title: Tracing defaulters in HIV prevention of mother-to-child transmission programmes through community health workers: results from a rural setting in Zimbabwe.
abstract: BACKGROUND
  High retention in care is paramount to reduce vertical human immunodeficiency virus (HIV) infections in prevention of mother-to-child transmission (PMTCT) programmes but remains low in many sub-Saharan African countries. We aimed to assess the effects of community health worker-based defaulter tracing (CHW-DT) on retention in care and mother-to-child HIV transmission, an innovative approach that has not been evaluated to date.
  
  
  METHODS
  We analyzed patient records of 1878 HIV-positive pregnant women and their newborns in a rural PMTCT programme in the Tsholotsho district of Zimbabwe between 2010 and 2013 in a retrospective cohort study. Using binomial regression, we compared vertical HIV transmission rates at six weeks post-partum, and retention rates during the perinatal PMTCT period (at delivery, nevirapine [NVP] initiation at three days post-partum, cotrimoxazole (CTX) initiation at six weeks post-partum, and HIV testing at six weeks post-partum) before and after the introduction of CHW-DT in the project.
  
  
  RESULTS
  Median maternal age was 27 years (inter-quartile range [IQR] 23 to 32) and median CD4 count was 394 cells/µL(3) (IQR 257 to 563). The covariate-adjusted rate ratio (aRR) for perinatal HIV transmission was 0.72 (95% confidence intervals [95% CI] 0.27 to 1.96, p=0.504), comparing patient outcomes after and before the intervention. Among fully retained patients, 11 (1.9%) newborns tested HIV positive. ARRs for retention in care were 1.01 (95% CI 0.96 to 1.06, p=0.730) at delivery; 1.35 (95% CI 1.28 to 1.42, p<0.001) at NVP initiation; 1.78 (95% CI 1.58 to 2.01, p<0.001) at CTX initiation; and 2.54 (95% CI 2.20 to 2.93, p<0.001) at infant HIV testing. Cumulative retention after and before the intervention was 496 (85.7%) and 1083 (87.3%) until delivery; 480 (82.9%) and 1005 (81.0%) until NVP initiation; 303 (52.3%) and 517 (41.7%) until CTX initiation; 272 (47.0%) and 427 (34.4%) until infant HIV testing; and 172 (29.7%) and 405 (32.6%) until HIV test result collection.
  
  
  CONCLUSIONS
  The CHW-DT intervention did not reduce perinatal HIV transmission significantly. Retention improved moderately during the post-natal period, but cumulative retention decreased rapidly even after the intervention. We showed that transmission in resource-limited settings can be as low as in resource-rich countries if patients are fully retained in care. This requires structural changes to the regular PMTCT services, in which community health workers can, at best, play a complementary role.
authors.affiliation: Operational Centre Barcelona, Médecins Sans Frontières/Doctors Without Borders, Barcelona, Spain; florianvogt@hotmail.com.
authors.forename: Florian
authors.initials: F
authors.lastname: Vogt
authors.affiliation: Operational Centre Barcelona, Médecins Sans Frontières/Doctors Without Borders, Barcelona, Spain.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Ferreyra
authors.affiliation: Operational Centre Barcelona, Médecins Sans Frontières/Doctors Without Borders, Barcelona, Spain.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bernasconi
authors.affiliation: Tsholotsho Project, Médecins Sans Frontières/Doctors Without Borders, Tsholotsho, Zimbabwe.
authors.forename: Lewis
authors.initials: L
authors.lastname: Ncube
authors.affiliation: Zimbabwe Mission, Médecins Sans Frontières/Doctors Without Borders, Harare, Zimbabwe.
authors.forename: Fabian
authors.initials: F
authors.lastname: Taziwa
authors.affiliation: Tsholotsho District Medical Office, Ministry of Health and Child Welfare, Tsholotsho, Zimbabwe.
authors.forename: Winnie
authors.initials: W
authors.lastname: Marange
authors.affiliation: Tsholotsho Project, Médecins Sans Frontières/Doctors Without Borders, Tsholotsho, Zimbabwe.
authors.forename: David
authors.initials: D
authors.lastname: Wachi
authors.affiliation: Department of Medical Biometry and Epidemiology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Becher
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003150:Community Health Workers; D005260:Female; D015658:HIV Infections / Q000517:prevention & control*; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D019829:Nevirapine / Q000627:therapeutic use; D011247:Pregnancy; D012189:Retrospective Studies; D015030:Zimbabwe
chemical_list: D019829:Nevirapine
keywords: HIV; Médecins Sans Frontières/Doctors Without Borders; Zimbabwe; community health workers; defaulter tracing; prevention of mother-to-child transmission; retention in care; vertical transmission