Abstract
Genetic Finding Regarding Transmission Between Male Partners
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By using a method of comparing genetic characteristics (phylogenetic analysis), the researchers studied a group of men who had sexually transmitted HIV to other men. By analyzing the viral sequences extracted from the blood and semen of HIV-transmitting partners, the researchers were able to estimate the dates of origin and the source of the rapidly mutating HIV. The team found that recipients shared a more recent common ancestor with virus from the seminal plasma than with virus found in the seminal cells of their source partner. Most HIV infections result from exposure to the HIV virus in semen, made up of seminal cells and seminal plasma. HIV particles contain RNA and exist in the plasma, whereas infected seminal cells contain HIV DNA.
Now that it has been determined that HIV RNA is transmitted during sex, new prevention strategies can be developed that focus on HIV in the seminal plasma. These may include vaccines, vaginal microbicides, and antiviral drugs. Although the study was based on pairs of men, the findings may be translated to women. HIV RNA in seminal plasma is also likely to be the reason behind sexual transmission of HIV from men to women. However, additional studies will be necessary to confirm this in women.
The study was published in the February 10 issue of Science Translational Medicine, 2010;2(18):18re1.
HIV/TB Coinfections Hitting Hispanics Hard
A significant ethnic shift is occurring in the cases of HIV/tuberculosis (TB) co-infections in the United States. Specifically, the majority of new cases now come from the Hispanic community, particularly in the San Diego area.
Overall, the number of cases remains modest in the Southern California city. Originally, coinfection with HIV and TB was most often seen in white and black patients. The findings of a new study now suggest that it is a problem largely among Hispanics.
Researchers from the University of California San Diego analyzed San Diego County TB surveillance data from 1993 through 2007. Each case of TB was grouped into one of three categories based on HIV status: positive, negative, or unknown. In total, 5,172 TB cases were analyzed. Of these, 8.8% were deemed coinfections of TB and HIV. Although the number of new coinfected cases did not change significantly during this period, the proportion of cases among Hispanics increased significantly. At the same time, the proportion of cases among non-Hispanic white and black patients decreased.
According to public health officials, Hispanics now account for more than 80% of all TB–HIV coinfection cases in the county. They are likely to be 30 to 49 years old and injection drug users. In addition, they were born in Mexico. Mexicans regularly cross the border. The researchers believe that efforts to prevent TB–HIV coinfection must be bi-national in nature.
More details about the study can be found in the February 10 online ahead of print edition of the American Journal of Public Health.
Behavioral Factors Influence HPV
Various behavioral characteristics of parents—not medical history or background—determine whether they are willing to have a daughter vaccinated against human papilloma virus (HPV). Researchers at Fox Chase Cancer Center in Philadelphia have found that some surprising factors influence the decision. One of these is cigarette smoking.
Behavioral factors linked to whether parents would vaccinate their daughters include physical activity, nonuse of complementary or alternative therapies, and cigarette smoking. The smoking factor was surprising, in that risky behaviors are associated with a lower likelihood of adopting harm-prevention strategies. In the case of vaccinating against HPV, the researchers postulate that smokers have a greater awareness of cancer and, therefore, are more apt to have their daughters get the vaccine.
The researchers used information from the 2007 Health Information National Trends Survey conducted by the National Cancer Institute. From this, they analyzed cross-sectional survey data from more than 1,300 U.S. parents or guardians of female children or adolescents younger than 18 years. The study found that approximately 18% of the parents would not have their daughter receive the HPV vaccine. Another 25% were undecided about it. However, more than half (about 58%) reported they would let their daughter receive the vaccine.
Parents who were reluctant to have their daughters vaccinated cited various reasons for saying no. The most common reason, given by 48%, was that they simply did not know enough about the vaccine. About 20% were worried about the safety of the vaccine. Some of the parents (about 9%) said they believed their daughter was not sexually active. About 6% cited not receiving a recommendation from a doctor for their daughter to receive the vaccine. Other reasons that were cited were the daughter being young, the belief that more research on the HPV vaccine is needed, a parental antivaccination philosophy in general, and the belief that their daughter simply did not need the vaccine.
Current or former smokers were more accepting about having their daughters get the vaccine. Another positive factor was having engaged in health-promoting behaviors such as physical activity within the past month. Those parents who had not used alternative/complementary therapies within the past year were also likely to accept vaccination. The belief that cancer can be cured if caught early also was associated with vaccine acceptance.
The findings from this study were published in the February issue of Cancer Epidemiology, Biomarkers & Prevention, 2010;19(2):319–326.
New Vaccine Against TB Shows Promise
Results from clinical trials conducted in Tanzania show that a new vaccine against tuberculosis (TB), Mycobacterium vaccae (MV), is effective in preventing tuberculosis in people with HIV infection. The vaccine is a type known as an inactivated whole-cell mycobacterial vaccine. Developing a vaccine against TB remains a significant international health priority.
Researchers at Dartmouth Medical School started phase I human studies with MV in the United States in 1994. At that time, they demonstrated that a multiple-dose series of MV was safe in both healthy subjects and patients with HIV infection. Phase II studies were next conducted in larger groups of patients in Zambia and in Finland. In the Zambian trial, the researchers found that MV boosted immune responses against TB. Subsequently, a large phase III efficacy trial began in Tanzania, called the DarDar Health Study.
The study found that MV immunization reduced the rate of definite tuberculosis by 39% among 2,000 HIV-infected patients in Tanzania. Because newly infected HIV patients risk contracting TB almost immediately, the researchers are targeting a strategy for administration of MV before patients need to start taking antiretroviral drugs.
More work must be done to improve the manufacturing methods required to support the production of larger vaccine quantities. This is needed to conduct further studies and to use the vaccine in a clinical setting. Currently, such development work on the manufacturing side is being conducted by the Aeras Global TB Vaccine Foundation in Rockville, Maryland, in conjunction with the London-based manufacturer, Immodulon Therapeutics. It is expected that the vaccine will be economical to produce and distribute.
The study was published online ahead of print in the January 28 edition of AIDS.
Premature Aging Observed in HIV Patient Brains
New research is discovering that individuals with HIV infection undergo premature aging changes in their brains. Specifically, blood flow to these brains resembles the same patterns as those found in uninfected people who are 15 to 20 years older. At present, researchers at Washington University in St. Louis do not know whether HIV itself, antiretroviral medications, or both are contributing to the findings.
A growing number of individuals with HIV are becoming older. An estimated 14 to 18% of all HIV-infected persons in the United States are older than 50 years. In addition, older people face one of the highest rates of new infections. By 2015, people older than 50 years are expected to account for more than half of all individuals infected with HIV.
For their study, researchers used MRI scans to study the blood flow in the brains of 26 HIV-infected and 25 noninfected individuals. Age and education levels were similar in both groups. They found reduced blood flow in the brains of younger HIV-infected patients who were infected recently, not just the older ones.
More details on the study can be found in the February 1 issue of the Journal of Infectious Diseases, 2010;201(3):336–340.
Male Abusers Often Sabotage Birth-Control Efforts
Male partners of teenage girls and young women who engage in physical and sexual violence often try to sabotage any birth control the women are using. As a result, these women are twice as likely to experience an unintended pregnancy. The finding comes from recent research conducted by investigators at the University of California at Davis School of Medicine.
During 2008 through 2009, about 1,300 women aged 16 to 29 years took part in the study by responding to a computerized survey. All had sought care at five reproductive health clinics in Northern California.
The researchers found that approximately 15% of the women said they had experienced birth-control sabotage. More than half of those surveyed reported physical or sexual violence from a partner. Of the women who had experienced partner violence, more than one third also acknowledged experiencing either pregnancy coercion or birth-control sabotage. According to the researchers, reproductive coercion may explain why abused women and teens have more unintended pregnancies.
The study was published in the January 29 online ahead of print edition of Contraception.