Abstract
HIV AND AIDS
HAART Decreases Risk of AIDS-Related Cancers
While HIV infection is associated with an increased risk of certain cancers that define clinical AIDS, including Kaposi's sarcoma (KS), non-Hodgkin lymphoma (NHL), and cervical cancer, highly active antiretroviral therapy (HAART) use decreases the risk of KS and of both systemic NHL and primary central nervous system (CNS) NHL, according to the findings of a recent study. Using matched statistics from the San Francisco AIDS Registry and the California Cancer Registry, researchers were able to control for calendar period and other confounding factors and to assess directly the impact of HAART use by individuals on their risk of and survival associated with these AIDS-related cancers. Whereas both HAART and a more recent timeframe were independently and significantly associated with a reduced risk of KS, only HAART and not calendar period was significantly linked to a decreased risk of NHL and CNS NHL. Furthermore, the study showed increased KS survival time with HAART, but no similar effect for NHL.
Source: Pipkin S, et al. AIDS 2011;25:463–471.
Link Between Protease Inhibitors and Poor Kidney Transplantation Outcomes
HIV-infected patients who undergo kidney transplantation with its associated immunosuppressive therapy to prevent rejection may require higher levels of immunosuppression or adjustment of antiretroviral therapy (ART) to a regimen that precludes protease inhibitors to reduce the risk of organ rejection. A recent prospective study by Stock and colleagues reported unexpectedly high rejection rates (31% and 41% at 1 and 3 years, respectively) following kidney transplantation in individuals with well-controlled HIV infection on ART (CD4+ T-cell counts >200/mm3 and undetectable plasma HIV RNA).
One factor contributing to increased rejection in the setting of HIV infection and ART may be a pharmacokinetic interaction between immunosuppressant drugs such as tacrolimus and protease inhibitors. In a letter to the New England Journal of Medicine commenting on the findings of Stock and colleagues, van Maarseveen and colleagues propose that because “the pharmacokinetic curve of tacrolimus in HIV patients receiving protease inhibitors does not show that normal peak-and-trough pattern but rather resembles a flat line with a half-life of up to 20 days as a result of extremely strong inhibition of CYP3A,” patients on an ART regiment that includes protease inhibitors require higher tacrolimus trough levels (17.5 ng/mL at 1 month and 10 ng/mL at 1 year posttransplant) than the levels reported in the study by Stock and colleagues (9.1 and 7.2 ng/mL at 1 month and 1 year posttransplant).
A comprehensive review of this important concern will appear in an upcoming issue of AIDS Patient Care and STDs.
Sources: Stock PC, et al. N Engl J Med 2010;363:2004–2014 and van Maarseveen EM, et al. N Engl J Med 2011;364:683.
Identification of Specific Behavior and Economic Changes Underlie HIV Decline in Zimbabwe
Over the 10-year period 1997–2007, HIV prevalence in Zimbabwe declined by nearly 50% (from a peak of 29% to 16% in 2007), a reduction unmatched in other sub-Saharan African nations. A study aimed at identifying the main factors contributing to this substantial decline points to changes in sexual behavior and, in particular, a reduction in multiple, concurrent sexual partners as the major cause of the decrease in HIV prevalence. Based on this finding, future prevention strategies targeting regions with generalized HIV epidemics might be expected to benefit from a greater emphasis on partner reduction, combined with traditional programs to promote condom use.
The authors of the study concluded that increased fear of contracting HIV and a greater awareness of the high AIDS mortality rate were the primary motivating factor underlying the behavior change in Zimbabwe. This fear likely led to less extramarital, commercial, and casual sex and fewer concurrent sexual relationships. A secondary driver was the economic decline in Zimbabwe that peaked during the late 1990s to 2000s. Less disposable income likely amplified the reduction in unsafe sexual practices such as paying for sex and having multiple sexual partners.
Source: Halperin DT, et al. PLoS Med 2011;8:e1000414.
Diagnosis of HIV Infection Highest Among African Americans
The Centers for Disease Control and Prevention (CDC) released statistics that illustrate a clear disparity in the rates of HIV diagnoses among African Americans in the United States compared to other racial/ethnic groups. For the period 2005–2008, black adults and adolescents accounted for nearly half (46.4%) of HIV diagnoses, even though they represent only 13.6% of the U.S. population. In contrast, whites comprised 67.9% of the population and accounted for 29.4% of the HIV diagnoses; Hispanics/Latinos accounted for 13.4% of the population and 17.8% of diagnoses.
Data collected from the National HIV Surveillance System for the year 2008 indicate that the estimated rates of HIV infection for black males and females was 8 and 19 times the rates for white males and females, and 2 and 4 times greater than for Hispanic/Latino males and females, respectively. Rates of HIV diagnosis among black males rose during the 2005–2008 study period, whereas the HIV rates for black females, whites, and Hispanics/Latinos remained relatively stable. HIV transmission among black males was most frequently associated with male-to-male sexual contact (61.1%), heterosexual contact (23.1%), and injection drug use (11.9%).
Source: MMWR 2011;60:93–98.
HIV Exposure In Utero and Vaccine-Related Antibody Responses
Antibody levels measured in a group of infants at birth in Cape Town, South Africa, revealed that infants that were exposed to HIV in utero but were not infected had significantly lower specific antibody responses to five vaccine-preventable diseases compared to unexposed infants. Specific antibody levels were measured for Haemophilus influenzae type b (Hib), pneumococcus, Bordatella pertussis antigens, tetanus toxoid, and hepatitis B surface antigen. Postvaccination serum samples collected from the infants at 16 weeks showed robust antibody responses for the HIV-exposed uninfected infants compared to the unexposed infants. In particular, the HIV-exposed uninfected infants had higher antibody responses to pertussis and pneumococcus. Among the mothers, the HIV-infected women had lower specific antibody levels to Hib and pneumococcus, with no differences in antibody levels to pertussis or tetanus between the HIV-infected and uninfected women.
Source: Jones CE, et al. JAMA 2011;305:576–584.
INFORMATION TECHNOLOGY
Internet is Important Source of Health Information
A survey conducted as part of the Pew Internet Project points to health information as one of the most common subjects internet users research online. The survey found that 80% of internet users (representing about 59% of adults in the United States) search for health information online. Only email and search engine use ranked higher among the online activities included in the survey.
The most common health information searches focused on a specific disease or medical condition, followed by information on treatments or procedures, doctors or other health professionals, hospitals or other medical facilities, health insurance, and environmental health hazards. Other popular search topics included drug safety or recalls, pregnancy and childbirth, memory loss, dementia, or Alzheimer's disease, medical test results, managing chronic pain, long-term care for the elderly or disabled, and end-of-life decisions.
Source: Pew Research Center's Internet & American Life Project.
HIV Information Accessed on the Internet
When a group of college students was asked where they would look for information if a friend or loved one acquired HIV/AIDS, the nearly universal response was to type “HIV and AIDS” into an Internet search engine. The resulting Google or Yahoo search yielded an overwhelming 24 million or so hits, according to the findings from investigators at North Carolina A&T State University–Greensboro. Few students took advantage of Google's “advanced search” option to refine the results, and the students did not appear concerned about whether the information they accessed came from an authoritative source. One of the hits resulting from the “HIV and AIDS” search was the Medical Library Association's website, which guides users to such reputable sources as the National Cancer Institute, CDC, American Academy of Family Physicians, and the U.S. Department of Health and Human Services.
Source: Charlotte Observer February 15, 2011.
TUBERCULOSIS
Optimal Tuberculosis Treatment in Children Requires Individualized Isoniazid Dosing
An in silico study in which 10,000 simulated pediatric patients with tuberculosis were treated with isoniazid ranging in dose from 2.5 to 40 mg/kg per day showed that none of the doses achieved the optimal 80% effective concentration (EC80) in ≥90% of cases. While recommended isoniazid doses in children range from 5 to 15 mg/kg per day, the study authors reported that doses of 5 mg/kg were universally inadequate, and doses of 10–15 mg/kg were only sufficient in children who had a slow acetylation phenotype and had TB pneumonia but not TB meningitis. The authors of the study concluded that currently recommended doses of isoniziad in children with TB are likely suboptimal. As the pharmacokinetics of isoniazid is variable in children younger than 10 years of age and the drug's ability to penetrate into phagocytic cells, epithelial lining fluid, and subarachnoid space in the setting of TB meningitis also varies, the authors suggest that dosing should be individualized and based on a child's age, disease process, and acetylation status.
Source: Antimicrob Agents Chemother 2011;55:539–545.
HEPATITIS C VIRUS
Declining Incidence of Acute HCV Over 25 Years
CDC investigators reported a substantial decrease in the average incidence of acute hepatitis C virus (HCV) infection between the periods 1982–1989 (7.4/100,000 individuals) and 1994–2006 (0.7/100,000). Acute hepatitis C infection typically presents with minimal symptoms and clinical cases represent only about 20–30% of all newly acquired cases. Liver damage ensues as chronic infection develops. The CDC estimates that 3.2 million Americans have chronic hepatitis C and about half are not aware they are infected.
This study of incidence and transmission patterns of acute HCV in the U.S. from 1982 to 2006 found that the most common risk factor for acquiring HCV throughout the 25-year study period was injection drug use (IDU). The proportion of cases linked to IDU increased from 31% during 1982–1989 to 45.6% during 1994–2006. In contrast, transmission of HCV via blood transfusion has shown a steady decline since screening of the donated blood supply for HCV began in 1992. The CDC estimates that the risk of HCV transmission through the blood supply is now about 1 in 2 million.
Source: Arch Intern Med 2011;171:242–248.
HUMAN PAPILLOMA VIRUS
HPV Links Oral Sex and Cancer Risk
Adolescents may think that oral sex is less risky than intercourse and has no health consequences, but presenters at the recent American Association for the Advancement of Science's (AAAS) annual meeting suggested otherwise. They discussed the role human papilloma viruses (HPVs) may have played in the 225% increase in oral cancer cases in the United States between 1974 and 2007. In fact, HPV is challenging tobacco use as the main cause of oral cancer.
HPV infection is the primary cause of more than 90% of all cervical cancers, and HPV vaccination is recommended for teenage girls to protect against infection. The presenters discussed the potential for using an HPV vaccine of young males to prevent HPV transmission resulting from oral sex. There is not, however, sufficient data to identify the primary HPVs involved in the development of oral cancer.
Source: CDC HIV/Hepatitis/STD/TB Prevention News Update.