Seroepidemiology of measles in Addis Ababa, Ethiopia: implications for control through vaccination

Abstract

We undertook a representative survey of measles antibodies in Addis Ababa, Ethiopia 1994, to characterize immunity and transmission. Specific-antibody levels (IU/l) were determined by ELISA for 4654 sera from individuals aged 0-49 years (1805 <15 years) collected by stratified household-cluster sampling. The proportion seronegative (<100 IU/l) was 20 % (95 % CI : 16-25) in children 9-59 months old, declining to 9 % (7-12) in 5-9 year olds, 5 % (4 -7) in 10-14 year olds, and <1% in adults. The proportion of children (<15 years old) with low-level antibody (100-255 IU/l) was 8% (7-10). Vaccination and an absence of a history of measles illness were strongly associated with low-level antibody. History of measles vaccination in 9 months to 14-year-old children was y80%. We estimate a primary vaccine failure rate of 21 % (12-34) and continued high measles incidence of 22 per 100 susceptibles (19-24) per annum. Our data support the introduction of campaign vaccination in the city in 1998, although higher routine vaccine coverage is required to sustain the impact. The implications of a high prevalence of low-level antibody are discussed.

Measles in a Tertiary Institution in Bida, Niger State, Nigeria: Prevalence, Immunization Status and Mortality Pattern

“…15,17 This is in view of the fact that studies have shown that about four in five children develop protective antibody levels when the measles vaccine is administered at nine months of age, and nearly all have a protective antibody response after vaccination at 12 months of age. 18,19 Monthly distribution showed higher frequencies during the dry seasons. This is in keeping with previous observations by earlier studies.…”

A 16-year review of seroprevalence studies on measles and rubella

“…Several authors demonstrated that vaccinated individuals have lower GMT compared with those acquiring immunity through natural infection [9,10,[15][16][17]19,[24][25][26]30,34,69,96,99]. There was insufficient information provided to determine if certain vaccination programmes resulted in a lower GMT.…”

Episodic outbreaks bias estimates of age-specific force of infection: a corrected method using measles as an example

“…In the pre-vaccine era, measles was primarily concentrated in school-aged children in the industrialized world [3]. Developing countries tend to be characterized by an even lower mean age at infection, which is important as disease severity and case-fatality rates are higher in younger children [4–6]. …”