Measles Outbreak Case Definition
Summary
The Texas Department of State Health Services (DSHS) and local health departments continue to respond to a large outbreak of measles centered in the South Plains region of West Texas. DSHS has created an outbreak case definition, expanded the number of counties included in the outbreak area, and reiterated recommendations for immunization within that area.
Background
A measles outbreak that began in January in West Texas has grown to include more than 150 cases in nine counties. As of March 3, 94 percent of cases are in six counties: Dawson, Gaines, Lynn, Martin, Terry, and Yoakum, while those counties account for less than one percent of the state’s total population.
This case definition defines the outbreak area as those six counties, extending immunization recommendations to that area. Those include considering an early dose of MMR vaccine for infants ages 6 to 11 months and a second dose for adults who have received only one. It also expands the definition of an epidemiologically linked confirmed case to include patients with a fever and rash who live in or have visited the outbreak area in the last 21 days.
Intent
The definition below defines a geographic area that represents the current measles outbreak area based on a number of factors including case counts, recency of case events, county population, school vaccination coverage, and can be used to:
- Facilitate ease of classifying cases as epidemiologically linked in counties with higher concentrations of known measles spread.
- Lower the threshold for prior approval for testing in these counties.
- Allow for the use of immunization recommendations for MMR in the geographic area designated for this measles outbreak, which include:
- Infants ages 6 to 11 months:
- Administer an early dose of measles, mumps, and rubella (MMR) vaccine.
- Follow the Advisory Committee on Immunization Practices (ACIP) recommended schedule and receive:
- Another dose at 12 through 15 months.
- A final dose at 4 through 6 years.
- Children over 12 months old:
- If the child has not been vaccinated with MMR vaccine, administer one dose immediately and follow with a second dose at least 28 days after the first dose.
- If the child has received one dose of MMR vaccine, administer the second dose as soon as possible, at least 28 days after the first dose.
- Teen and adults with no evidence of immunity:
- Administer one dose of MMR vaccine immediately and follow with a second dose at least 28 days after the first.
- Adults who have received one dose of current (live-attenuated) MMR vaccine should receive a second dose of MMR vaccine:
- For individuals born between 1957 and 1968 who only received an older MMR vaccine, administer one dose of the current MMR vaccine immediately and follow with a second dose at least 28 days after the first dose.
- For individuals born between 1957 and 1968 who have received a dose of the current MMR vaccine, administer the second dose immediately, at least 28 days after the first dose.
- For individuals born after 1968 who only received one dose of the current MMR vaccine, administer a second dose of the current MMR vaccine immediately, at least 28 days after the first dose.
- Adults born before 1957, pregnant women, and people with severe immunodeficiency* are not recommended to receive MMR vaccine.
- Infants ages 6 to 11 months:
Individuals exposed to measles regardless of county of residence should be offered MMR vaccine as postexposure prophylaxis (PEP) within the recommended Centers for Disease Control and Prevention guidance: Prevention of Measles, Rubella, Congenital Rubella Syndrome, and Mumps, 2013.
Increasing MMR coverage is a statewide priority. DSHS encourages all eligible individuals to be up to date on MMR vaccination to prevent measles infection and spread.
The geographic area considered as part of the outbreak will be evaluated on an ongoing basis and can be adjusted when there is enough epidemiologic evidence to support this.
| Condition | Case Definition/Case Classification | Laboratory Confirmation Tests |
|---|---|---|
| Measles (Rubeola) – Texas 2025 Measles Outbreak |
An illness characterized by all of the following: a generalized maculopapular rash lasting at least 3 days; a temperature ≥ 101.0°F (>38.3°C); and cough, coryza, or conjunctivitis Confirmed: An acute, febrile rash illness (temperature can be lower than 101°F or subjective and rash < 3 days) that is:
OR Epidemiologically linked to a laboratory confirmed measles case or by residing in or visiting (within the past 21 days) any of the following counties: Dawson, Gaines, Lynn, Martin, Terry, and Yoakum. |
IgG seroconversion or a significant rise in measles immunoglobulin G antibody level identified by any standard serologic assay*, OR Isolation of measles virus from a clinical specimen*, OR Detection of measles-virus-specific nucleic acid by PCR*, OR A positive serological test for measles immunoglobulin M antibody* (IgM) not otherwise ruled out by other confirmatory testing or more specific measles testing. *Not explained by MMR vaccination during the previous 6-45 days or previous history of disease or presumptive immunity (i.e., born prior to 1957) |
*Examples of people with severe immunodeficiency include hematologic and solid tumors, receipt of chemotherapy, congenital immunodeficiency, or long-term immunosuppressive therapy or patients with human immunodeficiency virus who are severely immunocompromised.