News-Letter

Media Credit: Shiv Gandhi [Click to enlarge]

If the United States were to spend more on HIV prevention, would we see a subsequent decline in HIV infection rates?

That is the simple question posed by David Holtgrave of the Department of Health, Behavior, and Society in the Bloomberg School of Public Health, in a recent paper appearing in the American Journal of Preventive Medicine.

A statistical analysis of the available data on incidence rates for HIV, or human immunodeficiency virus, and government spending on HIV prevention appears to indicate that such spending does contribute to decreased incidence of infections.

Holtgrave analyzed trends between 1978, the year HIV/AIDS was first recognized in the United States, and 2006. In 1978, there were no reported cases of HIV infection in the country. By 1984, that number had reached 161,000.

Over the next several years, that number gradually leveled off and then declined. The reported rate of HIV incidence has remained steady at about 40,000 cases for every year since 2006.

This decline reflects, among other things, an ongoing public health campaign over the past two decades to raise awareness of HIV and to make testing and treatment more readily accessible.

Incidence refers to the number of people reported to be infected with HIV at any given time. This number is affected by the reporting methods used. Even today, many infected people likely remain untested, undiagnosed and unreported.

Government spending on HIV prevention is channeled primarily through the National Center for HIV, STD, and TB Prevention, part of the Centers for Disease Control and Prevention in Atlanta.

The U.S. government first began spending on HIV prevention in 1981, three years after the epidemic began. The actual annual budget has increased from $200,000 in 1981 to just under $720 million in 2006.

However, once adjusted for inflation, the CDC prevention budget has stayed relatively stagnant for over a decade. The greatest growth in spending occurred during the late 1980s as public awareness of the epidemic increased.

Holtgrave's analysis shows a strong correlation between spending and infection rates. Changes in both incidence and spending were most dramatic in the last few years of the 1980s, but the correlation holds to the present.

The analysis assumes that there should be a lag time of approximately one year between the appropriation of new funds and the time when they begin to show effects on HIV incidence rates.

A similar analysis performed several years ago on gonorrhea rates and spending on STD prevention revealed similar results.

The findings are significant because they suggest that, especially during the early years of HIV/AIDS in this country, government programs to reduce the size of the epidemic actually worked.

It is important to note that a statistical correlation does not prove that the spending actually caused decreased infection rates. Other factors, including increased public awareness about HIV and greater vigilance by doctors and local authorities, could also be linked to the declining infection rates.

The National Center for HIV, STD, and TB Prevention funds a variety of initiatives including counseling for at-risk populations, surveillance and epidemiological research, and support for local public-health authorities.

The CDC has set a goal of reducing HIV infection rates an additional 50 percent, to 20,000 cases, over the next few years. If the correlation predicted by Holtgrave's research holds, that goal may be difficult to achieve without additional funding.

Holtgrave wrote the paper with Jennifer Kates of the Kaiser Family Foundation, a non-profit research organization specializing in healthcare policy.

Save the date: lunar eclipse set for this Sat., March 3

This weekend you have a rare opportunity to witness one of the wonders of the natural world and to engage in some armchair astronomy. Saturday night, beginning at 5:44 p.m. EST, a total lunar eclipse will be visible from a sizeable portion of the globe, including the east coast of North America.

When considered in three dimensions, the simple elliptical orbits of the Earth around the Sun and the Moon around the Earth create complex patterns. An eclipse occurs when all three celestial bodies are lined up in a particular direction.

A lunar eclipse occurs when the Earth sits directly between the other two bodies. As a result, the Earth's shadow is cast on the Moon. The shadow creeps along the lunar surface over a period of several hours until totality is reached, at which time the Moon is completely submerged in darkness.

Because of the bending or refraction of light around the Moon, there is still a halo of light visible around the edges of the Moon, even at the height of totality. Also as a result of the scattering and bending of light, the eclipse might generate shades of yellow, orange or red as it progresses across the lunar surface.

Total lunar eclipses can occur anywhere from six months to more than three years apart. Partial lunar eclipses, in which only a small part of the Earth's shadow appears on the lunar surfance, are somewhat more common, occuring about twice each year. The next total lunar eclipse will occur on Aug. 27, 2007.

The eclipse should be easily visible from most of the globe. Unlike solar eclipses, a lunar eclipse occurs simultaneously throughout the entire viewing area. The downside of this is the fact that the eclipse will have already begun by the time the Moon has risen in the eastern United States.

You can expect to see totality from 5:44. when the Moon rises, until 6:58 p.m. The earth's shadow will slowly subside until it has fully cleared the Moon at 9:24 p.m. Try to get away from bright artificial lights. No special viewing equipment is necessary; unlike a solar eclipse, a lunar eclipse can be observed safely with the naked eye. Don't miss this!

--S.B.

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