Lower levels of HIV-2 than HIV-1 in the female genital tract: correlates and longitudinal assessment of viral shedding.
BACKGROUND
The differing magnitude of the HIV-1 and HIV-2 epidemics is likely a consequence of differing transmission rates between the two viruses. Similar to other sexually transmitted pathogens, risk of HIV-1 and HIV-2 transmission is likely associated with the presence and amount of HIV in the genital tract. Thus, understanding patterns of, and risk factors for HIV genital tract shedding is critical to effective control of HIV transmission.


METHODS
We evaluated HIV DNA and RNA detection in cervicovaginal specimens among 168 HIV-1 and 50 HIV-2-infected women in Senegal, West Africa. In a subset of 31 women (20 with HIV-1, 11 with HIV-2), we conducted a prospective study in which cervicovaginal specimens were taken at 3-day intervals over a 6-week period.


RESULTS
We found significantly lower rates and levels of HIV-2 RNA (58% shedding; 13% with >1000 copies/ml) in the female genital tract than HIV-1 RNA (78% shedding; 40% with >1000 copies/ml) (P = 0.005 and 0.005, respectively), and shedding correlated with plasma viral load irrespective of virus type (odds ratio = 1.9, 95% confidence interval = 1.3-2.8 for each log10 increase in HIV viral RNA). Plasma viral load, not HIV type, was the strongest predictor of genital viral load. Over 80% of closely monitored women, regardless of HIV type, had at least intermittent HIV RNA detection during every 3-day sampling over a 6-week time period.


CONCLUSIONS
These data help in explaining the different transmission rates between HIV-1 and HIV-2 and may provide new insights regarding prevention.
Hawes
Stephen E
SE
Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, Seattle, Washington 98103, USA. hawes@u.washington.edu
Sow
Papa Salif
PS
Stern
Joshua E
JE
Critchlow
Cathy W
CW
Gottlieb
Geoffrey S
GS
Kiviat
Nancy B
NB
D000328:Adult; D003430:Cross-Sectional Studies; D004279:DNA, Viral / Q000378:metabolism*; D005260:Female; D005836:Genitalia, Female / Q000821:virology*; D015658:HIV Infections / Q000517:prevention & control / Q000635:transmission* / Q000821:virology; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D015498:HIV-2 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D011446:Prospective Studies; D012367:RNA, Viral / Q000378:metabolism*; D012307:Risk Factors; D012675:Senegal; D019562:Viral Load; D017201:Virus Shedding
D004279:DNA, Viral; D012367:RNA, Viral