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Q&A
Explanation of HIV diagnoses increase vs. new infections decrease
0:50:11
ยท
130 sec
Council Member Schulman asks about the 7.6% increase in HIV diagnoses but 17% decrease in new HIV infections. Sarah Braunstein explains the divergence:
- HIV diagnoses are actual first positive tests reported to the surveillance system
- HIV incidence (new infections) is estimated using a CDC methodology based on CD4 count data
- The divergence suggests more people with long-standing undiagnosed infections were detected
- The estimated number of new HIV acquisitions appears to be decreasing
Key points:
- Incidence estimation provides insight into current HIV acquisition trends
- The divergence will be monitored over time to identify long-term trends
- The data suggests improved detection of previously undiagnosed cases
Lynn C. Schulman
0:50:11
In your 2023 annual report, you noted a seven point six increase percent increase in the number of HIV diagnoses in New York City from 2022 to 2023, but a seventeen percent decrease in new HIV infections.
0:50:24
One is how did you determine there had been a seventeen percent decrease in new HIV infections despite the increase in diagnoses, and can you explain the divergence in the two statistics?
Sarah Braunstein
0:50:35
Sure.
0:50:35
That's thank you for that question.
0:50:36
Mhmm.
0:50:37
So yes.
0:50:38
So HIV diagnoses are actual first positive tests reported to our surveillance system as I just noted.
0:50:47
HIV incidence, where which is actually the number of of newly acquired infections during a period of time, these are not necessarily diagnosed and so are not, you know, known, through a positive test.
0:51:01
So instead, we and other health department jurisdictions across the country estimate HIV incidence using a methodology, an analytic methodology, developed by the Centers for Disease Control and Prevention.
0:51:13
And that methodology uses CD four count or a marker of immune status, data that we do get in surveillance to essentially estimate, among people reported to the surveillance system when they may have acquired their HIV infection.
0:51:26
And that number is really powerful because it gives us a better sense even than the number of new diagnoses, of the sort of leading edge, the current, you know, even more complete status of HIV acquisition in the city in a given year.
0:51:39
So you're right to point out that, we did see this, divergence in in a single year between the number of new diagnoses and the estimated number of HIV infections.
0:51:49
And what we you know, no one year, no no one data point makes a trend, so this is something we'll certainly monitor over time to see what direction this takes.
0:51:58
But what we, you know, hypothesized around these two numbers together is that that new diagnosis number reflects that we did, in fact, importantly, detect more people who had been living with an HIV infection for a longer period, but were not yet diagnosed.
0:52:14
And that it looks like so far that the actual number or estimated number of people acquiring HIV is going down.