Immunity to and infant mortality from measles

Area of Science:

• Immunology
• Pediatrics
• Infectious Diseases

Background:

• High infant mortality from infectious diseases necessitates understanding age-related immune responses.
• Measles infection presents a significant risk to infants, prompting investigation into underlying immune factors.

Purpose of the Study:

• To investigate the age-related immune response to natural measles infection.
• To determine if immunodeficiency contributes to high infant mortality rates from measles.

Main Methods:

• Compared immune responses in infants (<12 months) and older children (>12 months) over 6 weeks post-measles rash onset.
• Assessed lymphocyte transformation, antibody titers (complement-fixing, haemagglutination inhibition), immunoglobulin levels (IgG, IgM, IgA), complement components (C3, C4, Factor B), total hemolytic complement, alternative complement pathway, and leukocyte migration inhibition.

Main Results:

• No significant differences in most immunological parameters between younger and older children.
• Younger infants (group A) had higher absolute lymphocyte counts and haemagglutination inhibition antibody levels, and lower C4 levels compared to older children (group B).
• Five deaths occurred, all in infants under 15 months, but observed immunological differences favored a better prognosis in the younger group.

Conclusions:

• The high mortality rate in infants from measles is unlikely attributable to immunodeficiency.
• Observed immunological differences in younger infants suggest factors other than immunodeficiency are at play.
• Immune responses to measles are largely not age-dependent in the studied parameters.