Revaccination against measles--a pilot study

Area of Science:

• Immunology
• Vaccinology
• Public Health

Background:

• Measles vaccination is crucial for preventing disease.
• Understanding long-term antibody persistence after different vaccination schedules is vital for public health strategies.
• Previous studies indicated a decline in antibody titers post-vaccination, necessitating investigations into revaccination efficacy.

Purpose of the Study:

• To evaluate the decline of hemagglutination inhibition (HAI) antibody titres after primary measles vaccination using live attenuated and inactivated-live (K+L) vaccines.
• To assess the effectiveness of revaccination in boosting antibody levels at different time points post-primary immunization.
• To determine factors influencing antibody response to revaccination, including vaccine type, time since primary vaccination, and age at vaccination.

Main Methods:

• Longitudinal study tracking HAI antibody titres in children following primary measles vaccination.
• Comparison of antibody decline rates between live attenuated vaccines and inactivated-live (K+L) vaccines.
• Analysis of antibody responses following revaccination at 5-10 years post-primary immunization, correlating with pre-revaccination titres and time elapsed.

Main Results:

• Live attenuated measles vaccines showed a slow decline in HAI antibody titres over ten years, while K+L vaccines demonstrated a steeper decline.
• Geometric Mean Titres (GMT) remained above protective levels for extended periods with live vaccines but could fall below protective levels sooner with K+L vaccines.
• Revaccination elicited a significantly higher percentage of antibody rise in children previously vaccinated with K+L vaccine (41%) compared to live vaccine alone (5%).

Conclusions:

• The type of primary measles vaccination significantly impacts long-term antibody persistence and the need for revaccination.
• Revaccination within 10-15 years of primary immunization is recommended, especially for individuals with lower pre-revaccination antibody titres.
• Further research is needed to optimize revaccination strategies, including the potential use of less attenuated strains for booster doses.