Declining HIV prevalence among young pregnant women in Lusaka, Zambia.

OBJECTIVE HIV prevention has been ongoing in Lusaka for many years. Recent reports suggest a possible decline in HIV sero-incidence in Zambia and some neighbouring countries. This study aimed to examine trends in HIV seroprevalence among pregnant and parturient women between 2002 and 2006. METHODS We analysed HIV seroprevalence trends from two Lusaka sources: (i) antenatal data from a city-wide programme to prevent mother-to-child HIV transmission, and (ii) delivery data from two anonymous unlinked cord-blood surveillances performed in 2003 and again in 2005-2006, where specimens from > 97% of public-sector births in each period were obtained and analysed. FINDINGS Between July 2002 and December 2006, the Lusaka district tested 243 302 antenatal women for HIV; 54 853 (22.5%) were HIV infected. Over this period, the HIV seroprevalence among antenatal attendees who were tested declined steadily from 24.5% in the third quarter of 2002 to 21.4% in the last quarter of 2006 (P < 0.001). The cord-blood surveillances were conducted between June and August 2003 and again between October 2005 and January 2006. Overall HIV seroprevalence declined from 25.7% in 2003 to 21.8% in 2005-2006 (P = 0.001). Among women < or =17 years of age, seroprevalence declined from 12.1% to 7.7% (P = 0.015). CONCLUSION HIV seroprevalence appears to be declining among antenatal and parturient women in Lusaka. The decline is most dramatic among women < or = 17 years of age, suggesting a reduction in sero-incidence in this important age group.