Rapid HIV Test Has High False-Positive Rate, Risk of Fractures Higher in HIV-Infected Patients, Herpes Drug May Help Control AIDS Virus

October 2, 2008

An assessment of rapid HIV testing offered in emer­-gency department (ED) settings found the OraQuick ADVANCE Rapid HIV-1/2 Antibody Test produced a high rate of false-positives (Reuters. August 5, 2008).

Rapid HIV Test Has High False-Positive Rate
An assessment of rapid HIV testing offered in emer­-gency department (ED) settings found the OraQuick ADVANCE Rapid HIV-1/2 Antibody Test produced a high rate of false-positives (Reuters. August 5, 2008). Between February and October 2007, 849 adults who visited the emergency department at Boston’s Brigham and Women’s Hospital consented to rapid HIV testing, reported Dr Rochelle P. Walensky and coauthors. Of 39 patients with reactive results, 31 agreed to confirmatory testing and just 5 proved to be HIV-infected.

Among these initially positive patients, 13 of the 26 shown to be HIV-negative had indeterminate Western blot results, and 1 had an initial HIV RNA level in the detectable range. All 26 uninfected patients had a nonreactive serum enzyme-linked immunoassay. According to the researchers, “the estimated prevalence of newly identified HIV infection was 0.6%, which supports continued screening in the emergency department in compliance with the CDC guidelines.”

As a result of false-positive rates being considerably higher than suggested by the test’s manufacturer, the authors recommend the “addition of HIV RNA testing to the confirmation algorithm for rapid HIV screening tests in the United States.” The authors continued, “It is critical that health care providers be appropriately trained to assist patients in interpreting test results and facilitate appropriate follow-up.”

“Patients go to acute-care settings when they develop symptoms of acute HIV infection,” said Drs Christopher D. Pilcher and C. Bradley Hare in a related editorial. “Acute HIV infection is the most infectious stage of HIV disease and is, consequently, a public health emergency in which sexual and injection partners can be protected from the high risk of infection if HIV is promptly diagnosed and patients are counseled,” the San Francisco General Hospital physicians said. Because false-positive results will occur, “acute-care settings must have standardized confirmatory testing and quality assurance monitoring programs,” Pilcher and Hare stressed.

The report of the study and the editorial were published in the Annals of Internal Medicine (Walensky RP, Arbelaez C, Reichmann WM, et al. Revising expectations from rapid HIV tests in the emergency department; and Pilcher CD, Hare CB. The deadliest catch: fishing for HIV in new waters. Ann Intern Med. 2008;149:153-160 and 204-205, respectively). [CDC HIV/Hepatitis/STD/TB Prevention News Update, Tuesday, August 19, 2008]

Risk of Fractures Higher in HIV-Infected Patients
Bone fracture prevalence is higher among HIV-positive patients than among HIV-negative patients, according to a new study (Hoban R. Voice of America. September 9, 2008). Dr Steven K. Grinspoon of Harvard University and Massachusetts General Hospital, Boston, and colleagues examined a large database at the hospital. The database included 8525 HIV-positive and 2,208,792 HIV-negative persons who made at least 1 inpatient or outpatient visit to the facility between October 1, 1996, and March 21, 2008.

The prevalence of fracture in the two patient groups was evaluated, and the overall prevalence of bone fractures was 61% higher among the HIV-positive patients. Grinspoon said this proved to be true for men and wom­en, and minority and nonminority patients. Most of the HIV-infected patients were taking antiretrovirals. Grinspoon said it remains unknown why the HIV patients were more likely to suffer broken bones. “Is it the HIV virus? Is it the medicines that are associated with HIV, that patients take for that? Is it some other mechanism? We simply don’t know,” he said.

In parts of the world where antiretrovirals are largely unavailable, Grinspoon said the risk of fractures might be as great or greater than for patients in the study population, even though the treatment-naive patients might not live to ages where fractures are more common. “Weight and nutrition is a huge factor for bone loss in any set of patients, HIV [or] not. And generally patients are better nourished here as opposed to developing countries where patients can be very, very thin and wasted. So there may be even more of a problem with bone density and fractures in those populations,” Grinspoon said.

The report was published in the Journal of Clinical Endocrinology & Metabolism (Triant VA, Brown TT, Lee H, Grinspoon SK. Fracture prevalence among human immunodeficiency virus (HIV)-infected versus non-HIV- infected patients in a large US healthcare system. J Clin Endocrinol Metab. 2008;93:3499-3504). [CDC HIV/Hepatitis/ STD/TB Prevention News Update, Wednesday, September 10, 2008]

Herpes Drug May Help Control AIDS Virus
An inexpensive, generic treatment used against herpesvirus can also lower HIV viral load, researchers reported Wednesday at the International AIDS Conference in Mexico City (Maggie F. Reuters. September 11, 2008). However, acyclovir works against HIV only in tissues that are also infected with herpesvirus. The findings could help explain why some studies have shown that patients taking acyclovir have a lower HIV viral load, while in several high-profile experiments the drug failed to prevent HIV infection.

The herpesvirus changes acyclovir into a form that works against HIV, said study co-leader Dr Leonid Margolis of the National Institute of Child Health and Human Development, Bethesda, Md. The drug does not become active until it encounters a herpesvirus, usually herpes simplex virus type 2, the most common cause of genital herpes. The virus completes a chemical reaction called phosphorylation, turning acyclovir into an active compound. Margolis thinks he knows why acyclovir did not pan out in preventing HIV: the prevention studies were trying to completely suppress herpesvirus. “If you suppress herpes, HIV also goes down,” he said. “If you suppress herpesvirus completely, there is nothing to phosphorylate.” Future studies would be needed to test whether lower or more infrequent acyclovir doses might be more effective, Margolis added.

A patient does not have to be infected with herpes simplex virus type 2 to benefit, because infection with any herpesvirus could work, including the nearly universal childhood infection called roseola. Margolis said his team hopes to find better ways to use acyclovir against HIV, perhaps including it in a microbicide. Acyclovir might also be used to strengthen an HIV drug cocktail, he said.

The report was published in Cell Host & Microbe (Lisco A, Vanpouille C, Tchesnokov EP, et al. Acyclovir is activated into a HIV-1 reverse transcriptase inhibitor in herpesvirus-infected human tissues. Cell Host Microbe. 2008;4:260-270. doi:10.1016/j.chom.2008.07.008). [CDC HIV/Hepatitis/STD/TB Prevention News Update, Thursday, September 11, 2008]

New CDC Study on Spread of HIV in US
A highly detailed CDC analysis of HIV incidence in the United States found that in 2006, the disease continued to affect men who have sex with men (MSM) more than any other group. MSM represented the most new infections among white, black, and Hispanic populations. Most infected women acquired HIV heterosexually, with black women particularly at risk (Harris G. New York Times. September 12, 2008).

Among MSM, the CDC found that white and minority MSM tended to become HIV-infected at different times in their lives. Most new infections among black and Hispanic MSM were in those aged 13 to 29 years, while among white MSM, most new infections were in those aged 30 to 39 years. Among younger MSM, the number of new infections for blacks was 1.6 times that seen for whites and 2.3 times the number for Hispanics. Male-to-male sex accounted for 72% of new infections among males, including 81% of infections among whites, 63% among blacks, and 72% among Hispanics.

Among females, 80% of new infections were acquired through high-risk heterosexual sex. HIV incidence for black females was 14.7 times the rate for white females. Women and girls accounted for 27% of all new infections.

Of the new HIV infections in 2006, 46% occurred among blacks, although blacks constitute about 12% of the US population. The highest rates of new infections occurred among black males and females (at 115 cases and 55.7 cases per 100,000 population, respectively).

CDC researchers said that 80% of homosexual and bisexual men in 15 cities surveyed had not been reached by effective HIV prevention efforts. The CDC hopes that the data, including those regarding the race, gender, sexuality, and age of persons now acquiring HIV, will help direct future prevention efforts. Officials at the agency said HIV screening programs need to be expanded, and prevention programs need to better target those at risk.

The report was published in Morbidity and Mortality Weekly Report (Centers for Disease Control and Prevention. Subpopulation estimates from the HIV incidence surveillance system-United States, 2006. MMWR. 2008; 57:985-989). [CDC HIV/Hepatitis/STD/TB Prevention News Update, Friday, September 12, 2008]

Global AIDS Prevention Gives Short Shrift to Gays

Although the number of HIV infections among men who have sex with men (MSM) is rising in many countries, UNAIDS figures show that in 2006, less than 1% of the $669 million spent globally on HIV prevention targeted these men (Watson J. Associated Press. August 9, 2008). This is the smallest proportion of money targeting any at-risk population. Many MSM insist they are not gay, and many governments deny the existence of homosexuality.

During the opening ceremony of the 17th International AIDS Conference in Mexico City, UN Secretary-General Ban Ki-moon called on other countries “to follow Mexico’s bold example and pass laws against homophobia.” In 2003, Mexico banned discrimination based on sexual orientation, and it has opened clinics labeled homophobia-free. A national advertising campaign includes radio spots in which mothers talk about accepting their gay sons.

Jorge Saavedra, who is HIV-positive and heads Mexico’s AIDS prevention program, publicly declared his homosexuality for the first time at the conference, drawing loud applause from attendees. His department has earmarked 10% of its $12 million budget toward HIV prevention among MSM.

Data from 128 countries collected by the Foundation for AIDS Research (amfAR) show that MSM are 19 times more likely to be HIV-infected than the general population. In Mexico, MSM are 109 times more likely to be infected. Kevin Frost, the foundation’s CEO, said Thailand-for years lauded as an example for its massive condom-promotion efforts-is now seeing among MSM “an emerging epidemic of really unbelievable proportions.” HIV prevalence among Thai MSM is now more than 15%, compared with 1.4% in the general population.

“This fight needs to be driven by epidemiologists,” not only for the sake of human rights, but for the sake of public health, said Chris Beyrer, director of the Center for Public Health and Human Rights at the Johns Hopkins University. “It’s a virus, so you need to put the money where the virus is,” he said. [CDC HIV/Hepatitis/STD/TB Prevention News Update, Tuesday, August 12, 2008]