To Contact Tracing... and Beyond!

To the Editor—We write to endorse and extend the thoughts of Nosyk et al on contact tracing [1], which we strongly agree is an opportunity to achieve additional public health goals, including diagnosis, treatment, and prevention of human immunodeficiency virus (HIV). We wish to make 2 points. First, in addition to HIV, we can consider testing and treatment for curable sexually transmitted infections (STIs), including chlamydia, gonorrhea, and syphilis. Social distancing during the coronavirus disease 2019 (COVID-19) pandemic may result in a temporary reduction of sexual partnerships [2] that could interrupt spread of STIs as well as HIV across those networks [3]. While elimination of STIs seems unrealistic, widespread testing and treatment for curable STIs during the current period of distancing could lead to a drop in STI prevalence that, in turn, could have long-term public health benefits. Such testing and treatment efforts could likewise be combined with contact tracing as described by Nosyk et al, but this may not be feasible in all settings because of stretched public health resources. However, home-based self-testing—and even self-treatment with support through telemedicine—may be an option. Home-based STI testing seems broadly acceptable in the United States [4] and is being explored [5] and indeed actively pursued [6] already. If circumstances prevent these strategies from being adopted, public health leaders and clinicians should strongly encourage people to obtain screening for HIV and STIs before considering sex with new partners in the postisolation period. This encouragement can also come from governmental and private entities, including nontraditional venues such as hook-up apps.

Second, Nosyk et al recommend HIV screening “focused on the geographic regions with the highest rates of new diagnoses,” but also seem to be proposing screening in people without apparent symptoms or indications. As such, it can be expected that the prevalence of infection will be extremely low; as a consequence, testing will be inefficient (ie, many assays used on negative individuals), and the positive predictive value of testing will be low. One method for improving both the efficiency and predictive value of testing is group testing, also known as pooling, which has been used with great success to detect acute HIV among antibody-negative blood samples [7] and blood spots [8], and more recently used for severe acute respiratory syndrome coronavirus 2 (eg, [9]). Group testing can greatly increase efficiency for a low-prevalence condition and—when errors of testing stages are independent—substantially increase positive predictive value as well, albeit with costs to sensitivity [10]. Such an approach, or another multistep screening approach such as administration of a risk questionnaire before blood testing, might be carefully and appropriately considered to improve the efficiency and utility of screening if Nosyk et al’s suggestions are pursued.

Notes

Financial support. This work was supported by the National Institute of Allergy and Infectious Diseases (grant numbers K01 AI122853 to J. L. M. and R01 AI138783 to S. M. J.).

Potential conflicts of interest. J. L. M. has consulted for Kaiser Permanente Northern California on a research grant from Gilead Sciences, outside the submitted work. All other authors report no potential conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.