Case-fatality rate during a measles outbreak in eastern Niger in 2003

Area of Science:

• Epidemiology
• Public Health
• Infectious Diseases

Background:

• The World Health Organization (WHO) estimated measles case-fatality rate (CFR) in West Africa at 4%-6%.
• Niger reported 50,138 measles cases and 201 deaths (CFR, 0.4%) in 2003.
• Routine surveillance data may underestimate the true burden of measles mortality.

Purpose of the Study:

• To determine the true epidemiology and case-fatality rate (CFR) of measles in the Mirriah district, Niger.
• To compare the observed CFR with regional estimates and surveillance data.

Main Methods:

• A comprehensive household investigation was conducted in 22 villages in the Mirriah district.
• Measles cases and deaths were identified, and serum samples were collected for laboratory confirmation.
• A measles case was defined by specific clinical criteria, and deaths within 30 days of rash onset were attributed to measles.

Main Results:

• Measles was serologically confirmed in all sampled villages.
• A total of 945 case patients were identified, with 95.2% younger than 15 years.
• The measles CFR was determined to be 9.7%, significantly higher than surveillance data, with infants under 1 year experiencing the highest CFR (15.6%).

Conclusions:

• The measles CFR in the Mirriah district is likely double the WHO regional estimate and 20-fold higher than routine surveillance suggests.
• Reducing measles mortality in Niger necessitates comprehensive vaccination campaigns targeting all age groups.
• Improvements in routine immunization services and periodic follow-up campaigns are crucial for effective measles control.