[Question #8213] Old and new window period
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47 months ago
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Dear Doctors,
my wife had an exposure back in 2017: unprotected vaginal intercourse with ejaculation inside. The partner HIV status was unknown.
Reading your old answer (I cannot remember if it was here or in your previous site), she decided to take an HIV Ab/Ag test at 4th weeks. The test came back negative and she forgot this event.
It seems however that your new guidelines suggest to have a conclusive test at 6 weeks.
Does she need to retest because her previous test was not conclusive?
She is now in a very difficult moment, she is taking SSRIs and I do not want to scare her.
Thank you very much
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Edward W. Hook M.D.
47 months ago
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Welcome to our forum and thanks for your question. The change in the recommended time to conclusive results for combination HIV antigen/antibody tests created some confusion. I’ll be glad to explain. Until several years ago most experts including us, used the four week interval to define the time required to get conclusive test results using combination tests. Subsequently, the CDC published revised recommendations apparently based on a very small number of persons who had converted their tests in the intervals between four and six weeks. Seroconversion during the 4 to 6 week interval is very, very rare. Neither of us on the forum has ever seen or heard of a person in whom this has occurred. Nonetheless, honoring the CDC’s conservative recommendations, we now use that interval as well. I estimate that over 99% of seroconversion occur before the four week time period
Regarding your wife’s exposure, the likelihood of her having acquired HIV is vanishingly rare and given the situation I see no reason for heading to her anxiety. The HIV status of her partner was unknown and most people do not have HIV. Even if her partner had untreated HIV at the time of the exposure, her risk from a single episode of vaginal intercourse would be less than one infection for every 1000 exposures. Subsequently her testing it for weeks would have eliminated 99% of the chances that she would have been infected. Putting all of these variables together – the unknown status of the partner, the low risk of infection following in an exposed exposure, and her -4 week test results, the chances that she acquired HIV are less than one in tens of millions. I would not worry further and in the situation same situation would not feel the need for additional testing.
I hope this information is helpful. EWH
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