In an early-morning announcement today, researchers reported that an experimental HIV (human immunodeficiency virus) vaccine effectively reduced the number of people who contracted the virus by nearly a third.

Tested in a U.S.-sponsored trial that involved more than 16,000 volunteers in Thailand, the vaccine was administered in six injected doses starting in 2006 to half of the group, and the other half received a placebo. Seventy-four people in the placebo group had contracted HIV by the end of the trial, whereas only 51 of the vaccinated group tested positive.* The injections consisted of two vaccines that had proven unsuccessful on their own: Sanofi-Aventis SA's ALVAC and VaxGen Inc.'s AIDSVAX.

The results came as a surprise to HIV-vaccine skeptics in the AIDS (acquired immunodeficiency syndrome) research field, whose numbers have increased after years of failed vaccine trials. "It's safe to say that the scientific community is caught off-guard," Mitchell Warren, director of the AIDS Vaccine Advocacy Coalition, told Bloomberg News. Before the announcement, Marie-Paule Kieny, director of the World Health Organization's Initiative for Vaccine Research, told the news service: "I don't think that there is a lot of expectation that the efficacy of this vaccine will be very high." A 2007 clinical trial of a vaccine made by Merck was stopped when researchers found that, in fact, more people who received the active vaccine (49) than the placebo (33) had contracted HIV.

Wild chimpanzees can become ill and die from a simian version of the AIDS virus, according to a paper to be published tomorrow in Nature (Scientific American is part of the Nature Publishing Group). The findings challenge long-held assumptions that chimps, our close relatives, could carry a simian version of HIV but not get sick from it.

The human immunodeficiency virus (HIV) found its way into people from a similar virus carried by monkeys called SIV (simian immunodeficiency virus). Researchers studying chimpanzee populations in the Gombe National Park—where Jane Goodall worked—have found that some chimps infected with a certain strain of SIV were indeed contracting a simian version of AIDS. Autopsies of some of the dead chimps revealed similar organ degeneration similar to that found in long-term human AIDS patients.

As the world frets about the swine flu virus, the scientists credited with discovering HIV urged governments and international organizations to redouble their commitment to the battle against AIDS.

Robert Gallo and Luc Montagnier, whose roles in identifying the viral cause of AIDS have been disputed over the years, came together Friday to commemorate the 25th anniversary of their discovery with a global call to action.

Acknowledging the public’s preoccupation with the unfolding H1N1 pandemic, Gallo said, "Don't forget we have a known problem…a known deadly epidemic." Some 175,000 people die from AIDS every month—about the same number of lives claimed by the 2004 Asian tsunami, he told the audience gathered at the National Press Club in Washington.

Pharmaceutical giants GlaxoSmithKline (GSK) and Pfizer said today that they're creating a company dedicated to developing HIV medications. The unusual arrangement will give London-based GSK 85 percent equity and New York's Pfizer the remainder.

The companies said in a statement that the merger would "be more sustainable and broader in scope than either company's individually," giving the new partnership 19 percent of the HIV drug market through a combined portfolio of 11 already-available meds and six candidates in development. The idea is that the $2.4 billion in sales generated from the marketed drugs will keep the development pipeline moving, the companies said.

The U.S. President's Emergency Plan for AIDS Relief (PEPFAR) has saved at least a million lives in sub-Saharan Africa but does not appear to have curbed the epidemic, a new study suggests.

"PEPFAR has been on the whole an extremely successful program," says study co-author Eran Bendavid, an infectious disease and health policy researcher at Stanford University in Palo Alto, Calif. But, he says it's unclear how successful it was at preventing new cases of HIV. 

In May 2003, President George W. Bush signed legislation authorizing PEPFAR, a commitment by the U.S. to spend $15 billion over five years to prevent HIV/AIDS and treat victims in Africa, Asia, and the Caribbean -- "the largest commitment by any nation to combat a single disease in history," according to the program's official Web site.

Teens in South Africa have found a new use for efavirenz (brand name Stocrin in South Africa and Sustiva in the U.S.), an antiretroviral drug that prevents HIV from making copies of itself in the body. Instead of using efavirenz as it was intended – to keep the AIDS virus at bay – kids are crushing the pills and smoking the powder to get high, ABC News reports.

When taken as prescribed, efavirenz can cause side effects, including drowsiness and vivid, colorful dreams, but when smoked, it induces hallucinations and is highly addictive. "Once you've first started, there's no turning back," a 17-year-old addict told ABC News.

Circumcision is often touted for its potential health benefits: reduced risk of urinary tract infections for baby boys, and lower rates of HIV in teens and men. Now a new study shows that it may also cut a man's chances of contracting two more common, incurable sexually transmitted diseases.

Two randomized, controlled trials in Uganda involving 5,534 men found that those who underwent circumcision as adults were 25 percent less likely to become infected with herpes and more than 30 percent less likely to catch human papillomavirus (HPV) than their uncircumcised peers. (Eight percent of circumcised men and 10 percent of uncircumcised men in the study caught herpes; 18 percent of circumcised men and 28 percent  of uncircumcised men contracted HPV.) The research published today in the New England Journal of Medicine didn't, however, find that getting circumcised reduced the risk of contracting syphilis. Previous research has shown that circumcision reduces a man's risk of acquiring HIV by as much as 60 percent.

Public health advocates have long touted the female condom as a way for women to protect themselves against HIV, especially if their partner didn’t want to use a male prophylactic. But while the female condom has been distributed around the world over the last 16 years, it may make a bigger splash if it's cheaper. 

The polyurethane sheath, originally approved in 1993, costs anywhere from $2.80 to $4 a piece – a steep price for women in developing countries to whom the condom was marketed (never mind those in the U.S., who could pick up several of the male version for not much more than that — or for free), Reuters reports. That may change, now that the Food and Drug Administration (FDA) has approved a next-gen female condom made of synthetic nitrile (a form of rubber) that costs less money for its manufacturer, the Chicago-based Female Health Company, to make. The cost of the new female condom, FC2, could fall to around 60 cents per device for health groups and government agencies that want to buy them, according to the newswire. Male condoms typically cost around 50 cents each.

The amount of HIV infection among people over 50 is “surprisingly high,” World Health Organization (WHO) officials say, and despite much speculation about why, there’s little definitive information that might shed light on the trend.

“HIV prevalence and incidence in the over–50-year-olds seem surprisingly high and the risk factors are totally unexplored,” according to an editorial in the March Bulletin of the World Health Organization. “Understanding the epidemiology of HIV infection in older individuals can lead to interventions to make these years safer and more enjoyable.”

In 2005 people 50 and older accounted for 15 percent of the new HIV/AIDS diagnoses in the U.S. and 24 percent of people living with the virus, according to the U.S. Centers for Disease Control and Prevention (CDC). These figures are up 17 percent since 2001.

Is Pres. Obama getting closer to filling a key health post? The role of Food and Drug Administration (FDA) chief is down to two candidates, the Washington Post says in an unsourced report: Baltimore Health Commissioner Joshua Sharfstein and former New York City Health Commissioner Margaret Hamburg. Sharfstein's name has been floated repeatedly since Obama was elected, and Hamburg's surfaced early this month.