Measles outbreak in a fully immunized secondary-school population.

Area of Science:

• Epidemiology
• Immunology
• Public Health

Background:

• Measles outbreaks pose a significant public health concern, particularly in settings with high vaccination coverage.
• Understanding vaccine effectiveness and immune response is crucial for controlling infectious disease transmission.

Purpose of the Study:

• To investigate a measles outbreak in Corpus Christi, Texas, in 1985 among adolescents.
• To assess the relationship between measles vaccination history and antibody levels in a secondary school population.
• To identify factors influencing measles immunity and susceptibility during an outbreak.

Main Methods:

• A serological survey was conducted on 1806 students at two secondary schools.
• Enzyme-linked immunosorbent assay (ELISA) was used to detect measles-specific antibodies.
• Stratified analysis examined the correlation between the number of vaccine doses and antibody response.

Main Results:

• Over 99% of students had vaccination records, yet 4.1% lacked detectable measles antibodies.
• Students receiving two doses of the measles vaccine showed significantly higher seropositivity rates than those receiving one dose.
• Of the unvaccinated students, 14 contracted measles, while none of the seropositive students did.

Conclusions:

• Measles outbreaks can occur in secondary schools despite high vaccination coverage.
• The number of measles vaccine doses is a critical predictor of protective antibody levels.
• Even with high vaccination rates, a portion of the population may remain susceptible, necessitating continued surveillance and potentially booster vaccination strategies.