Among heterosexuals in the United Kingdom (UK), HIV transmission can occur
within networks of as many as 30 people, according to a new study by
researchers at the University of Edinburgh, Scotland, and the Medical
Research Council Clinical Trials Unit, London. Details are published
September
25 in the open-access journal PLoS Pathogens.

The number of HIV-infected heterosexuals in the UK has been growing
dramatically and now exceeds the number of HIV-infected homosexual men.
Most are
immigrants from sub-Saharan Africa, a group for which the pattern of virus
transmission is poorly documented.

To better understand the dynamics of the heterosexual HIV epidemic within
the UK, the research group, led by Professor Andrew Leigh Brown, applied
the
novel technique of phylodynamics, which reconstructs the pattern of viral
sequence divergence in time in order to reveal the size of transmission
clusters and the dynamics of transmission within them.

The team studied virus gene sequences from over 11,000 infected
individuals, comprising 40% of the HIV-infected heterosexual population in
the UK,
making this one of the largest studies of its kind to date. By analyzing
differences between the viral strains, they found clusters of related
viruses
that showed 5% of HIV transmissions to have occurred in networks of more
than 10 people

The authors note the importance to their work of the UK HIV Drug
Resistance Database, which contains viral DNA sequence information from
over 30,000
infected individuals. Using this database, the researchers discovered that
transmission clusters in the heterosexual population were smaller than
those found among HIV-infected homosexual men and that transmission was
also much slower. The study concludes that heterosexual transmission could
be
significantly reduced by early diagnosis and treatment.

“The slower dynamics of the heterosexual epidemic thus offer more
opportunity for successful intervention, but it is essential that
diagnosis is
achieved as early as possible,” said Professor Leigh Brown.

Financial Disclosure: This work was supported by the Medical Research
Council. The UK HIV Drug Resistance Database is partly funded by the
Department
of Health; the views expressed in the publication are those of the authors
and not necessarily those of the Department of Health. Additional support
was provided by Boehringer Ingelheim, Bristol-Myers Squibb, Gilead,
Tibotec (a division of Janssen-Cilag Ltd) and Roche. The funders had no
role in
study design, data collection and analysis, decision to publish, or
preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests
exist.

Citation:
“Molecular Phylodynamics of the Heterosexual HIV Epidemic in the United Kingdom.”
Hughes GJ, Fearnhill E, Dunn D, Lycett SJ, Rambaut A, et al. (2009)
PLoS Pathog 5(9): e1000590. doi:10.1371/journal.ppat.1000590

Source
PLoS Pathogens

Brazil’s nearly two-decade effort to treat people living with HIV and AIDS shows that developing countries can successfully combat the epidemic. Inexpensive generic medicines are a large part of the solution, say researchers from Brown University and the Harvard School of Public Health.

Brazil did this, researchers said, largely by pursuing controversial policies that prompted pharmaceutical companies with exclusive drugs to lower their prices dramatically and generic companies to develop lower-cost alternatives for use in emerging markets.

“Brazil has proved it is possible to treat people with AIDS in developing countries,” said lead author Amy Nunn, assistant professor of medicine (research) at The Warren Alpert Medical School of Brown University. She added that the country saved more than $1 billion as a result of bargaining with multinational pharmaceutical companies, resulting in significant changes in global AIDS policy.

That effort, Nunn said, has had a wide impact.

“Before Brazil’s efforts, as recently as the year 2000,” she said, “most people living with HIV/AIDS in developing countries died without receiving treatment.”

Details of their findings will be published in the July/August issue of Health Affairs. Francisco Bastos, a well-known AIDS epidemiologist at the Oswaldo Cruz Foundation in Rio de Janiero, and Elize da Fonseca at the University of Edinburgh in Scotland also participated in the research. Senior author Sofia Gruskin is an associate professor of health and human rights at the Harvard School of Public Health in Boston, where the initial research began.

One of the biggest advances in Brazil’s push to address the advance of HIV and AIDS came in the 1990s, when the country passed a law guaranteeing free, universal access to drugs for AIDS treatment. The country also began producing generic AIDS medicines in public factories. Brazilian authorities also pressured drug companies to reduce their prices drastically for patented medicines by threatening to produce generic versions of those drugs.

Brazil was working to contain the virus years before taking that step. Researchers noted that Brazil began its HIV education and prevention campaigns early in the 1980s, focusing on condom distribution and HIV testing. Health officials also targeted prevention campaigns to those vulnerable to contracting HIV, including sex workers, injecting drug users and men who have sex with men.

The results were enormously beneficial. Researchers said the country¹s treatment initiatives also helped minimize the spread of the virus in Brazil. In doing so, health officials proved AIDS treatment was possible in a developing country. The example helped prompt sweeping changes in global public health policy and foreign aid relating to global health, with Brazil¹s actions as an example of how to make HIV/AIDS policies more effective.

Gruskin said that Brazil also spearheaded important changes in global health, trade policies, and international human rights protections related to medicines, and the country forced greater transparency about global drug prices.

An example of the change: Since 2003, the United States and other developed countries once opposed to Brazil¹s policies have invested billions of dollars annually to provide generic AIDS medicines to people in developing countries.

At home, Brazil kept its HIV/AIDS epidemic confined to .5 percent of the population. Today, about 660,000 Brazilians live with the disease.

Nunn said the study’s findings show that developing countries around the world can dramatically reduce AIDS-related deaths by treating patients. She added that the research highlights the value of strategic global political engagement by developing countries.

Still, there are challenges ahead. The study shows that the cost of treating HIV/AIDS patients in Brazil has risen in recent years. The long-term costs of treating people living with HIV/AIDS will continue to rise in other countries as more people receive treatment, life expectancy is extended, and patients require more costly and often patented medicines.

A number of organizations funded the research: The U.S. Departments of State and Education, the National Institute on Drug Abuse and the National Institute of Allergy and infectious Diseases.

Source:
Mark Hollmer
Brown University