Statistical Models of Postnatal Transmission of HIV Type-I Infection from Mother to Child on Global Perspectives

About 5.0 millions of Indians suffer from HIV; the retention rate was <10–15%. Though experimental results have shown the transitions between postnatal transmission and survivability of PLHIVs, little is known about the dynamism of progression of HIV and transmission probability. Therefore, the present chapter demonstrated various statistical models for estimation of HIV postnatal transmission at population level (Agarwal D, Chakravarty J, Sundar S, Gupta V, Bhatia BD: Indian Pediatr 45:140–143, 2008). The incidence rate of postnatal transmission and HIV survival rate of ANCs data was extracted from database of “ART” Karnataka CMIS (obtained from the State AIDS control organization). The models were built for the likelihood estimation and size of the population under the age of 15 years; the data was obtained from ART on monthly intervals, starting from 2005 to 2018. The non-AIDS mortality rate and annual number of births to mothers, who are on HIV-positive and HIV-negative data sets, were originally extracted from the ASSA AIDS database source, and also the demographic data sets were obtained from the patient pre-ART registration card, and ASSA model is a widely used model for estimation of geometric progression of HIV epidemic at population level (Department of AIDS Control, Ministry of Family Welfare, Government of India: Annual report 2008–2009. http://nacoonline.org/upload/Publication/Annual_Report_NACO_2008-09.pdf. Accessed on 27 Feb 2010, 2008). This model will allow for the estimation of incidence of HIV in different modes. Children under the age of 15 years, the transmission from infected mothers on or before birth (intrapartum or intrauterine transmission) and transmission from infected mothers after birth, as a result of breastfeeding (Asnake S, Amsalu S: Ethiop J Health Dev 19:24–28, 2005; Allen S, Stephenson R, Weiss H, Karita E, Priddy F, Fuller L et al: J Womens Health (Larchmt) 16:1017–1027, 2007). In the absence of PMTCT, women who are HIV seropositive at the time of their first antenatal screening were assumed to have an average probability of transmitting the virus at delivery equal to 0.20 with the probability varying according to the mothers’ CD4 count (Bekker L-G, Black V, Myer L, Rees H, Cooper D, Mall S et al: South Afr J HIV Med 12:31–44, 2011). In the absence of PMTCT, women who are HIV seropositive at the time of delivery are assumed to be HIV transmission probability (Cooper D, Moodley J, Zweigenthal V, Bekker LG, Shah I, Myer L: AIDS Behav 13(Suppl 1):38–46, 2009). If the woman acquires HIV while breastfeeding, a higher transmission probability was assumed to apply during the acute phase that follows HIV acquisition reported (Cooper D, Harries J, Myer L, Orner P, Bracken H, Zweigenthal V: Soc Sci Med 65:274–283, 2007). PLHIVs who are initiated highly active ART (HAART) during pregnancy are assumed to have (p = 0.03), the probability of transmitting the virus to their infant at birth (Celum C, Wald A, Lingappa JR, Magaret AS, Wang RS, Mugo N et al: N Engl J Med 362:427–443, 2010). It was assumed that 50% of women, who have received positive test results, elect to formula feed, 45.6% initially practice exclusive breastfeeding (which is assumed to reduce the risk of transmission per month of breastfeeding), and the remaining practiced mixed feeding from birth, for a median duration of 8–10 months (French R, Brocklehurst P: Br J Obstet Gynaecol 105:827–883, 1998). In women who know themselves to be positive and elect to practice exclusive breastfeeding (EBF), the median duration of EBF is assumed to be 4 months, after which women either practice abrupt weaning or switch to mixed feeding (Gray RH, Li X, Kigozi G, Serwadda D, Brahmbhatt H, Wabwire-Mangen F et al: Lancet 366:1182–1188, 2005). If women receive “HAART” while breastfeeding, the monthly postnatal transmission risk is assumed to be reduced by 86% (Department of AIDS Control, Ministry of Family Welfare, Government of India: Annual report 2008–2009. http://nacoonline.org/upload/Publication/Annual_Report_NACO_2008-09.pdf. Accessed on 27 Feb 2010, 2008). If the mother does not receive HAART while breastfeeding, but the infant receives extended nevirapine prophylaxis, the rate of transmission is assumed to be reduced by 60% (Guthrie BL, Choi RY, Bosire R, Kiarie JN, Mackelprang RD, Gatuguta A et al: AIDS Behav 14:1066–1071, 2010).