Immune response to measles, mumps & rubella vaccine at 9, 12 & 15 months of age

Area of Science:

• Pediatric Infectious Diseases
• Immunology
• Vaccinology

Background:

• Maternal antibody interference can impact infant vaccine responses.
• Understanding optimal timing for MMR vaccination is crucial for effective disease prevention.
• Subclinical viral infections may occur in infants before 15 months of age.

Purpose of the Study:

• To determine the optimal age for administering the measles, mumps, and rubella (MMR) vaccine.
• To assess seroconversion rates and antibody titres following MMR vaccination at different infant ages.
• To evaluate vaccine efficacy and identify potential factors influencing immune response.

Main Methods:

• 164 infants were recruited, with 123 completing the study assessing MMR vaccine response at 9, 12, and 15 months.
• Serum samples were analyzed pre- and post-immunization using haemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) for antibody detection.
• Maternal antibody levels, subclinical infections, and seroconversion rates were evaluated.

Main Results:

• Measles vaccine response was significantly higher (>95%) at 12 or 15 months compared to 9 months (80%).
• Mumps vaccine response was also superior at 12 months (92%) versus 9 months (75%), with lower vaccine failure rates.
• Rubella vaccine demonstrated consistently high seroresponse (>92%) across all tested ages (9, 12, and 15 months).

Conclusions:

• Administering the MMR vaccine at 12 months or later enhances seroconversion rates for measles and mumps.
• The ELISA method was found unreliable for mumps virus antibody testing.
• Optimal MMR vaccination is recommended at 12 months for children not previously vaccinated against measles, or at 12-15 months for those already immunized with measles vaccine.