Increasing sero-discordancy among young HIV infected pregnant women from India: a likely pointer of changing transmission dynamics.

The flat-lining of HIV incidence in India has raised concerns about the presence of emerging risk groups. As HIV prevalence among pregnant women is reflective of the situation in general population, its closer scrutiny provides valuable insights about the evolving epidemic. The present study assesses temporal trends of sero-discordance (where woman is HIV infected and husband is uninfected), among pregnant women living with HIV (pWLHIV) from India. Data of program for prevention of parent to child transmission of HIV was analyzed. Statistical analysis was done using Cochrane-Armitage trend test and logistic regression. Of the 1209 currently married pWLHIV, 302 (25%) were sero-discordant. The proportion increased from 16% in 2007 to 36% in 2016-17 (p = 0.000). The likelihood of sero-discordance was higher for women aged 18-20 (OR: 2.68, CI: 1.30-5.83) and 21-23 (OR: 1.98, CI: 1.01-4.15) years compared to 36-40 years; and for primi-parous women (OR: 1.84, CI: 1.31-2.58) compared to women pregnant for second/third time. The findings are indicative of changing HIV transmission dynamics. Steeper rise in sero-discordance in younger women implies an increasing risk of HIV in unmarried women population. A better understanding of HIV specific vulnerabilities of young women, married and unmarried, is warranted.