Preventing HIV

There may not be a vaccine (yet) for HIV. However, one can take a medication to prevent having HIV, especially if one is at risk for acquiring it (such as persons engaging in high-risk behavior or if they have partners who are HIV-positive). This is called Preexposure Prophylaxis (in short, PrEP). This is in contrast to Postexposure prophylaxis (in short, PEP), in which the medications are taken after a person has been exposed to HIV already. The US Public Health Service actually released a clinical practice guideline on PrEP in 2014. It urges clinicians to consider offering PrEP as an HIV prevention option to their patients at substantial risk of acquiring HIV infection. However, despite these, PrEP is still not very commonly employed. One hurdle may be that many clinicians are not comfortable with prescribing anti-retroviral medications. Also, even after getting a prescription for Truvada (the medication used to prevent HIV in PrEP), the patient still has to navigate the health system in order to get it, which includes asking his/her health insurance provider to cover the medication and coordinating with other patient assistance programs and deal with the co-pays, deductibles, and prior-authorization requirements. Luckily, in Austin, we have the Austin PrEP Access Project that helps people interested in PrEP in navigating the health system. More information can be found at

The Problem with Screening Everyone

In 2006, CDC recommended that patients in all health-care settings be tested for HIV. In 2013, the USPSTF followed suit and advised HIV testing for persons 15 to 65 years. However, as basic statistics would dictate, testing low risk population will lead to increased false positivity in test results. The increasing sensitivity of the fourth generation HIV tests can even worsen this. As the HIV testing recommendation above is getting applied by more and more health institutions and public health entities, the problem of high false positivity in low risk population arises. It is a very serious matter for a patient getting told what his/her HIV screening result is (it can be very anxiety-provoking). It is also a serious matter for public health as each positive HIV test can mean new case to investigate for Disease Intervention Specialists (DIS). It is therefore very important that providers explain to the patient the concept of positive predictive value of the test in the setting of low prevalence if the patient is of low risk of having HIV.