Measles Outbreak Response

Why is the data in the Center for Outbreak Response Innovation’s (CORI) measles dashboard different from other dashboards? 

CORI uses multiple data sources to develop our measles tracker. We draw on federal data, health department information, media reports, and other data sets to provide a timely snapshot of what is happening across the U.S. and through recent cases at a jurisdictional level. CORI also reports on measles cases in Canada and Mexico, using government sources. We want to provide relevant, timely, and easy to use data to help people make informed decisions. In collecting and analyzing disease and outbreak data, it is not uncommon for groups to use different data sets, look at trends over different periods of time, and/or focus on specific population groups, which can give different views.

How does CORI maintain its measles dashboard?

CORI seeks to develop innovative and timely tools, like the measles dashboard, to track and respond to disease outbreaks. While the completeness of collected information can vary by jurisdiction, CORI prioritizes state and local health department data, which we validate on a daily (Monday to Friday) basis to ensure the measles dashboard is as current and accurate as possible. We then cross-check against CDC’s national totals. This approach means we sometimes capture cases earlier or later than CDC’s aggregated reporting schedule depending on reporting rates. We aim to align our updates within hours of CDC data release and no later than by the end of the day. Only in the event of a discrepancy or a data gap, which has not been formally reported by a state or local health department or other public health entity, do we use local news reports and other informal sources.

Measles, a highly contagious viral disease, has been experiencing a concerning resurgence globally and in the United States in recent years. Despite the availability of a safe and effective vaccine, outbreaks continue to occur, primarily due to gaps in vaccination coverage and the virus's high transmissibility. In 2019, the World Health Organization (WHO) reported a significant increase in measles cases worldwide, with 869,770 cases reported in that year alone, the highest number since 1996. This trend has worsened following the COVID-19 pandemic due to disruptions in vaccination efforts and surveillance activities combined with increased vaccine hesitancy, misinformation about vaccine safety, inadequate access to healthcare services, conflict, and humanitarian crises. 

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Measles Risk Assessment 4.25.25

Risk Assessment Methodology 9.19.24 

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Risk Assessment 9.19.24 

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Risk Assessment 1.31.25

Measles Risk Assessment 2.21.25

Measles Risk Assessment 2.26.25

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Measles Risk Assessment 3.4.25

Measles Risk Assessment 3.10.25

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Measles Risk Assessment 3.19.25

Measles Risk Assessment 3.21.25

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Measles Risk Assessment 4.9.25

Measles Risk Assessment 4.19.25_

Is getting sick with measles naturally better than the measles vaccination? Should I expose myself or my child to measles?

No, getting sick with measles is not better than getting the measles vaccine. While a measles infection does provide natural immunity, it comes with serious risks, including hospitalization, pneumonia, encephalitis (brain inflammation), complications during pregnancy, and even death. Long-term complications include immune amnesia, which can weaken immunity and increase vulnerability to other infections, and subacute sclerosing panencephalitis (SSPE), a rare but fatal brain disease that can develop years after infection.

The measles vaccine provides strong, safe immunity without these risks. Attending a “measles party” to intentionally expose yourself or a child to measles is dangerous and not recommended. It puts individuals at unnecessary risk of severe illness and complications. The best protection for yourself and your community is vaccination.

Can Vitamin A or cod liver oil prevent or cure measles?

No, vitamin A and cod liver oil (which is rich in vitamin A) do not prevent or cure measles. The measles vaccine is the only way to prevent measles. There is no specific treatment for measles, only supportive care.

However, vitamin A supplementation may reduce measles severity and risk of complications, including death. The CDC and American Academy of Pediatrics recommend vitamin A for children with measles, especially if hospitalized. There is no CDC recommendation for the use of cod liver oil as part of measles supportive care.

Since excessive vitamin A intake can be harmful, supplementation should only be given when medically necessary and under the supervision of a healthcare provider. Most children in the US receive sufficient vitamin A through their diet.

Can measles vaccine cause autism?

No. Studies have repeatedly shown no link between the measles vaccine and autism.

Does a positive IgG test mean someone has a measles infection?

No, a positive IgG test indicates immunity to measles from past infection or vaccination, not an active infection. 

Can measles vaccine cause measles illness?

No, the measles vaccine cannot cause measles illness. The MMR vaccine contains a weakened, non-infectious strain (MeVA, genotype A), which does not cause or spread measles but helps the body develop immunity. No human-to-human transmission of the measles vaccine virus has ever been reported.

The current Texas outbreak is linked to a naturally circulating, disease-causing strain (wild-type, genotype D8), which has been circulating since 1990 in regions including Europe, North Africa, the Middle East, and Southwest Asia.

Are measles boosters recommended?

There are currently no recommendations to receive a third dose of MMR vaccine during measles outbreaks. 

During measles outbreaks, state and local health departments may adjust or implement temporary accelerated vaccination schedules, in addition to routine recommendations, for populations at-risk who are residing in or visiting the affected areas. This may include recommending:

• Infants (6–11 months old): Early dose, followed by routine two-dose series at 12–15 months and 4–6 years, per CDC guidelines.
• Children (1–4 years old): Early second dose, at least 28 days after the first.
• Adults: Second dose if only one dose was received, given at least 28 days after the first.
• Healthcare personnel in a healthcare facility or facilities serving outbreak areas are recommended to receive two MMR doses regardless of birth year if they lack laboratory-confirmed immunity.

The following populations, aged 12 months of age or older, are recommended to receive at least two doses of MMR vaccine, at least 28 days apart, if they lack measles immunity:

• Students at post-high school educational institutions
• International travelers
  • Infants (6 through 11 months) traveling internationally should receive an early dose of MMR if they lack immunity against measles.  These infants will still need the routine two-dose series.
• Household and close contacts of immunocompromised persons
• People with Human Immunodeficiency Virus (HIV) infection (without severe immunosuppression)

Certain populations may benefit from an additional MMR dose or revaccination:

• Adults vaccinated before 1968 with an inactivated vaccine or unknown vaccine type
  • The CDC recommends getting at least one dose of the current, more effective live attenuated MMR vaccine for better protection.
• Individuals without evidence of measles immunity or unsure of their vaccination status
• If vaccination status is not known, getting the MMR vaccine is safe and effective. Check with a healthcare provider for guidance.

CLICK HERE TO DOWNLOAD AND VIEW REFERENCES

• Measles Case Definitions [CDC]
• US Cases and Outbreaks [CDC]
• Measles Vaccine Recommendations [CDC]
• Measles Vaccination for Specific Groups [CDC]

Overview: The following outbreak response templates were developed by CORI in collaboration with health department partners and aim to standardize measles outbreak responses and reduce the staff time required to mount an initial response. These templates are provided as a general guide and should be tailored to meet the specific requirements and regulations of your local or state health department or relevant authorities. It is crucial that the content and instructions align with current guidelines and legal standards established by your jurisdiction.

Case Investigation Templates 

Communication Templates

Operational Workflows 

Templates for Public Health Preparedness Offices 

The following resources have been provided by the Jefferson County Health Department (MO), and have been tested through exercises and real-world responses.  

Overview: The following guidance and educational materials have been developed by CORI, CDC, state and local health departments to support providers and clinic administrators prepare for, recognize, and respond to measles. 

Case Investigation Tools and Protocols

Toolkits for Local Health Departments

Toolkit for School Nurses

Overview: The following guidance and educational materials have been developed by CORI, CDC, state and local health departments to support providers and clinic administrators prepare for, recognize, and respond to measles. 

Guidance Documents 

Office Materials for Patients

Outbreak Lessons Learned

• Containing a Measles Outbreak in Minnesota 2017 Methods and Challenges
• Public Health Response During Measles Outbreaks in Elimination Settings
• Measles Outbreak Associated with a Migrant Shelter — Chicago, Illinois, February–May 2024