There are different ways to define the end of an HIV epidemic; all of them involve drastic declines in new infections in key populations. Here are a few terms you might need to know in order to understand common objectives and targets for EtE plans:
Prevalence: HIV prevalence refers to the number of people living with HIV at a specific point in time.[i] Ever since effective treatment for HIV was developed, this number has continued to rise due to decreased mortality and ongoing new infections. The central objective of EtE plans is to decrease prevalence while continuing to improve health outcomes for people living with HIV. “Bending the curve” on prevalence would effectively mean an end to epidemic levels of new HIV/AIDS cases. We do this by dramatically reducing incidence (see below).
Incidence: HIV incidence is the number of new HIV infections in a population during a certain time period.[ii] In order to reach our EtE goal of reducing prevalence for the first time since effective treatment became available, we need to dramatically reduce incidence.
New Diagnoses: The number of people who have received a confirmed HIV positive diagnosis in a given period. This is NOT the same as incidence; new diagnoses may be higher, lower, or equal to incidence depending on testing rates in key populations. Determining targets for new diagnoses for EtE is tricky; incidence estimates are a better option whenever they are available. When new diagnoses are being used for EtE targets, they should be tied to testing rates; a decline in new diagnoses could mean new infections are going down, or it could mean that we’re not doing enough testing of key populations.
Morbidity: Refers to having a disease or a symptom of disease, or to the amount of disease within a population.[iii] EtE initiatives seek to ensure that HIV-related morbidity – notably opportunistic infections and cancers associated with AIDS – is drastically reduced.
Mortality: Death. EtE initiatives seek to ensure that people living with HIV do not have higher mortality rates than the general population.
Epidemic: Refers to an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area.[iv] With HIV, we may say that the epidemic is continuing so long as prevalence continues to increase. With most EtE plans, we seek to reduce incidence so much that prevalence stops increasing.
In New York, the goal is for new infections to be reduced from around 3,000 per year in 2015 to no more than 750 per year by 2020; this would “bend the curve” on the number of people living with HIV/AIDS in the state, which has been consistently rising since effective HIV treatment became available in 1996.
Similarly, in Houston, EtE advocates are calling for the number of new HIV cases to decrease by half over five years, from 1,200 to 600 infections per year.[vi]
But ending the epidemic isn’t just about reducing new HIV infections. It is also an opportunity to end AIDS and improve health outcomes among people currently living with the virus. EtE strategies therefore aim to maximize the number of individuals who learn their diagnosis as soon as possible after infection and are immediately linked to expert and culturally competent care and services, including state-of-the-art HIV treatment.
This is not the same as an absolute end, or elimination, of HIV/AIDS, which would require a cure for those of us living with the virus and a vaccine for a sustainable end to the epidemic. Indeed, with promising research moving forward, such as the HIV Vaccine Trial Network’s 702 vaccine study and increased understanding of broadly neutralizing antibodies, it is more important than ever for advocates to ensure that the US government and the pharmaceuticals industry remain committed to vaccine and cure research. Our current EtE efforts merely affirm that we can end epidemics with the tools we have right now while we continue to advocate for a cure and a vaccine for HIV/AIDS.
[i] World Health Organization. HIV/AIDS: Definition of Key Terms [Internet]. 2017 (cited 2017 October 02). http://www.who.int/hiv/pub/guidelines/arv2013/intro/keyterms/en/.
[ii] World Health Organization. HIV Incidence [Internet]. 2017 (cited 2017 October 13). http://www.who.int/diagnostics_laboratory/links/hiv_incidence_assay/en/.
[iii] National Institutes of Health (U.S.). NCI Dictionary of Cancer Terms [Internet]. (cited 2017 October 13). https://www.cancer.gov/publications/dictionaries/cancer-terms?cdrid=44514.
[iv] Centers for Disease Control and Prevention (U.S.). Principles of Epidemiology in Public Health Practice, Third Edition. An Introduction to Applied Epidemiology and Biostatistics [Internet]. 18 May 2012 (cited 2017 October 13). https://www.cdc.gov/ophss/csels/dsepd/ss1978/lesson1/section11.html.
New York State Department of Health. Ending the AIDS Epidemic in New York State [Internet]. Revised 2017 May (cited 2017 July 26). https://www.health.ny.gov/diseases/aids/ending_the_epidemic/.