Sexual Health Roundup: Promising Advances in HIV Prevention and Treatment; New Evidence on HPV, Cancer, and Vaccines


Scientists Engineer Stem Cells to Target HIV

A new study published in the journal PLoS Pathogens finds that engineered stem cells can effectively target and suppress HIV in living tissue. Scientists from the University of California, Los Angeles engineered human blood stem cells and implanted them in  “humanized mice.” HIV infection in these mice closely resembles the disease in humans so this gave them a good platform to study the effects on a living being.

The scientists then tested the mice’s blood, plasma, and tissue two weeks and six weeks after implantation of the cells. They found “that the number of CD4 ‘helper’ T cells—which become depleted as a result of HIV infection—increased, while levels of HIV in the blood decreased. CD4 cells are white blood cells that are an important component of the immune system, helping to fight off infections.” Based on these results, they concluded that engineered cell can develop and migrate to organs and fight infection there.

As one of the researchers explained: “We believe that this study lays the groundwork for the potential use of this type of an approach in combating HIV infection in infected individuals, in hopes of eradicating the virus from the body.”

The researchers cautioned, however, that some differences between the immune system of the mice and those of humans might mean different results in people.

A Pill That Can Prevent HIV Gets Tested in California, But is it Worth the Money?

Truvada is a combination of two drugs used to treat HIV (tenofovir-emtricatabine) that has been shown in a clinical trial to reduce an individual’s risk of HIV infection by an average of 44 percent (up to 73 percent in some) if taken daily. The pill is very expensive, however, at $26 per pill or $10,000 a year per person.

In a new study, researchers at Stanford University used an economic model to analyze the cost effectiveness of this new prevention method.  They focused on men who have sex with men (MSM) because according to the CDC 56,000 new HIV infections occur in this group each year. They concluded that giving the pill to all MSM would cost $495 billion dollars over 20 years and that if 20 percent of all MSM took the pill daily there would 63,000 fewer infections over those 20 years. Giving the pill just to those MSM considered high-risk (those who have five or more partners in a year) would cost only $85 billion dollars over 20 years and if 20 percent of this group took the pill daily it would result in 41,000 fewer infections over those 20 years.

They concluded, therefore, that it was more cost effective to target just those MSM who are at highest risks for becoming infected with HIV.

California may be the first state to test this theory. The state announced last week that it will conduct a trial of the HIV-prevention pill with 700 high-risk HIV-negative gay and bisexual men and transgender women in Los Angeles, San Diego, and Long Beach.

The trial is part of an $11.8 million state program that is also working to get 3,000 HIV-infected people in Southern California into treatment. The grants have been awarded to different campuses of the University of California as well as local governments and AIDS organizations.

Some experts are optimistic about this new prevention method but others are skeptical that individuals will take their pills daily. Moreover, some fear that the pill will be viewed as another reason not to use condoms and as such may increase HIV infection and the spread of other STDs.

Given the limited resources available to HIV/AIDS- prevention and treatment efforts, it also seems fair to question providing such an expensive intervention that requires daily action by individuals when behavior changes such as having fewer partners and using a condom every time can prevent HIV for significantly less money.

New HPV-Cancer Numbers Underscore the Need to Vaccinate Boys Too

The CDC released new data showing that HPV causes 18,000 cancers in women and 8,000 in men each year. Researchers analyzed data in two large cancer registries collected between 2004 and 2008. Though by now most people know that HPV is the cause of almost all cervical cancer, they may not know that it causes many other cancers as well.  HPV is responsible for one third of all penile cancers, two thirds of all mouth and throat cancers, and 93 percent of anal cancers.

Among women, cancers caused by HPV are more common than ovarian cancer and nearly as common as melanoma skin cancers. In men, cancers caused by HPV are as common as invasive brain cancer.

And yet, somehow we are still fighting an ideological battle over the available HPV vaccines, Gardasil and Cervarix. Though these vaccines have for years been recommended by the CDC for girls, in 2010 less than a third of all girls had received all three doses necessary for the vaccines to be effective. The vaccines were not recommended for boys until last year and there are not yet numbers available on how many young men have been vaccinated.

I’ve said it before and I’ll say it again now—we have a vaccine against cancer. It prevents cancer! Parents need to stop listening to the voices that say it causes promiscuity and run (not walk) to their pediatrician’s office as soon as their kids are old enough.  I know I will.

South Carolina Takes Steps to Encourage HPV Vaccinations

It’s clear that we need to take steps to expand HPV vaccinations for young people but given how politicalized the issue has become, widespread state efforts are likely to be controversial. We all remember the political heat Texas Governor Rick Perry took for his decision to mandate HPV vaccines for school girls in his state. Still, a House panel in South Carolina has a plan to encourage parents to get their middle school children vaccinated.

Last week, the House’s Medical, Military, and Municipal Affairs Committee approved a bill requiring the state’s Department of Health and Environmental Control (DHEC) to provide educational brochures about HPV to parents of all students entering the seventh grade. The brochures will encourage parents to get the vaccine but will not require it.

The bill, which is set to go to the full House, faces some obstacles. While it is estimated that it will cost DHEC nearly $312,000 to produce the brochures and provide additional vaccines to those who come to public health clinics, the department is only required to do this if lawmakers approve the bill and provide the money.

Though no group has vocally opposed the idea yet, a 2007 bill on this topic became very controversial. That bill, which required middle school girls to be vaccinated, was opposed by the South Carolina Baptist Association as well other groups and was defeated unanimously.

Still, the sponsor of the current bill is optimistic about its chances because it recommends the vaccine but does not mandate it.  

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