Comparison of prevention of parent-to-child HIV transmission programme & national biennial HIV sentinel surveillance data for tracking HIV epidemic in India.

HIV sentinel surveillance (HSS) among antenatal women in India has been used to track the epidemic for many years. However, reliable tracking at the local level is not possible as ANC sentinel sites are limited in number and cover a smaller sample size at each site. Prevention of parent-to-child-transmission (PPTCT) programme data has a potential advantage due to better geographical coverage, which could provide more precise HIV case estimates; therefore, we compared HSS ANC data with PPTCT programme data for HIV tracking. Out of the 499 surveillance sites, where HSS and PPTCT programme was being conducted in 2015, 210 sites (140 urban and 70 rural) were selected using a stratified random sampling method. HSS (n=72,981) and PPTCT (n=112,832) data records were linked confidentially. The sociodemographic characteristics of HSS and PPTCT attendees were compared. HIV prevalence from HSS ANC was compared with the PPTCT programme data using Chi-square test. State- and site-level correlation of HIV prevalence was also done. Concordance between HSS and PPTCT HIV positivity was estimated using kappa statistics. The age distribution of HSS and PPTCT attendees was similar (range: 23 to 27 yr); however, HSS ANC participants were better educated, whereas PPTCT recorded a higher proportion of homemakers. The correlation of HIV prevalence between HSS and PPTCT was high (r=0.9) at the State level and moderate at the site level (r=0.7). The HIV positivity agreement between HSS ANC and PPTCT was good (kappa=0.633). A similar prevalence was reported across 26 States, whereas PPTCT had a significantly lower prevalence than HSS in three States where PPTCT coverage was low. Overall HIV prevalence was 0.31 per cent in HSS and 0.22 per cent in PPTCT (P<0.001). High-quality PPTCT programme data can provide reliable HIV trends in India. An operational framework for PPTCT-based surveillance should be pilot-tested in a phased manner before replacing HSS with PPTCT.