A tuberculin skin test survey among Ghanaian school children.
BACKGROUND
Ghana has not conducted a national tuberculin survey or tuberculosis prevalence survey since the establishment of the National Tuberculosis Control Programme. The primary objective of this study was therefore to determine the prevalence of tuberculin skin sensitivity in Ghanaian school children aged 6-10 years in 8 out of 10 regions of Ghana between 2004 and 2006.


METHODS
Tuberculin survey was conducted in 179 primary schools from 21 districts in 8 regions. Schools were purposively selected so as to reflect the proportion of affluent private and free tuition public schools as well as the proportion of small and large schools.


RESULTS
Of the 24,778 children registered for the survey, 23,600 (95.2%) were tested of which 21,861 (92.6%) were available for reading. The age distribution showed an increase in numbers of children towards older age: 11% of the children were 6 years and 25%, 10 years. Females were 52.5% and males 47.5%. The proportion of girls was higher in all age groups (range 51.4% to 54.0%, p < 0.001). BCG scar was visible in 89.3% of the children. The percentage of children with a BCG scar differed by district and by age. The percentage of children with a BCG scar decreased with increasing age in all districts, reflecting increasing BCG vaccination coverage in Ghana in the last ten years. The risk of tuberculosis infection was low in the northern savannah zones compared to the southern coastal zones. Using a cut-off of 15 mm, the prevalence of infection ranged from 0.0% to 5.4% and the Annual Risks of Tuberculosis Infection 0.0% to 0.6%. There was an increase in the proportion of infected children after the age of 7 years. Children attending low and middle-class schools had a higher risk of infection than children attending upper-class schools.


CONCLUSIONS
Tuberculosis infection is still a public health problem in Ghana and to monitor the trend, the survey needs to be repeated at 5 years interval.
Addo
Kennedy Kwasi
KK
Bacteriology Department, Noguchi Memorial Institute for Medical Research, Legon, Ghana. kaddo@noguchi.mimcom.org
van den Hof
Susan
S
Mensah
Gloria Ivy
GI
Hesse
Adukwei
A
Bonsu
Christian
C
Koram
Kwadwo Ansah
KA
Afutu
Felix Kwami
FK
Bonsu
Frank Adae
FA
D017677:Age Distribution; D001500:BCG Vaccine; D002648:Child; D005260:Female; D005869:Ghana / Q000453:epidemiology; D006306:Health Surveys; D006801:Humans; D008297:Male; D015995:Prevalence; D012306:Risk; D017678:Sex Distribution; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology*
D001500:BCG Vaccine