Who are the children at risk? Lessons learned from measles outbreaks

Area of Science:

• Epidemiology
• Public Health
• Pediatrics

Background:

• Measles outbreaks pose a significant public health challenge, particularly in unvaccinated populations.
• Previous measles outbreaks in Jerusalem (2003-2004) predominantly affected the 1-4 years age group.

Purpose of the Study:

• To investigate the epidemiology of a measles outbreak in Jerusalem during 2007-2008.
• To identify shifts in age distribution and risk factors compared to previous outbreaks.
• To inform future public health interventions for measles prevention.

Main Methods:

• Retrospective analysis of 992 measles cases in Jerusalem (2007-2008).
• Comparison of age distribution with historical outbreak data (2003-2004).
• Case-control study (74 cases, 148 controls) to assess risk factors like clinic registration and immunization coverage.

Main Results:

• The 2007-2008 outbreak showed a significant shift, with peak incidence in infants aged 6-12 months (916.2/100,000).
• Infants aged 6-12 months represented a larger proportion of cases (<5 years) compared to the previous outbreak (25.6% vs. 7.7%).
• Measles cases were less likely to be registered in well-baby clinics and had lower DTaP3 (48.6%) and MMR1 (80.8%) vaccine coverage (P<0.001).

Conclusions:

• The study highlights a concerning trend of measles affecting younger infants, necessitating targeted public health strategies.
• Lower immunization coverage and reduced access to well-baby clinics are significant risk factors for measles.
• Intervention programs should prioritize young infants and address barriers to vaccination and healthcare access, considering factors like birth order.