Clinical Questions about Measles

Protection against measles

Q: How many MMR (or other measles-containing vaccine) doses does my patient need to be considered protected against measles?

Children ages 6-11 months

While MMR vaccination is not routinely recommended for children before 12 months of age, it can be safely administered to children as young as 6 months if they are at increased risk of exposure to measles. Children 6-11 months who are traveling internationally or who live in an area experiencing a measles outbreak where the health department recommends a dose for this age group, can be vaccinated with MMR. Children who receive an MMR vaccine dose before their first birthday should still receive 2 MMR vaccine doses according to the routine schedule at 12–15 months and 4–6 years of age.

Children ages 1 to 6 years

Children in this age group are routinely recommended to receive 1 dose of MMR (or other measles-containing vaccine) at 12–15 months of age and a second dose at 4–6 years of age. Children may receive the second dose early (as soon as 28 days after their first dose) if they are traveling internationally, are a close contact of someone who is immunocompromised, or live in (or are traveling to) an area experiencing a measles outbreak where the health department recommends a second dose for this age group. Children over 12 months of age with HIV infection without evidence of severe immunosuppression are also recommended to receive 2 doses of MMR vaccine separated by at least 28 days.

Children ages 7 years to 18 years

Children in this age group are routinely recommended to have received 2 doses of MMR (or other measles-containing vaccine). If your patient has not received these vaccines, catch-up doses may be administered 28-days or more apart.

Adults

Pregnant women and patients with severe immunocompromise should not receive MMR (or other measles-containing vaccines). Find information on contraindications and precautions: Measles Vaccine Recommendations.

Adults born before 1957 have presumptive immunity to measles from childhood infection1 prior to vaccine introduction in 1963. Unless they are healthcare workers, they do not need a dose of MMR.

Adults born in 1957 or later should receive 1 or 2 doses of MMR (or other measles-containing vaccine) based upon their risk for exposure, etc. Adults with laboratory confirmation of prior measles infection or laboratory evidence of measles immunity (positive measles IgG) do not need MMR for protection against measles. Adults recommended to receive 2 doses of MMR (or other measles-containing vaccine) include:

• Healthcare personnel
• International travelers
• Post-secondary education students
• Close contacts of immunocompromised people
• People with HIV infection without evidence of severe immunosuppression
• People living in or traveling to an area experiencing a measles outbreak where the health department recommends a second dose for adults

If your patient is planning international travel, CDC recommends written documentation (records) showing at least one of the following:

• One dose of measles-containing vaccine for infants aged 6–11 months
• Two doses of measles-containing vaccine for people aged 12 months or older
• Laboratory confirmation of prior measles infection
• Laboratory evidence of measles immunity (positive measles IgG)
• Birth before 1957

Q: What if my patient was vaccinated abroad?

Written documentation of measles-containing vaccine doses received outside the United States may be used as evidence of presumptive measles immunity. Some countries offer measles vaccination before age 12 months. Doses received prior to age 12 months should not be counted in assessing presumptive immunity.

Q: My patient was born before 1957 and was never vaccinated for measles. They are traveling internationally later this year. Should I check their measles titers or vaccinate them with MMR?

CDC considers adults born before 1957 to have presumptive evidence of immunity to measles. Checking for evidence of immunity through blood testing is not recommended, and vaccination with MMR is also not recommended given presumptive evidence of immunity based on birth year. Prior to the introduction of measles vaccines in the 1960s, nearly every child born globally was infected with measles during childhood, and immunity to measles is considered to be lifelong after measles infection. Serologic studies have shown very high rates of immunity among people born before 1957, although seropositivity rates have been lower in these studies for people born during 1957 and later years. While not routinely recommended, older adults may receive MMR vaccine as long as there are no contraindications to measles vaccination.

Q: If my patient was born outside the United States before 1957, are they considered immune to measles?

Yes. All people, regardless of their country of birth, are considered to be presumptively immune to measles if they were born before 1957. Although some countries use a cutoff birth year later than 1957 when determining presumptive immunity, CDC uses a cutoff of birth before 1957 for all people, regardless of country of birth or prior residence.

Q: Is my adult patient who was vaccinated against measles in childhood protected against measles or do they need a booster dose of MMR vaccine?

CDC considers people who received 2 doses of measles vaccine as children according to the CDC vaccination schedule protected for life, and they do not ever need a booster dose. For people who received a first dose after 12 months of age, and who have received 2 MMR doses separated by at least 28 days, there are no recommendations for a 3rd dose of MMR vaccine to improve protection against measles. Generally, adults who are not at high risk for measles exposure who have received 1 documented dose of MMR at 12 months of age or older are considered up to date on MMR vaccination. Certain adults are recommended to have 2 doses of MMR.

Q: Do people who got the killed measles vaccine in the 1960's need to be revaccinated with the current, live measles vaccine?

Yes, people who know they got the killed measles vaccine (an earlier formulation of measles vaccine that is no longer used called "Pfizer-Vax Measles-K"2) should be revaccinated with the current, live measles-mumps-rubella (MMR) vaccine. Not many people fall into this group; the killed vaccine was given to less than 1 million people between 1963 and 1967. If a patient was vaccinated between 1963 and 1967 and does not know the type of vaccine they received, they should be revaccinated with MMR if they have no contraindications to vaccination.

Q: My patient doesn't have access to their childhood vaccination records and doesn't know if they received measles vaccine. Do they need an MMR vaccine?

If they were born before 1957, they are presumed to have immunity to measles from infection in childhood, and they do not require testing for measles immunity (positive measles IgG) or MMR vaccination. If they were born during or after 1957 and are unsure about their vaccination status, they should first try to find their vaccination records or documentation of measles immunity (positive measles IgG result). If they are unable to locate written documentation of measles immunity, such as a record of MMR vaccination or positive measles IgG, they should receive an MMR vaccine. Patients can also get a measles IgG titer drawn to determine if they need an MMR vaccine. There is no harm in getting another dose of MMR vaccine if an individual may already be immune to measles (or mumps or rubella). Please review CDC's adult vaccination algorithm for further details regarding measles vaccination for adults, including additional considerations for healthcare providers, those with upcoming international travel, or other settings of increased risk.

Q: My patient had a negative measles IgG titer despite records documenting receipt of two MMR doses in childhood. Does this patient need an additional MMR dose?

CDC considers most people with documentation of 2 doses of MMR received after 12 months of age, and separated by at least 28 days, to have evidence of measles immunity. CDC does not recommend people who meet these criteria to be vaccinated with MMR even if they have a negative or equivocal result for a measles IgG test. Documented age-appropriate vaccination supersedes the results of subsequent serologic testing. However, if the person tested is a woman of reproductive age and could become pregnant and has a negative or equivocal titer for rubella, they should get a third dose of MMR.

If your patient has a history of immunocompromise (e.g., hematopoietic stem cell transplantation or prior chemotherapy for acute lymphoblastic leukemia), they should consult with their specialist to assess potential need for and timing of revaccination.

Q: Can someone get measles if they have had 2 MMR doses?

The MMR vaccine is very effective at preventing measles (1 dose is 93% effective and 2 doses are 97% effective). A breakthrough infection, defined as a measles infection in a vaccinated person, is rare. It is estimated that about 3 out of 100 people with 2 prior doses of MMR who are exposed to the virus will become infected with measles. Breakthrough infections are more common when there is intense or prolonged exposure to a person with measles. Even when breakthrough infections occur, there are benefits to vaccination. First, people who develop measles despite pre-existing immunity are more likely to have milder illness3 and less likely to develop complications from infection. Second, people with pre-existing immunity are less likely to spread the virus to others4. Therefore, high measles vaccination coverage in communities also protects people who are unable to get vaccinated due to age, pregnancy, or immunocompromised states.

Measles vaccination

Q: Can I give MMR at the same time as other vaccines?

Simultaneous administration of MMR and other vaccines (both inactivated and live vaccines) is recommended by CDC's immunization best practices and has been shown to result in higher vaccine coverage with age-appropriate vaccines.

When administering two different live vaccines (e.g., MMR and varicella vaccines), they can be given on the same day or at least 28 days apart. If two live vaccines are given too close together, but not on the same day, the immune response to the first vaccine might affect the immune response to the second vaccine. If two live vaccines are administered fewer than 28 days apart, the second vaccine administered should not be counted and the dose should be repeated at least four weeks after the invalid dose.

Q: Is it safe for my patient to get the MMR vaccine if they live with someone who is immunocompromised or someone who is pregnant?

Yes. The weakened versions of the measles, mumps, and rubella viruses present in the MMR vaccine are not transmitted from person to person5.

People who are severely immunocompromised or pregnant should not receive MMR vaccine. The vaccine is also not recommended for infants aged less than 6 months. However, no special precautions are required if a person who is getting vaccinated with MMR is in close contact with an infant or a person who is immunocompromised or pregnant. In fact, because people who have compromised immune systems are at high risk for severe complications and cannot be vaccinated, their family members and close contacts who are eligible are recommended to receive 2 doses of MMR vaccine separated by 28 days, unless they have other presumptive evidence of measles immunity.

Q: My patient received an MMR vaccine last week and now has a rash. Do they need to be isolated?

Approximately 5% to 15% of susceptible people who receive MMR vaccine will develop a low-grade fever and/or mild rash 7 to 12 days after vaccination. If this occurs, it does not mean that the person is infectious, and no special precautions (such as isolation or exclusion from work or school) need to be taken. However, if a person vaccinated with MMR develops a rash that you believe could be measles disease (because they've traveled internationally, been exposed to someone with measles, or live in an area with an ongoing measles outbreak), contact your state or local health department, and advise the patient to avoid contact with anyone at increased risk for severe measles.

Q: Can my pregnant patient get an MMR vaccine?

No. MMR vaccine should not be administered to women known to be pregnant or attempting to become pregnant. Because of the theoretical risk to the fetus when the mother receives a live virus vaccine, women should be counseled to avoid becoming pregnant for 28 days after receipt of the MMR vaccine.

Q: Can my breastfeeding patient get an MMR vaccine?

Yes, unless they have a contraindication for MMR vaccination. Neither inactivated nor live-virus vaccines administered to a lactating woman affect the safety of breastfeeding for women or their infants, with the exception of smallpox and yellow fever vaccines. Most live viruses in vaccines have been demonstrated not to be excreted in human milk.

Q: Can my immunocompromised patient get an MMR vaccine?

MMR vaccine should not be administered to individuals with severe immunocompromising conditions6 including:

• Patients with primary or acquired immunodeficiency, including people with immunosuppression associated with cellular immunodeficiencies, hypogammaglobulinemia, dysgammaglobulinemia and AIDS or severe immunosuppression associated with HIV infection.
• Patients with blood dyscrasias, leukemia, lymphomas of any type, or other malignant neoplasms affecting the bone marrow or lymphatic system.
• Patients who have a family history of congenital or hereditary immunodeficiency in first-degree relatives (e.g., parents and siblings), unless the immune competence of the potential vaccine recipient has been substantiated clinically or verified by a laboratory.
• Patients receiving systemic immunosuppressive therapy, including corticosteroids ≥2 mg/kg of body weight or ≥20 mg/day of prednisone or equivalent for patients who weigh >10 kg, when administered for ≥2 weeks.

Q: Who should not get the measles vaccine (MMR)?

Find additional information on contraindications and precautions to MMR vaccination: Measles Vaccine Recommendations.

Q: What are common side effects of MMR vaccination?

Find information on common side effects, available MMR vaccines, and how CDC monitors vaccine safety: Measles, Mumps, Rubella (MMR) Vaccine Safety.

Q: My patient is traveling to an outbreak impacted area of the United States. Should they receive an early MMR dose?

For travel within the United States, additional doses of MMR are recommended only if going to a region that is experiencing an ongoing measles outbreak where state or local public health authorities have recommended additional doses (such as an early dose for infants aged 6–11 months or an accelerated second dose for children aged less than 4 years, or a second dose for adults who had only one dose). CDC is tracking jurisdictions with additional recommendations on the outbreak page: Measles Cases and Outbreaks under "Outbreak Recommendations Issued by Health Departments." Vaccinations for travelers to domestic outbreak regions should be consistent with state or local health department guidance for that region. So, if a dose for infants aged 6–11 months is not recommended for the outbreak-affected area, a dose would not be recommended for an infant traveling to that area).

Infants vaccinated before 12 months of age should be given 2 more doses after their first birthday per the routine schedule, generally at 12-15 months and 4-6 years of age. The risk for widespread measles in the United States, including in airports, remains low due to robust U.S. immunization, surveillance programs, and outbreak response capacity supported by federal, state, tribal, local, and territorial health partners.

Clinical features

Q: Does measles present differently in individuals who have been vaccinated or received post-exposure prophylaxis (PEP)?

Measles infection in people with pre-existing immunity can be challenging to recognize clinically and difficult to characterize serologically. Individuals who have been previously vaccinated against measles or who received post-exposure prophylaxis may have a modified disease presentation, with absent or atypical rash presentation. For instance, the rash may not follow the usual progression. Instead, the initial rash sites may be the trunk and arms rather than the face, and the infection may not result in a full body rash. People with breakthrough infection tend to have milder disease with fewer complications and are less likely to transmit measles.

Q: Does measles present differently in immunocompromised patients?

The clinical presentation of a measles infection in immunocompromised individuals may vary from the typical illness presentation. They may or may not experience rash and the illness course may be prolonged. People with immunocompromising conditions are more likely to develop severe complications of measles such as giant-cell pneumonia and encephalitis.

Isolation for measles

Q: How long should a patient with measles be isolated?

Patients with measles should remain isolated for 4 days after the onset of rash (with onset of rash considered to be day 0). Patients with immunocompromising conditions should remain isolated for the duration of the measles illness due to the potential for prolonged virus shedding. In healthcare settings, patients with measles should remain in Airborne Precautions during the isolation period.

Q: For a patient with atypical or modified measles, how long do they need to be isolated?

There is no change in the infectious period for people with modified measles. Modified measles is used to describe measles presentation in individuals with pre-existing immunity or who have received immunoglobulin (IG) postexposure prophylaxis (PEP). In such cases, typical measles symptoms may be mild or absent, which can complicate diagnosis. The infectious period is 4 days before to 4 days after rash onset (with day of rash onset, if applicable, as day 0). For those who do not have a rash, calculating the infectious period around other symptoms can be possible, recognizing that prodromal symptoms usually occur a few days prior to the rash. Consultation with your local health department may be helpful.

Q: How long are immunocompromised patients with measles considered infectious?

Individuals with severe immune compromise may experience more severe measles and be infectious for longer than the typical 4 days before to 4 days after rash onset. They may also not have a typical measles rash or any rash, which can make determining date of onset challenging to guide infection control practices. They may also have more severe disease and complications from measles infection that may limit assessment of resolution of symptoms. In these cases, measles patients with immunocompromising conditions should remain in Airborne Precautions for the duration of illness. Consult with your facility's infection preventionist or health department for further guidance.

Q: How do I limit potential exposures when moving a patient with suspected measles to isolation?

If the patient is identified prior to entering the facility, they should be given instructions to arrive at the entrance closest to the isolation room. If aged 2 years or older, they should be given a mask to wear before entering the facility. If they are identified after arrival to the facility, they should be masked and isolated from other patients as quickly as possible in an airborne infection isolation room (AIIR) if available, or a private room with a door that shuts. Prompt recognition, masking and isolation minimizes but does not eliminate exposure risks. Consult with your facility's infection preventionist or local health department on managing exposed healthcare personnel, patients and visitors.