Vaccination Strategies in Special Populations

Measles Vaccination in Vulnerable Populations

Measles vaccines are contraindicated in patients who had a severe allergic reaction to a previous dose of a measles vaccine or to a vaccine component, severe immunosuppression and in pregnancy.

Measles vaccines contain live attenuated virus, and thus pose a risk for severely immunosuppressed individuals due to potential vaccine-virus-induced severe infection. This includes children with primary or acquired immunodeficiency (including human immunodeficiency virus (HIV) infection), malignant neoplasms of the bone marrow or the lymphatic system (including leukemia), and those on systemic immunosuppressants; this latter category is becoming more common with the increasing availability of immunomodulating therapies for autoimmune and rheumatologic diseases. Despite the risks, these children are in the category of patients who most need to be protected. Patients living with HIV whose viral load is suppressed by effective antiretroviral therapy should be vaccinated with two doses of the measles, mumps, and rubella (MMR) vaccine (there are no data on the use of measles, mumps, rubella & varicella (MMRV) in children living with HIV, and its use in this population is contraindicated). Children living with HIV who were vaccinated before antiretroviral therapy (ART) was started should be re-vaccinated. Live vaccines, including measles vaccines, can be given to patients with leukemia, lymphoma and other neoplasms if their disease is in remission, they have restored immunocompetence, and they have completed chemotherapy at least 3 months before. In immunocompromised patients considering international travel, the general rule of avoiding live vaccines (and therefore measles vaccines) applies. Because severely immunocompromised persons may be susceptible to measles and cannot receive the live-attenuated vaccine, international travel (especially to areas with high measles activity) should be discouraged. If travel is unavoidable, prophylactic IG may be considered in these patients.

In 2014, the Infectious Disease Society of America (IDSA) published recommendations for the vaccination of immunocompromised individuals; the recommendations relevant to measles vaccination are shown in Table 5-1.

Individuals who cannot be vaccinated (regardless of reason) should be protected by immunization of immunocompetent household members. If exposed to measles, such persons should receive immunoglobulin (IG) as post-exposure prophylaxis (PEP).

Measles infection during pregnancy heightens the risk of complications for the mother, fetus and newborn. Measles can cause damage to the placenta and harm the fetus, which in turn can result in spontaneous abortion, stillbirth, or the birth of infants with congenital measles. Because measles vaccines are live vaccines and therefore pose a theoretical risk to the fetus, pregnant women and those attempting to become pregnant should not be given a measles vaccine. Women should be advised to avoid pregnancy in the 28 days following measles vaccination.

Measles-containing vaccines can lead to immune thrombocytopenic purpura (ITP) within six weeks post-vaccination; however, the absolute risk is low (2.6 cases per 100,000 vaccine doses). Although the clinical outcome of vaccine-induced ITP is generally less severe than ITP caused by natural infection, careful consideration is necessary for children with chronic ITP, with the risks and benefits carefully weighed based on local measles epidemiology.

Patients receiving blood or other antibody-containing products may exhibit an impaired immune response to a measles vaccine for 3 months or longer. Therefore, the CDC recommends postponing measles vaccination for a period after the blood or blood product (other than washed RBCs) has been administered. The exact amount of time depends on the product administered; the recommendations from the CDC are shown in Table 5-2.

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