title: Estimating mother-to-child HIV transmission rates in Cameroon in 2011: a computer simulation approach.
abstract: BACKGROUND
  Despite the progress in the Prevention of the Mother-to-Child Transmission of HIV (PMTCT), the paediatric HIV epidemic remains worrying in Cameroon. HIV prevalence rate for the population of pregnant women was 7.6% in 2010 in Cameroon. The extent of the paediatric HIV epidemic is needed to inform policymakers. We developed a stochastic simulation model to estimate the number of new paediatric HIV infections through MTCT based on the observed uptake of services during the different steps of the PMTCT cascade in Cameroon in 2011. Different levels of PMTCT uptake was also assessed.
  
  
  METHODS
  A discrete events computer simulation-based approach with stochastic structure was proposed to generate a cohort of pregnant women followed-up until 6 weeks post-partum, and optionally until complete breastfeeding cessation in both prevalent and incident lactating HIV-infected women. The different parameters of the simulation model were fixed using data sources available from the 2011 national registry surveys, and from external cohorts in Cameroon. Different PMTCT coverages were simulated to assess their impact on MTCT. Available data show a low coverage of PMTCT services in Cameroon in 2011.
  
  
  RESULTS
  Based on a simulation approach on a population of 995, 533 pregnant women, the overall residual MTCT rate in 2011 was estimated to be 22.1% (95 % CI: 18.6%-25.2%), the 6-week perinatal MTCT rate among prevalent HIV-infected mothers at delivery is estimated at 12.1% (95% CI: 8.1%-15.1%), with an additional postnatal MTCT rate estimated at 13.3% (95% CI: 9.3%-17.8%). The MTCT rate among children whose mothers seroconverted during breastfeeding was estimated at 20.8% (95% CI: 14.1%-26.9%). Overall, we estimated the number of new HIV infections in children in Cameroon to be 10, 403 (95% CI: 9, 054-13, 345) in 2011. When PMTCT uptake have been fixed at 100%, 90% and 80%, global MTCT rate failed to 0.9% (9% CI: 0.5%-1.7%), 2.0% (95% CI: 0.9%-3.2%) and 4.3% (95% CI: 2.4%-6.7%) respectively.
  
  
  CONCLUSIONS
  This model is helpful to provide MTCT estimates to guide the national HIV policy in Cameroon. Increasing supply and uptake of PMTCT services among prevalent HIV infected pregnant women, as well as HIV-prevention interventions including the offer and acceptance of HIV testing and counselling in lactating women could reduce significantly the residual HIV MTCT in Cameroon. A public health effort should be made to encourage health care workers and pregnant women to use PMTCT services until complete breastfeeding cessation.
authors.affiliation: National Advanced School of Engineering, The University of Yaoundé I, PO Box 8390, Yaoundé, Cameroon. hermine.nguena@gmail.com.
authors.forename: Hermine L Nguena
authors.initials: HL
authors.lastname: Nguefack
authors.affiliation: National Advanced School of Engineering, The University of Yaoundé I, PO Box 8390, Yaoundé, Cameroon. gwet@visualstat.com.
authors.forename: Henri
authors.initials: H
authors.lastname: Gwet
authors.affiliation: Inserm, U897, Bordeaux, France. Sophie.Desmonde@isped.u-bordeaux2.fr.|Bordeaux School of Public Health, The University of Bordeaux, Bordeaux, France. Sophie.Desmonde@isped.u-bordeaux2.fr.
authors.forename: Sophie
authors.initials: S
authors.lastname: Desmonde
authors.affiliation: Centre International de Référence Chantal Biya (CIRCB) pour la recherche sur la prévention et la prise en charge du VIH/SIDA, Yaoundé, Cameroun. ooukem@gmail.com.|Centre de Recherche Médicale et Sanitaire (CERMES), member of Réseau International des Instituts Pasteur, Niamey, Niger. ooukem@gmail.com.
authors.forename: Odile Ouwe Missi
authors.initials: OO
authors.lastname: Oukem-Boyer
authors.affiliation: Centre International de Référence Chantal Biya (CIRCB) pour la recherche sur la prévention et la prise en charge du VIH/SIDA, Yaoundé, Cameroun. nkenfou@yahoo.com.
authors.forename: Céline
authors.initials: C
authors.lastname: Nkenfou
authors.affiliation: Centre Pasteur du Cameroun, member of Réseau International des Instituts Pasteur, Yaoundé, Cameroun. tejiokem@pasteur-yaounde.org.
authors.forename: Mathurin
authors.initials: M
authors.lastname: Téjiokem
authors.affiliation: Centre Pasteur du Cameroun, member of Réseau International des Instituts Pasteur, Yaoundé, Cameroun. ttpatty@yahoo.com.
authors.forename: Patrice
authors.initials: P
authors.lastname: Tchendjou
authors.affiliation: Centre International de Référence Chantal Biya (CIRCB) pour la recherche sur la prévention et la prise en charge du VIH/SIDA, Yaoundé, Cameroun. domkam74@gmail.com.
authors.forename: Irénée
authors.initials: I
authors.lastname: Domkam
authors.affiliation: Inserm, U897, Bordeaux, France. valeriane.leroy@isped.u-bordeaux2.fr.|Bordeaux School of Public Health, The University of Bordeaux, Bordeaux, France. valeriane.leroy@isped.u-bordeaux2.fr.|Inserm U1027 Epidémiologie et analyses en santé publique : risques, maladies chroniques et handicaps, Université Paul Sabatier Toulouse 3, Toulouse, France. valeriane.leroy@isped.u-bordeaux2.fr.
authors.forename: Valériane
authors.initials: V
authors.lastname: Leroy
authors.affiliation: Inserm, U897, Bordeaux, France. ahmadou.alioum@u-bordeaux.fr.|Bordeaux School of Public Health, The University of Bordeaux, Bordeaux, France. ahmadou.alioum@u-bordeaux.fr.
authors.forename: Ahmadou
authors.initials: A
authors.lastname: Alioum
mesh_terms: D000293:Adolescent; D000328:Adult; D001942:Breast Feeding; D002163:Cameroon / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D058872:Epidemics; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000503:physiopathology / Q000635:transmission*; D006801:Humans; D007223:Infant; D018445:Infectious Disease Transmission, Vertical / Q000706:statistics & numerical data; D007774:Lactation; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D015995:Prevalence; D055815:Young Adult