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Window Period for Occupational Exposures
#13270 - 12/06/00 11:14 AM
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Taken from a report on HIV exposure in a health care setting:
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available, 81% experienced a syndrome compatible with primary HIV infection a median of 25 days after exposure (CDC, unpublished data, 1998).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 (34). 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 (35).
Three instances of delayed HIV seroconversion occurring in HCWs have been reported; in these instances, the HCWs tested negative for HIV antibodies greater than 6 months postexposure but were seropositive within 12 months after the exposure (36,37; J.L. Gerberding, San Francisco General Hospital, unpublished data, May 1997).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associated with simultaneous exposure to hepatitis C virus (HCV) (37; J.L. Gerberding, San Francisco General Hospital, unpublished data, May 1997). In one case, co-infection was associated with a rapidly fatal HCV disease course (37); however, it is not known whether HCV directly influences the risk for or course of HIV infection or is a marker for other exposure-related factors.
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PVS
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Reged: 09/19/00
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Posts: 280
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This is why HCW are tested out to a year in occupational exposures.
It is also advisable if you think that you have been exposed to do a complete STD and Hepatitis panel to determine if you have other diseases that may slow down antibody production.
Read Dr. Dietrich's expert forum on Hepatitis and HIV and you will see that there are quite a few folks who are poz and co-infected with HCV.
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The only thing that this proves is seroconversion can take over 6 months. All the information I have found also states that around 95% of people will convert by 6 months. I don't believe 6 months is 99.9% accurate. And I do think more people will end up postive after 6 months. Why is it that they continue to tests people with know exposures for out to a year? Because their is a real possiblity of converting after 6 months.
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PVS
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Reged: 09/19/00
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Posts: 280
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Duh. No one said you couldn't have your own opinion on the matter of the window period. Keep testing out to a year..perhaps two even. Just don't go surfing the web looking for outlier cases to make your case stronger on delayed seroconversions. They DO happen but in RARE instances where the individuals had co-infection with another disease.
This proves that point that if you look hard enough to find ammunition for an argument that you will find it. Take note the data that you provided earlier remains unpublished. Also, you fail to mention that these HCW had DEFINITE exposure to HIV-tainted blood which found its way to their bloodstream. Not a "possible" exposure in relation to HIV via a partner of uknown status. Even in sexual exposures the average time suggested for testing is 16-20 weeks and that is already extremely conservative. Why do I know this? I got the answer from a Dr. at Johns Hopkins.
Believe what you want, I still trust the ID docs. Have a great time obsessing.
PVS
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One other thing that is mentioned here and I also read from a John Hopkins study. Health care workers that have been exposed are immediately put on an aggressive antiviral therapy as a precaution. There is one sited case of an HCW from a needle stick that went through this scenario.
She was put on an antiviral therapy within hours of exposure and this continued for a good period of time. At the end of the therapy she tested negative, undetectable. 12 weeks after she stopped the therapy she went through what they called a classic case of seroconversion - high spiked fever, swollen glands, sore throat, weight loss.
I think the total amount of time elapsed from exposure to seroconversion was about 5-6 months. Doctors believe that the precautionary antiviral treatment delayed her seroconversion.
For what its worth.
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I don't believe 5 out of 100 is rare when talking about HIV.
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Three things I would note from this post:
1) You seem to derive your information from mostly old data - circa 1997 - 1998. I would like to know when the "recent" HCW data analysis took place. In all probability this testing was done with 1st & 2nd generation Elisa test methods which are less sensitive and introduce a time delay in measurable sero-conversion.
2) Mode of transmission is mostly needle-stick. Syringes which have small traces of blood and the virus contained by the blood may be weakened if it has been out of the host for several minutes or more. This may have led to a low viral set-point, less efficient transmission and delayed conversion.
3) Health care workers are exposed to many viruses ther-fore their sero-conversion may differ to that of the general public (i.e. they have a higher chance of having immune system issues to begin with).
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Hey are you a healthcare worker? If you have been exposed then immediately begin PEP 72 hours after exposure.
If it was a sexual exposure. Get a grip and get tested at 12 weeks.
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Do you think being infected with HPV would cause a delay in HIV antibody production?
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NO. If you don't believe me, surf in the expert forum.
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