Tuberculosis epidemiology in six provinces of Vietnam after the introduction of the DOTS strategy.
METHODS
Six provinces in Vietnam where the DOTS strategy was introduced in 1989.


OBJECTIVE
To assess the impact of improved tuberculosis (TB) control on TB epidemiology in Vietnam.


METHODS
Data from the surveillance system in the period 1990-2003 were analysed to assess trends of notification rates and the mean ages of notified cases. Data from repeated tuberculin surveys in the period 1986-2002 were estimated to assess the prevalence of TB infection, the annual risk of infection and its trend using various cut-off points in those with and without bacille Calmette-Guérin (BCG) scar.


RESULTS
Age-standardised notification rates in the period 1996-2003 declined significantly, by 2.6% to 5.9% per year, in five provinces. However, in four provinces notification rates in the age group 15-24 years increased significantly, by 4.5% to 13.6% per year, during this period. The mean age of newly diagnosed patients with smear-positive TB increased up to 1995 but decreased thereafter. The annual risk of TB infection showed a significant annual decrease (4.9% per year) in one province in surveys performed between 1986 and 1997, and in two provinces (6.6% and 4.7%) in surveys conducted between 1993 and 2002.


CONCLUSIONS
These data suggest limited impact to date of the DOTS strategy in Vietnam.
Huong
N T
NT
National Hospital of Tuberculosis and Respiratory Diseases, Hanoi, Vietnam.
Duong
B D
BD
Co
N V
NV
Quy
H T
HT
Tung
L B
LB
Broekmans
J F
JF
Bosman
M C
MC
Verhage
C
C
Kalisvaart
N
N
Borgdorff
M W
MW
Cobelens
F G
FG
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D023801:Directly Observed Therapy; D006801:Humans; D008875:Middle Aged; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy* / Q000453:epidemiology*; D014744:Vietnam / Q000453:epidemiology