Epidemiology of Measles in the Philippines
Background. Measles cases have decreased ever since vaccination has been introduced through the DOH Expanded Program on Immunization (DOH EPI) in the Philippines. Elimination is the current goal. However, despite high vaccine coverage, a nationwide outbreak occurred in 2013.
Objectives. This study aimed to present measles incidence rates before and after the introduction of the measles vaccine, describe the changing epidemiology of measles, and assess the effectiveness of measles vaccination and baseline measles reporting.
Methods. National data from 1960 to 2014 were used to determine incidence of measles and describe its epidemiology. Vaccine coverage and data on measles surveillance were used to estimate vaccine effectiveness by birth cohort and age group.
Results. Reported measles incidence decreased after the introduction of measles vaccine compared to prevaccination levels (pre-vaccination: 36 per 100,000 to 73 per 100,000; 2008-2014 confirmed measles incidence: 1.47 to 23.76 per 100,000, suspected measles-5.7 to 58.08 per 100,000). A shift in the age distribution of cases was noted during the outbreak. Vaccine effectiveness by birth cohort ranged from 85-96% while the lowest VE estimate by age group was seen among those aged 26-30 years.
Conclusion. Measles vaccine coverage should target wider age groups. Measles surveillance should be improved to help in evidence-based decisions for a more effective plan towards measles elimination.