HIV/AIDS in the United States

One of the major collectors and distributors of data about the HIV/AIDS epidemic is the CDC. The CDC collects two sets of data to track the HIV/AIDS epidemic in the United States: results from HIV surveillance and results from AIDS surveillance.

HIV surveillance

Twenty-nine states and the US Virgin Islands have been reporting new HIV infections to the CDC since 1998. In more recent years, additional areas have joined the reporting system, facilitating the monitoring of HIV trends over time and better understanding of the behaviors that increase HIV infection risk in the United States and its territories (CDC, 2003, n.d.e). The HIV data collected by the CDC (such as those shown in the figure below) are statistically adjusted to take into consideration reporting delays.

Cases of HIV infection (not AIDS) by age at diagnosis through 2004—42 areas (CDC, n.d.e).

AIDS surveillance

AIDS diagnoses are reported to the CDC by all US states and territories. These data are statistically adjusted for reporting delays and are used to look at AIDS trends in the United States (CDC, 2003). For example, as the line marked by triangles shows in the figure below, the number of new AIDS cases (ie, AIDS incidence) has been decreasing since 1993. In 1993, approximately 80,000 adults and adolescents were diagnosed with AIDS. By 1998, that number had dropped by about 50%, to approximately 40,000 cases. Decreases in incidence were partly a result of better HIV prevention, such as organizations testing their blood supplies for HIV and individuals practicing safer sex. They also were in large part a result of the introduction of HAART in 1996. HAART interferes in the HIV reproductive cycle, making HIV less likely to reproduce in the body and lead to AIDS.

Number of AIDS cases, AIDS deaths, and people living with AIDS, 1985-2004, United States (CDC, n.d.a)

Discussion question: Surveillance data helps predict how much a disease will affect a specific population. Why is this particularly important in the case of HIV/AIDS populations?

Because HAART slows the progression of AIDS, its use also has contributed to a decrease in AIDS-related deaths and a corresponding increase in the number of people living with AIDS (ie, AIDS prevalence) (Osmond, 1998). As is seen in the graph line marked with circles in the figure above, in 1993 fewer than 150,000 people were living with AIDS in the United States. By 2003, US AIDS prevalence had increased to around 400,000 people.

The graph line marked with diamonds shows AIDS mortality—the number of people who died from AIDS in a given year. Mortality began to drop markedly after the introduction of HAART in 1996. New and more effective medications for opportunistic infections (infections that take advantage of the weakened immune systems of people with HIV) also may have contributed to this decrease.

Although new therapies for treating HIV/AIDS have been responsible for decreasing AIDS-related mortality, treating AIDS can be very complicated and difficult. People with HIV/AIDS often take many medications, and the appropriate dosage of these medications must be taken on a specific time schedule. Unfortunately, the medicines, although effective, sometimes have unpleasant side effects that may discourage people from taking them as prescribed. In addition, if not taken properly, HIV may become resistant to the medicines, meaning that the medicines no longer work as well. Thus, AIDS mortality may not continue to decrease until new and improved treatments are available.