Updated NACI recommendations for measles post-exposure prophylaxis

Area of Science:

• Immunology and infectious disease research.
• Public health policy and vaccine recommendations.

Background:

• Current measles immune globulin (Ig) post-exposure prophylaxis (PEP) recommendations may be suboptimal due to declining antibody concentrations and evolving population immunity.
• High measles vaccination rates have reduced measles virus circulation, altering the landscape for blood donor immunity.

Purpose of the Study:

• To review and update recommendations for measles Ig PEP in susceptible infants, immunocompromised, and pregnant individuals.
• To define optimal dosing and routes of administration for measles Ig PEP to prevent severe disease.

Main Methods:

• A review of key literature, international practices, and product information for human Ig products used in measles PEP.
• Evidence-based changes to PEP recommendations were proposed and approved by the National Advisory Committee on Immunization (NACI).

Main Results:

• Measles-mumps-rubella (MMR) vaccine remains the preferred PEP for immunocompetent individuals over six months old within 72 hours of exposure.
• Specific intramuscular immunoglobulin (IMIg) and intravenous immunoglobulin (IVIg) dosing and administration guidelines are provided for infants under 12 months, and for pregnant or immunocompromised individuals.
• Ig PEP is not recommended for immunocompetent individuals over 12 months due to low complication risk and administration challenges.

Conclusions:

• NACI has updated measles PEP recommendations to align with current evidence and best practices for severe disease prevention in Canada.
• The updated guidelines include considerations for the off-label use of IVIg in specific clinical scenarios, reflecting international practices.