Importance of coverage and endemicity on the return of infectious trachoma after a single mass antibiotic distribution.
BACKGROUND
As part of the SAFE strategy, mass antibiotic treatments are useful in controlling the ocular strains of chlamydia that cause trachoma. The World Health Organization recommends treating at least 80% of individuals per community. However, the role of antibiotic coverage for trachoma control has been poorly characterized.


RESULTS
In a collection of cluster-randomized clinical trials, mass oral azithromycin was administered to 40 villages in Ethiopia. The village prevalence of ocular chlamydia was determined before treatment, and at two and six months post-treatment. The mean prevalence of ocular chlamydia was 48.9% (95% CI 42.8 to 55.0%) before mass treatments, decreased to 5.4% (95% CI 3.9 to 7.0%) at two months after treatments (p<0.0001), and returned to 7.9% (95% CI 5.4 to 10.4%) by six months after treatment (p = 0.03). Antibiotic coverage ranged from 73.9% to 100%, with a mean of 90.6%. In multivariate regression models, chlamydial prevalence two months after treatment was associated with baseline infection (p<0.0001) and antibiotic coverage (p = 0.007). However, by six months after treatment, chlamydial prevalence was associated only with baseline infection (p<0.0001), but not coverage (p = 0.31).


CONCLUSIONS
In post-hoc analyses of a large clinical trial, the amount of endemic chlamydial infection was a strong predictor of chlamydial infection after mass antibiotic treatments. Antibiotic coverage was an important short-term predictor of chlamydial infection, but no longer predicted infection by six months after mass antibiotic treatments. A wider range of antibiotic coverage than found in this study might allow an assessment of a more subtle association.
Lakew
Takele
T
Orbis International, Addis Ababa, Ethiopia.
Alemayehu
Wondu
W
Melese
Muluken
M
Yi
Elizabeth
E
House
Jenafir I
JI
Hong
Kevin C
KC
Zhou
Zhaoxia
Z
Ray
Kathryn J
KJ
Porco
Travis C
TC
Gaynor
Bruce D
BD
Lietman
Thomas M
TM
Keenan
Jeremy D
JD
Ophthalmic Epidemiol. 2003 Jul;10(3):167-75
12815491
J Clin Microbiol. 2001 Jun;39(6):2375-6
11414248
Lancet. 2005 Apr 9-15;365(9467):1321-8
15823382
Int Ophthalmol Clin. 2007 Summer;47(3):63-76
17667276
Lancet. 2005 Oct 8;366(9493):1296-300
16214600
JAMA. 2008 Feb 20;299(7):778-84
18285589
Sex Transm Infect. 1998 Feb;74(1):66-70
9634309
N Engl J Med. 2005 Jan 27;352(4):414-5; author reply 414-5
15673809
JAMA. 2006 Mar 8;295(10):1142-6
16522834
Ophthalmic Epidemiol. 2010 Mar;17(2):113-7
20302432
Emerg Infect Dis. 2003 May;9(5):596-8
12737745
Invest Ophthalmol Vis Sci. 2007 Apr;48(4):1492-7
17389476
Ophthalmic Epidemiol. 2001 Jul;8(2-3):109-17
11471080
Lancet. 2006 Aug 12;368(9535):589-95
16905023
Nat Med. 1999 May;5(5):572-6
10229236
Lancet. 1993 Aug 21;342(8869):453-6
8102427
Pediatr Infect Dis J. 2004 Mar;23(3):217-20
15014295
Pediatr Infect Dis J. 2008 Jan;27(1):33-7
18162935
PLoS Negl Trop Dis. 2009;3(2):e376
19190781
N Engl J Med. 2004 Nov 4;351(19):1962-71
15525721
BMC Infect Dis. 2007 Aug 07;7:91
17683646
Clin Infect Dis. 1997 Mar;24(3):363-8
9114186
N Engl J Med. 2008 Apr 24;358(17):1870-1
18434662
Bull World Health Organ. 2006 Aug;84(8):613-9
16917648
JAMA. 2004 Aug 11;292(6):721-5
15304470
Clin Infect Dis. 2008 Feb 15;46(4):564-6
18194094
Lancet. 1999 Aug 21;354(9179):630-5
10466664