What is the guidance on Measles, Mumps, and Rubella (MMR) vaccine administration during a measles outbreak?

From the Guidelines

All eligible individuals should ensure they are fully vaccinated with the MMR (measles, mumps, rubella) vaccine to protect against measles, especially during an outbreak. The standard MMR vaccination schedule consists of two doses: the first dose at 12-15 months of age and the second dose at 4-6 years. For adults born after 1957 who have not been vaccinated or lack documentation of immunity, at least one dose of MMR is recommended, with certain high-risk groups needing two doses given at least 28 days apart 1.

Key Considerations

• During an outbreak, infants 6-11 months old may receive an early dose for temporary protection, but they will still need the regular two-dose series starting at 12 months.
• The vaccine is highly effective, with approximately 97% protection after two doses.
• It works by introducing weakened forms of the viruses, stimulating the immune system to develop protective antibodies without causing disease.
• The MMR vaccine is contraindicated for pregnant women, severely immunocompromised individuals, and those with severe allergic reactions to vaccine components.
• Common side effects are mild and include soreness at the injection site, fever, and mild rash.

Special Situations

• For susceptible persons aged greater than or equal to 6 months who are household contacts of measles patients, use of vaccine within 72 hours of initial exposure is also acceptable 1.
• However, measles often is not recognized as such until greater than 72 hours after onset, and administration of IG to susceptible household contacts who are not vaccinated within 72 hours of initial exposure is recommended.
• Adults born before 1957 generally are considered immune to measles, but those born during or after 1957 should receive 1 or more doses of MMR unless they have a medical contraindication, documentation of 1 or more doses, history of measles based on health care provider diagnosis, or laboratory evidence of immunity 1.

Outbreak Control

• During measles outbreaks, evidence of adequate vaccination for school-aged children, adolescents, and adults born during or after 1957 who are at risk for measles exposure and infection consists of two doses of measles-containing vaccine separated by at least 28 days, with the first dose administered no earlier than the first birthday 1.
• A second dose of MMR is recommended for adults who have been recently exposed to measles or are in an outbreak setting, have been vaccinated previously with killed measles vaccine, have been vaccinated with an unknown type of measles vaccine during 1963–1967, are students in postsecondary educational institutions, work in a health care facility, or plan to travel internationally 1.

From the Research

Guidance on MMR Vaccine Administration

• The administration of the Measles, Mumps, and Rubella (MMR) vaccine during a measles outbreak is guided by several studies 2, 3, 4, 5, 6.
• According to a study published in BMJ open, children under the age of 12 months may receive an early dose of MMR vaccine to provide short-term protection in the case of a disease outbreak 2.
• Another study published in Clinical infectious diseases found that the effectiveness of MMR post-exposure prophylaxis (PEP) was 83.4% in preventing measles among nonimmune contacts aged <19 years 3.
• The German Standing Committee on Vaccination (STIKO) recommends passive immunization with immunoglobulins as post-exposure prophylaxis after contact with measles, particularly for unprotected individuals at high risk of complications 4.
• The National Advisory Committee on Immunization (NACI) recommends that susceptible immunocompetent individuals six months of age and older, who are exposed to measles and who have no contraindications, be given MMR vaccine within 72 hours of the exposure 5.
• A simulation study published in PloS one found that voluntary isolation and home quarantine coupled with one or two other interventions had the greatest reduction in the number of secondary cases infected by the index case and the probability of escape situations 6.

Post-Exposure Prophylaxis

• Post-exposure prophylaxis (PEP) with MMR vaccine or immune globulin (IG) is recommended for individuals exposed to measles 3, 4, 5.
• The effectiveness of IG PEP was found to be 100% in preventing measles among nonimmune contacts aged <19 years 3.
• NACI recommends that susceptible infants younger than six months of age receive intramuscular immunoglobulin (IMIg) at a concentration of 0.5 mL/kg, to a maximum dose of 15 mL administered over multiple injection sites 5.
• For susceptible contacts who are pregnant or immunocompromised, NACI recommends IMIg at a concentration of 0.5 mL/kg or intravenous immunoglobulin (IVIg) at a dose of 400 mg/kg 5.

Public Health Interventions

• Public health interventions, such as contact investigations and post-exposure prophylaxis, are crucial in controlling and preventing measles transmission 6.
• A simulation study found that voluntary isolation and home quarantine coupled with one or two other interventions had the greatest reduction in the number of secondary cases infected by the index case and the probability of escape situations 6.
• The study highlights the importance of a rapid public health outbreak response to limit measles transmission following case identification 3, 6.