacounty.gov. VPDC will review and email Outcome Reporting Form to CDPH via vpdreport@cdph.gov. CDPH then sends to CDC.
    4. Schools: Health District
      1. Within 24 hours of initial communication, the assigned investigator will also provide a Facility Exposure Notification Letter (available in English and Spanish) to school. School staff should be instructed to:
        1. Share Exposure Notification for Individuals Exposed to Measles (available in English and Spanish) with all staff and students who may have been exposed.
        2. Identify all high-risk individuals known by school (e.g. pregnant without at least 1 MMR dose or positive IgG, severely immunocompromised) to prioritize outreach.
        3. Complete a Measles Line List of all exposed staff and students and send to vpdc@ph.lacounty.gov.
        4. Provide immunization records for exposed students and staff.
        5. Instruct staff and students that DPH will call them to evaluate their immune status. School should inform staff and families to cooperate to avoid unnecessary exclusion or quarantine.
  2. Once line lists have been received, VPDC will create contact investigation records in IRIS for follow-up by the Health District of residence (excluding healthcare facility staff and patients managed by ACDC HOU). NOTE: In some instances, a different SPA may be managing contacts; if so, VPDC will need to select a Health District that corresponds to the SPA that’s managing follow-up under the Investigation tab in IRIS.
    1. Completed line lists should be sent via secure email to VPDC at vpdc@ph.lacounty.gov.
    2. If a line list is not received within 48 hours:
      From a Community Site: VPDC will request a site visit from CFS PHN or Environmental Health to obtain a completed line list.
      From a Healthcare Facility: ACDC HOU may escalate request to Chief Medical Officer or conduct a site visit.
  3. Throughout the investigation, the assigned investigator will provide their assigned sites with a daily list of individuals to exclude. VPDC will generate this list for distribution as needed.
  4. If an exposure site becomes non-compliant at any point in the investigation, consult with PHN Supervisor and RMD to determine whether a Health Officer Order is warranted (if not already served).
2. Establish Communication with Contact and Confirm Exposure
  1. Within 24 hours of assignment, the assigned investigator attempts to interview the contact.
    1. The assigned investigator should attempt to reach the contact at least once per 24 hours (for up to 72 hours) until contact is interviewed. If contact is not reached by phone, a home visit should be attempted within 48 hours. If contact is not reached after home visit attempt, consult with PHN Supervisor and RMD for immediate referral to PHI to obtain additional contact information. After at least 3 unsuccessful contact attempts (including at least 1 home visit attempt) or if surveillance period has ended without response, record as lost to follow up.
    2. If contact has not responded after 24 hours of initial contact attempt, the exposure site will be informed to exclude the individual from the site by the site's assigned point of contact (see section Obtain Line Lists from Exposure Sites).
  2. The assigned investigator interviews contact to determine the following critical information, using the Measles Contact Interview Form if needed:
    1. Exposure setting
    2. Risk level (high or low)
    3. Measles immunity status
    4. Contact with persons at high risk of severe illness
    5. Signs and symptoms
  3. After the interview, the assigned investigator sends contact the Exposed Individual Notification Letter with guidance on actions they will need to take until the end of the surveillance period.
  4. If a contact is in a jurisdiction other than LA County:
    1. Lives in or is Visiting Another Jurisdiction in the U.S.: Mark as “Resides Out of Jurisdiction (OOJ)” under Interview Status in IRIS. Email VPDC@ph.lacounty.gov with all available information. VPDC will then notify CDPH at vpdreport@cdph.gov and CDPH will then route to the proper jurisdiction. If the other jurisdiction is the contact’s permanent address, VPDC will then close the record as false.
    2. Lives in or is Visiting a Jurisdiction Outside the U.S.: Mark “Resides Out of Jurisdiction (OOJ)” under Interview Status in IRIS. Email VPDC@ph.lacounty.gov with all available information. VPDC will then notify CDC at measlesreport@cdc.gov so they can issue a Foreign Public Health Notification.
3. Specimen Collection for Symptomatic Contacts
  1. If a contact reports symptoms at any point of the investigation, immediately notify VPDC by calling the VPDC main line at 213-351-7800 and ask to speak with the investigator on duty, or email vpdc@ph.lacounty.gov.
  2. Immediately coordinate specimen collection for testing. See Box 1 for collection equipment and guidelines.
  3. Begin steps in Investigation of a Suspect Measles Case.
4. Determine Risk Level
  1. High-risk contacts are those who may experience severe illness if infected or to/from whom transmission potential is high.
    Examples of high-risk individuals:
    • Pregnant people without at least 1 MMR or a positive IgG test
    • Infants <12 months of age
    • Severely immunocompromised persons (see Box 3)
    • Household contacts
    • Persons with prolonged exposure (e.g., rideshare driver of the case)
    • Persons who work in high-risk settings. High-risk settings include locations in which transmission risk is high (e.g., setting with a large number of measles susceptible persons or an infant care setting). Healthcare contacts who are not healthcare workers and are not otherwise high risk can be followed up as low risk.
  2. Low-risk contacts are those who are not at high risk of experiencing severe illness or to/from whom transmission potential is not high.
    Examples of low-risk individuals:
    • Immunocompetent
    • ≥12 months of age
    • Not pregnant
    • Not a healthcare worker
    • Not a household contact
5. Determine Immune Status
  1. High-risk contacts who self-report measles immunity have 24 hours from initial interview to produce evidence of immunity (see Box 2).
  2. Low-risk contacts have 48 hours from initial interview to meet presumptive immunity criteria (see Box 2).
  3. If immunity criteria are not met within specified time frame, the investigator will attempt to collect specimen for IgG titers. An attempt to collect specimen for IgG titers should occur within 24 hours for high-risk contacts and within one business day for low-risk contacts. Contacts should be advised to quarantine while IgG results are pending. Contacts may also go to their private healthcare providers for IgG titers if they prefer.
  4. If IgG titer result is negative, the assigned investigator should offer MMR to contact.
  5. If contact refuses IgG blood draw and does not produce evidence of immunity, the investigator should provide the contact with quarantine and/or exclusion guidance and symptom monitoring (see section Quarantine/Exclusion from High-Risk Settings).
6. Post-Exposure Prophylaxis (PEP)
  1. The administration of MMR vs. immune globulin (IG) for PEP depends upon time since exposure to case, age, and risk level. See Figure 1 for more details.
    MMR is acceptable PEP when all the following criteria are met:
    • <72 hours have passed since first exposure to case
    • ≥6 months of age (though IG is preferred for infants 6-11 months)
    • 1 or no documented MMR vaccines or negative IgG

    Immune Globulin (IG) is acceptable PEP when the following criteria are met:

    • ≤6 days have passed since first date of exposure to case (can be given ≤6 days from last date of exposure to reduce risk of infection but this is not considered adequate PEP for contact management)
    • Susceptible persons not eligible for MMR or immunocompromised persons regardless of immune status
  2. The assigned investigator will recommend PEP for eligible contacts and coordinate with DPH Clinic Services to offer PEP at a Health Center for those unable to receive it through their healthcare providers. Health District staff should follow the IMIG Clinic Services protocol (DPH Only) if administering IMIG.
  3. A contact who receives PEP may discontinue quarantine but must still be excluded from high-risk settings (e.g., healthcare settings, infant daycare) for 21 days after most recent date of exposure.
7. Quarantine/Exclusion from High-Risk Settings
  1. Quarantine refers to staying at home and not sharing airspace with people susceptible to measles. Exclusion refers to staying out of high-risk settings and can apply to persons who are not otherwise quarantined. See appendix for more details on quarantine and exclusion by contact risk level.
  2. If contact does not meet immunity criteria (Box 2) within allotted time frame (24 hours for high risk and 48 hours for low risk), the assigned investigator will provide quarantine guidance and, if applicable, exclusion guidance.
    • An Off Work Notice (DPH Only) may be sent to enforce exclusion from work.
    • High-risk contacts may be released from quarantine if they receive adequate PEP or provide evidence of immunity. However, they still must be excluded from high-risk settings.
  3. Low-risk contacts who work in or attend a high-risk setting and have only 1 documented MMR dose or meets other low risk presumption of immunity (see Box 2) do not require quarantine but require exclusion from the high-risk setting. If they do not have at least 1 documented dose of MMR and do not meet presumption of immunity, they require both quarantine and exclusion.
    • An Off Work Notice (DPH Only) may be sent to enforce exclusion from work.
  4. Contacts who receive IG PEP should be excluded from high-risk settings for 28 days after last exposure.
  5. If a contact is non-compliant, consult with PHN Supervisor and RMD to determine if a Health Officer Order is warranted.
8. Symptom Monitoring
  1. Symptom monitoring continues for 21 days (or 28 days for those who receive IG PEP) after the most recent date of exposure to a contagious case. The most recent date of exposure is considered day 0. See appendix (Tables 1-3) for monitoring by risk level/setting.
  2. Active Monitoring is daily monitoring via phone call or text throughout the surveillance period. The assigned investigator actively monitors contacts in the following groups:
    • High-risk contacts who do not meet high-risk immunity criteria
    • Low-risk contacts who do not meet low-risk presumption of immunity criteria
    • Any contacts who receive IG PEP until the end of day 21 (they should then passively monitor during days 22-28)
  3. Passive Monitoring is required for all contacts who do not require active monitoring. The investigator advises contacts to monitor for symptoms and to reach out if any develop. The investigator should send a notification on the last day of the surveillance period to inform contacts that the surveillance period will end after that day.
Boxes, Appendix, & Resources
Box 1: Measles Specimen Collection & Lab Testing

Collect all specimens in consultation with VPDC - call at 213-351-7800 from 8:30 am to 5:00 pm Monday to Friday, or 213-974-1234 (option 8) after hours. VPDC will provide guidance on whether specimen testing should be done at PHL or at a commercial lab. If VPDC approves testing at PHL, follow steps below for collecting each sample. VPDC will assist in coordinating a courier if needed.

A. Measles Real-Time Polymerase Chain Reaction (RT-PCR)

PCR of throat or nasopharyngeal (NP) swab and urine is the preferred method for laboratory confirmation of measles.

Sample/Test 1: Throat or Nasopharyngeal (NP) Swab for RT-PCR

  • Laboratory Form (one form per specimen): LAC PHL Measles Throat Swab - PCR or LAC PHL Measles NP Swab - PCR
  • Specimen Type: Throat or NP swab
  • Timing of Specimen Collection: Ideally obtained within 3 days of rash onset, but no later than 2 weeks after rash onset.
  • Minimum Volume Required: At least 3 mL of Viral Transport Media (VTM) or Universal Transport Media (UTM)
  • Collection/Transport Container: Use Dacron tip or flocked swab. After collection, place swab from throat or NP in liquid Viral Transport Media (VTM) or Universal Transport Media (UTM).
  • Storage and Transport: Store specimens refrigerated at 2-8°C. Transport refrigerated on cold packs to the laboratory as soon as possible. Swabs should be submitted on cold packs within 24 hours of collection. If transit time is longer, freeze specimen and transport frozen on dry ice (-20°C or lower).

Sample/Test 2: Urine for RT-PCR

  • Laboratory Form (one form per specimen): LAC PHL Measles Urine - PCR
  • Specimen Type: Urine
  • Timing of Specimen Collection: Collect within 2 weeks of rash onset. Collect 10-50 ml urine in a sterile container midstream, clean-catch. The first morning void is ideal.
  • Minimum Volume Required: 10-50 mL urine
  • Collection/Transport Container: Use screw cap, leakproof, sterile container without preservatives. Urine must be fresh, never frozen.
  • Storage and Transport: Store specimens refrigerated at 2-8°C. Transport refrigerated on cold packs to the laboratory as soon as possible. Do not freeze urine.

B. Measles Antibody Tests (IgM, IgG)

IgM can be used to confirm infection (if not otherwise ruled out by more specific testing). If acute IgM is negative, a convalescent serum specimen can be tested 10-14 days later.

IgG is most often used to assess a person’s immunity to measles. If the person is asymptomatic, IgG can be requested on its own. If the patient is symptomatic, IgG, IgM and PCR (one for throat or NP swab; one for urine) can all be run simultaneously.

Sample/Test 1: Serum for IgM Testing in Symptomatic Patients

  • Laboratory Form (one form per specimen): LAC PHL Serum – IgM Only
  • Specimen Type: Serum
  • Timing of Specimen Collection: At least 72 hours after rash onset.
  • Minimum Volume Required: 7-10 mL of blood/0.25-1 mL of serum
  • Collection/Transport Container: Collect 7-10 mL of blood in SST (red-top, plastic) tube or SST (gold-top, plastic) tube. If possible, separate serum from clot by centrifuging it within one hour of phlebotomy or as soon as possible. If specimen transport is delayed for longer than 5 days, aseptically transfer serum to a screw cap, sterile, leak-proof container.
  • Storage and Transport: Blood specimens should be stored at 2-8°C. Transport refrigerated on cold packs to the laboratory as soon as possible. If testing is delayed longer than 5 days, the specimens should be frozen at -20°C or colder. Specimens should be submitted in a biohazard specimen bag with absorbent material. Transport specimens in an insulated container on cold packs.

Sample/Test 2: Serum for IgG Testing for Immunity in Asymptomatic Persons

  • Laboratory Form (one form per specimen): LAC PHL Serum – IgG Only
  • Specimen Type: Serum
  • Timing of Specimen Collection: As needed to assess immunity
  • Minimum Volume Required: 7-10 mL of blood/1 mL of serum
  • Collection/Transport Container: Collect 7-10 mL of blood in SST (red-top, plastic) tube or SST (gold-top, plastic) tube. If possible, separate serum from clot by centrifuging it within one hour of phlebotomy or as soon as possible. If specimen transport is delayed for longer than 5 days, aseptically transfer serum to a screw cap, sterile, leak-proof container.
  • Storage and Transport: Blood specimens should be stored at 2-8°C. Transport refrigerated on cold packs to the laboratory as soon as possible. If testing is delayed longer than 5 days, the specimens should be frozen at -20°C or colder. Specimens should be submitted in a biohazard specimen bag with absorbent material. Transport specimens in an insulated container on cold packs.

Sample/Test 3: Serum for IgM and IgG Testing in Symptomatic Patients

  • Laboratory Form (one form per specimen): LAC PHL Serum – IgG and IgM
  • Specimen Type: Serum
  • Timing of Specimen Collection: At least 72 hours after rash onset.
  • Minimum Volume Required: 25-1 mL of serum
  • Collection/Transport Container: Collect 7-10 mL of blood in SST (red-top, plastic) tube or SST (gold-top, plastic) tube. If possible, separate serum from clot by centrifuging it within one hour of phlebotomy or as soon as possible. If specimen transport is delayed for longer than 5 days, aseptically transfer serum to a screw cap, sterile, leak-proof container.
  • Storage and Transport: Blood specimens should be stored at 2-8°C. Transport refrigerated on cold packs to the laboratory as soon as possible. If testing is delayed longer than 5 days, the specimens should be frozen at -20°C or colder. Specimens should be submitted in a biohazard specimen bag with absorbent material. Transport specimens in an insulated container on cold packs.
Box 2: Presumption of Immunity Criteria

Contacts may be presumed immune if they meet any of the following criteria:

High Risk

  • Documentation of two doses of measles vaccine given 1968 or later, separated by at least 28 days, with the first dose on or after first birthday
  • A positive IgG test for measles
  • Laboratory confirmation of previous disease

Low Risk

  • Any high-risk presumptive immunity criteria
  • Born prior to 1957
  • Born in any country (including the U.S.) in 1976 or later AND attended a U.S. primary or secondary school*
  • Have written documentation with date of receipt of at least one dose of measles vaccine given on or after first birthday in 1968 or later
  • Served in the U.S. armed forces
  • Entered the U.S. as a permanent U.S. resident or became one in 1996 or later (i.e., have a “green card”)*

*Unless known to be unvaccinated for measles, e.g., having a medical contraindication to vaccination or being philosophically or religiously opposed to vaccinations.

Box 3: Severely Immunocompromised Criteria

Severely immunocompromised patients who are exposed to measles should receive IVIG prophylaxis regardless of immunologic or vaccination status because they might not be protected by the vaccine. Per IDSA, persons with high-level immunosuppression include those:

  • With combined primary immunodeficiency disorder (e.g., severe combined immunodeficiency);
  • Who are receiving cancer chemotherapy;
  • On treatment for ALL within and until at least 6 months after completion of immunosuppressive chemotherapy;
  • Within 2 months after solid organ transplantation;
  • Who have received a bone marrow transplant until at least 12 months after finishing all immunosuppressive treatment, or longer in patients who have developed graft-versus-host disease (GVHD);
  • With HIV infection with a CD4 T-lymphocyte count <200 cells/mm3 (age >5 years) and percentage <15 (all ages) (some experts include HIV-infected persons who lack recent confirmation of immunologic status or measles immunity);
  • 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
  • Receiving certain biologic immune modulators, that is, a tumor necrosis factor-alpha (TNF-α) blocker or rituximab.

After receiving a hematopoietic stem cell transplant (HSCT), duration of high-level immunosuppression is highly variable and depends on type of transplant (longer for allogeneic than for autologous), type of donor and stem cell source, and post-transplant complications such as GVHD and their treatments.

Figure 1: Measles Contact Management Algorithm
Contact Management

7: For measles contacts who have tested measles IgG negative or equivocal in a commercial lab, VPDC should be consulted regarding potential retesting at DPH PHL. If a contact tests positive for IgG at PHL or a commercial lab, consider them to be immune.
8: Contacts at high risk of severe infection (severely immunocompromised people, unvaccinated infants, and susceptible pregnant persons) should receive IG PEP within 6 days or less from the date of last exposure to measles.
9: Implement quarantine from day 7 after first exposure through day 21 after last exposure. If symptoms consistent with measles develop, the exposed person should be isolated and tested.
11: Exclude from high-risk settings (e.g., childcare facilities with infants and healthcare facilities; see definition above) from day 7 (day 5 for healthcare workers in healthcare settings) after first exposure through day 21 after last exposure. Those who have received IG should exclude through day 28 after last exposure.
14: Risk status for pregnant persons who have proof of immunity (at least one MMR dose or positive serology) should be assessed based on other factors such as being a close contact or working in a high-risk setting.
15: If it can be done rapidly, it is recommended that pregnant persons be tested for measles IgG prior to administering IGIV if it is likely that they have received vaccine or had disease. If an exposed pregnant person is IgG negative or IgG equivocal or has unknown status and IgG test results (or retest at PHL) will not be known by day 6 after exposure, administer IGIV.
16: See Box 3 for high-level immunosuppression criteria.
18: A self-reported history of measles disease without documentation is not acceptable as a presumption of immunity. See Box 2 for presumption of immunity criteria. If a low-risk contact has a measles IgG negative or IgG equivocal result, and subsequently provides documentation of two doses of MMR vaccine, base public health decisions on the two documented doses of MMR vaccine, i.e., presume immunity.

Figure 2: Immune Globulin (IG) Dosage for Measles Exposure

   
Indications		    
Dose		    
Interval before MMR vaccine administration

Infants <12 months of age
0.5 mL/kg IM1
(max dose = 15mL)
6 months   

Susceptible immunocompetent contacts <30 kg/66lbs2 		   
0.5 mL/kg IM1
(max dose = 15mL)		    
6 months

Pregnant people without at least 1 MMR dose or positive IgG 		   
400 mg/kg IV (intravenously)   
8 months and nonpregnant
   
Severely immunocompromised persons3 		   
400 mg/kg IV (intravenously)   		    
8 months   

1IMIG should be administered at room temperature and within 6 days of exposure.
2IMIG can be given to any person <30 kg who lacks evidence of measles immunity, but priority should be given to persons exposed in settings with intense, prolonged, close contact (e.g., household, child care, classroom, etc.) or persons who are more likely to develop severe measles (e.g., infants, immunocompromised children). Persons weighing ≥30 kg/66 lbs will not receive an adequate amount of measles antibodies from IMIG. Therefore, there is no recommendation to administer IMIG to these persons. If appropriate, IVIG should be administered.
3See Box 3 for severe immunocompromising conditions.

Table 1: Follow-Up of High-Risk Measles Contacts
High-risk contacts (persons with potential for severe illness if infected or to whom the transmission potential is high) IgG testing*
 PEP† Quarantine if no PEP‡ Exclusion Monitoring§
Unvaccinated infants <6 months of age No IG only Yes Yes** Active
Unvaccinated infants 6-11 months of age†† No MMR or IG†† Yes Yes** Active
Pregnant persons without at least 1 MMR vaccine dose or serologic evidence of immunity‡‡ Yes* IG only‡‡ Yes Yes** Active
Severely immunocompromised§§ No IG only Yes Yes** Active
Household contact or contact with prolonged exposure without 2 documented MMR vaccine doses or serologic evidence of immunity Yes* MMR or IG*** Yes Yes** Active
All other immunocompetent contacts with 2 documented MMR vaccine doses or serologic evidence of immunity No No No No Passive

* For measles contacts who have tested measles IgG negative or equivocal in a commercial lab, VPDC should be consulted regarding potential retesting at DPH PHL. If a contact tests positive for IgG at PHL or a commercial lab, consider them to be immune.
† Contacts at high risk of severe infection (severely immunocompromised people, unvaccinated infants, and susceptible pregnant persons) should receive IG PEP within 6 days or less from the date of first exposure to measles.
‡ Implement quarantine from day 7 after first exposure through day 21 after last exposure. If symptoms consistent with measles develop, the exposed person should be isolated and tested.
§ Persons who receive IG should be actively monitored for 21 days. They should then passively monitor (symptom watch during days 22-28).
** Exclude from high-risk settings (e.g., childcare facilities with infants and healthcare facilities; see definition above) from day 7 (day 5 for healthcare workers in healthcare settings) after first exposure through day 21 after last exposure. Those who have received IG should exclude through day 28 after last exposure.
†† MMR vaccine can be given as PEP within 72 hours or less from the time of exposure to persons ≥6 months of age who do not have contraindications for MMR vaccine. IMIG can be given as PEP for exposed infants <12 months of age ≤6 days from exposure. Persons ≥12 months of age who may have been vaccinated or had disease and receive MMR vaccine as PEP should have blood drawn and tested for measles IgG if measles IgG status is unknown at the time of MMR administration.
‡‡ If it can be done rapidly, it is recommended that pregnant persons be tested for measles IgG prior to administering IVIG if it is likely that they have received vaccine or had disease. If an exposed pregnant person is IgG negative or IgG equivocal or has unknown status and IgG test results (or retest at PHL) will not be known by day 6 after exposure, administer IVIG.
§§ Refer to IDSA guidance for high-level immunosuppression criteria.
*** IMIG can be considered for susceptible persons in this category weighing <30 kg (<66 pounds). There is no recommendation for IMIG in susceptible persons ≥30 kg (≥66 pounds). MMR PEP is preferred if <72 hours have passed since first date of exposure. IVIG is not recommended for low-risk contacts weighing ≥30 kg (≥66 pounds).

Table 2: Follow-Up of Measles Contacts Who Work in A High-Risk Setting
Contacts who work in a healthcare setting or other high-risk setting IgG testing* PEP Quarantine if no PEP‡ Exclusion Monitoring
High-risk for severe disease due to personal medical history and without 2 documented MMR vaccine doses or serologic evidence of immunity See Table 1
Low risk for severe disease and with 1 documented MMR vaccine dose and no serologic evidence of immunity Yes MMR No Yes** Active
Low risk for severe disease and with no documented MMR vaccine doses and no serologic evidence of immunity Yes MMR Yes Yes** Active
With 2 documented MMR vaccine doses or serologic evidence of immunity No No No No Passive

* For measles contacts who have tested measles IgG negative or equivocal in a commercial lab, VPDC should be consulted regarding potential retesting at DPH PHL. If a contact tests positive for IgG at PHL or a commercial lab, consider them to be immune.
‡ Implement quarantine from day 7 after first exposure through day 21 after last exposure. If symptoms consistent with measles develop, the exposed person should be isolated and tested.
** Exclude from high-risk settings (e.g., childcare facilities with infants and healthcare facilities; see definition above) from day 7 (day 5 for healthcare workers in healthcare settings) after first exposure through day 21 after last exposure. Those who have received IG should exclude through day 28 after last exposure.

Table 3: Follow-Up of Low-Risk Measles Contacts in a Low-Risk Setting
Low-risk contacts (immunocompetent persons, persons >12 months of age, not pregnant, not a healthcare worker, not a household contact) IgG testing* PEP Quarantine if no PEP‡ Exclusion Monitoring§
Two documented doses of MMR vaccine (3% will be susceptible) No No No No Passive
Measles IgG positive (<1% will be susceptible)
Meets low-risk presumption of immunity criteria (including 1 documented MMR dose) If desired MMR if desired No Yes** Passive
Unknown or no documentation of vaccination or immune status, without presumption of immunity††† Yes* MMR Yes Yes** Active
Prior measles IgG negative test result*,†††
Known to be unvaccinated††† No MMR Yes Yes** Active

* For measles contacts who have tested measles IgG negative or equivocal in a commercial lab, VPDC should be consulted regarding potential retesting at DPH PHL. If a contact tests positive for IgG at PHL or a commercial lab, consider them to be immune.
‡ Implement quarantine from day 7 after first exposure through day 21 after last exposure. If symptoms consistent with measles develop, the exposed person should be isolated and tested.
§ Persons who receive IG should be actively monitored for 21 days. They should then passively monitor (symptom watch) during days 22-28.
** Exclude from high-risk settings (e.g., childcare facilities with infants and healthcare facilities; see definition above) from day 7 (day 5 for healthcare workers in healthcare settings) after first exposure through day 21 after last exposure. Those who have received IG should exclude through day 28 after last exposure.
††† See Box 2 for “Presumption of Immunity Criteria for Low-Risk Contacts”. A self-reported history of measles disease without documentation is not acceptable as a presumption of immunity. If a low-risk contact has a measles IgG negative or IgG equivocal result, and subsequently provides documentation of two doses of MMR vaccine, base public health decisions on the two documented doses of MMR vaccine, i.e., presume immunity.

Resources

Measles Notification Letters and Flyers:

Measles Case Investigation Forms and Templates:

Measles Laboratory Forms

Measles Guidance and Protocols:

Virtual Trainings:

Acute Communicable Disease Control Manual (B73):



Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.

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