HIV Seroconversion in HCWs
Data on the timing and clinical characteristics of seroconversion in HIV exposed HCWs are limited by the infrequency of infection following occupational exposure, variations in postexposure testing intervals, and differences over time in the sensitivity of HIV-antibody testing methods. Among the HCWs with documented seroconversions reported to CDC for whom data are available, 81% experienced a syndrome compatible with primary HIV infection a median of 25 days after exposure (CDC, unpublished data, 1998). In a recent analysis of 51 seroconversions in HCWs, the estimated median interval from exposure to seroconversion was 46 days (mean: 65 days); an estimated 95% seroconverted within 6 months after the exposure. These data suggest that the time course of HIV seroconversion in HCWs is similar to that in other persons who have acquired HIV through nonoccupational modes of transmission. Three instances of delayed HIV seroconversion occurring in HCWs have been reported; in these instances, the HCWs tested negative for HIV antibodies after more than 6 months postexposure but were seropositive within 12 months after the exposure (J.L. Gerberding, San Francisco General Hospital, unpublished data, May 1997). DNA sequencing confirmed the source of infection in one instance. Two of the delayed seroconversions were associated with simultaneous exposure to hepatitis C virus (BCV) (J.L. Gerberding, San Francisco General Hospital, unpublished data, May 1997). In one case, coinfection was associated with a rapidly fatal BCV disease course; however, it is not known whether BCV directly influences the risk for or course of HIV infection or is a marker for other exposure-related factors.