Breakthrough Infections: A Challenge towards Measles Elimination?

Area of Science:

• Immunology
• Epidemiology
• Virology

Background:

• Measles is highly contagious, with vaccines available.
• Vaccinated individuals can still contract measles (breakthrough cases).
• Breakthrough cases increase with higher vaccination coverage.

Purpose of the Study:

• To review measles breakthrough cases.
• To understand their clinical, serological, epidemiological, and molecular characteristics.
• To assess their contribution to measles transmission.

Main Methods:

• Literature review of measles breakthrough cases.
• Analysis of clinical, serological, epidemiological, and molecular data.
• Assessment of vaccination failure types (primary and secondary).

Main Results:

• Breakthrough cases are more common in highly vaccinated populations.
• Primary vaccination failure occurs in ~5% of vaccinees.
• Secondary vaccination failure (waning immunity) occurs in 2-10% of vaccinees, typically 6-26 years post-vaccination.
• Breakthrough cases often present with modified measles (lower viral load, milder symptoms).

Conclusions:

• Vaccination failures, including waning immunity, contribute to measles transmission.
• Assessing antibody protection decline is vital for measles elimination.
• Targeted catch-up vaccination strategies are essential.