The AIDS Pandemic

Dr. David Wessner

In this podcast, students of Davidson College and I will explore the biology of HIV/AIDS, its history, and review the latest scientific advances related to this pandemic.

  1. 10/26/2010

    What does HIV/AIDS cost? The answer to this question depends a lot on whom you ask.

    Ask the UN and you’ll get the staggering sum of $10 billion. A year . The annual per capita cost of treating infected Africans, where much of the UN money goes, is around $1,100. One of the major problems facing HIV/AIDS advocates is their inability to lower this number. An estimated $600 is spent on anti-retroviral drugs, while the remaining $500 is spent on other AIDS associated conditions. Even $10 billion wouldn’t cover treatment for the more than 20 million Africans with HIV/AIDS. A considerable portion of the proposed UN budget is directed not towards treatment but towards prevention. A major problem is that no one can seem to agree on the actual cost. Although the UN has held firm to their estimate, other groups have presented vastly different figures. The World Health Organization has presented four different scenarios which vary wildly in both the projected outcome and cost. To merely maintain the current status quo, WHO estimates more than $400 billion will need to be spent over the next 20 years. To significantly reduce annual new HIV infections, WHO’s figure is more than $700 billion. Unfortunately such different figures can sometimes complicate funding by making it hard for donors to decide how much to give. Ask someone who is living with HIV/AIDS and you’ll get a number that’s a lot smaller. The average AIDS patient in America takes a combination of drugs that add up to around $14,000 a year . Much of this cost in the US is defrayed by private insurance, government insurance or sometimes through AIDS drug assistance programs (ADAPs) . These programs are meant to provide access to drugs for low income individuals. Currently 89% of people enrolled in ADAPs make less than 300% of the federal poverty level. However recently the economic conditions have forced many states to scale back their support of these programs. States have either closed enrollment entirely, or narrowed eligibility-forcing people to drop out. Currently the nationwide waiting list is at an all time high of 3,586 people . Ask the companies that manufacture these lifesaving drugs and you’ll be back to huge figures. One of the newest drugs to enter the market, Fuzeon , is produced by the giant Swiss company, Roche. Roche maintains that Fuzeon’s price (nearly $20,000 a year, or three times the next most expensive drug) is due to the $600 million cost of development. The average drug begins to turn a profit in 16 years, but analysts estimate that Fuzeon’s pricing, and anticipated demand, could mean profits for Roche in as little as three years. Ask an economist and you’ll get a couple different figures. By 1995 more than $75 billion had been spent on AIDS. Since then, spending has increased most years, with an average of $10 billion more being spent every year. But money spent directly on AIDS does not even begin to cover the true cost. In addition, economists have tried to measure the costs related to lost productivity, wages, and premature death, due to the disease. Figures vary, but some think that indirect costs account for nearly 80 percent of the total cost of AIDS. Worst case scenario guesses estimate that AIDS robs the world of 1.4% of gross domestic product, or the equivalent of wiping out the economy of Australia . A government study in Uganda found that some companies are hiring and training two employees for a single job in the hope that one will stay healthy. The UN estimates that since 1981 AIDS has reduced Africa’s overall labor force by 25%. Sick days and absenteeism due to AIDS related illness have further reduced productivity in the countries hit hardest by AIDS. Ultimately the cost of HIV/AIDS is extraordinarily difficult to measure. The disease affects so many people worldwide that it would be impossible to assess the impact that it has had on everyone. However it is obvious that unless something drastic changes, the costs will continue to grow until they become unbearable.

  2. 10/19/2010

    A Picture of Life with HIV in Africa

    Africa. The seed of the world. One of the most beautiful and most scintillating places on earth. From the deserts of the Sahara and the rainforests of the Congo to the bright and bustling metropolis of Cape Town, life is rich everywhere. Yet amidst all this beauty and splendor, a deadly scourge threatens the people of this continent. AIDS. Sub-Saharan Africa is more heavily affected by HIV/AIDS than is any other region in the world. Somewhere around 22.4 million people in the region are currently living with HIV. This makes up a whopping two-thirds of the global number of HIV-infected individuals. Whereas in other areas of the world the disease affects only certain groups, here, HIV/AIDS affects everyone. This affliction picks apart whole extended families one by one. Schools are gradually emptied over time as students are orphaned. Healthcare and economic development have all taken a hard hit because of the impact of HIV/AIDS on the African peoples. Organizations simply don’t have the funds to support or expand prevention, treatment and care efforts and for this reason, it is likely that the death count will continue to rise. Life expectancy has been drastically reduced across the continent, falling to as low as 31 years in some of the worst afflicted areas. HIV/AIDS is present everywhere we look. It is an unavoidable aspect of everyday life. The following dialogue includes excerpts from various interviews. I spoke with a group of college students who lived for six months in South Africa and Zambia, another student who lived 2 years in Nigeria, and a field biologist currently doing research in Cameroon. Their testimonies will enhance the picture of daily life in African countries afflicted with HIV/AIDS. Take the country of Cameroon, for example. As of 2008, the population in Cameroon neared 19 million. Of that, about 600,000 are living with HIV/AIDS. More than half of that is made up of women 15 years and older. While prevalence here is much lower than other countries, HIV/AIDS remains a chief concern. When asked about general knowledge about the disease, most agreed that the “information is very available to middle and upper class citizens, but not necessarily to the lower class citizens and those that are at highest risk.” There is a large focus on prevention here, and the country is littered with billboards promoting abstinence, safer sex practices and condom use. Public Service Announcement in Cameroon “Sex can wait…my future comes first.” South Africa is a key example of a country, of a government that has failed its people. Until very recently, the government took no part in the fight against AIDS. Thabo Mbeki, president from 1999 to 2008 refused to believe that HIV causes AIDS and that condoms can prevent infection. This leadership has fueled outlandish beliefs such as that condoms cause AIDS, or that white people are pushing condoms laced with AIDS to wipe out Africans. When asked about the role of the government in the fight against AIDS, one student said, “The president is not very influential considering he stated that he took a shower after having had sex with someone infected with AIDS, and therefore he would not contract the disease.” Here, she is referring to the current president, Jacob Zuma, who publicly stated that showering after sex with an HIV-positive woman would reduce his risk of being infected. A fellow student added, “NGOs are much more active. They have done a much better job fighting AIDS through their provision of important information and items such as condoms and antiretrovirals.” Incumbent President of South Africa, Jacob Zuma The picture of life here has changed drastically since AIDS exploded on the scene. While treatment and prevention are improving in some areas, the governments of more conservative countries, such as South Africa, need to step up and face this issue with full force so that HIV/AIDS is no longer a shadow looming over the lives of everyone. Facts and figures were obtained from AVERT International HIV and AIDS charity, the Global Health Council, USAID, and Elizabeth Pisani’s The Wisdom of Whores. I would like to recognize Albert Noah-Messomo, an African native of the Beti people in the rainforest of Cameroon. His traditional African-style music was featured during this Podcast. I would like to thank Kurt Kristensen, Sara Levintow, Nikki Pagano, and Rebecca McQuade for their contributions to this Podcast.

  3. 10/14/2010

    Compulsory HIV Testing

    No one can argue that HIV testing is a bad thing. Knowing one’s status allows a person to access treatment earlier, change risky behaviors, or rest assured that he/she is indeed HIV negative. With that said, why not make HIV testing mandatory for everyone? Hello, I am Katie Morris and this is The AIDS Pandemic, a podcast hosted by Dr. Dave Wessner, associate professor of biology, and his students at Davidson College. Compulsory HIV testing—which requires that the entire population, or at least certain high-risk groups, is tested for HIV—has gotten a bad reputation in recent years from human rights activists who argue for a person’s right to choose to know whether or not they have HIV. However, studies have shown that usually, once a person knows he/she is HIV positive he/she will change his/her risky behaviors to avoid transmitting it to anyone else. Would compulsory testing not at least hinder the spread of HIV among populations? I fully support the freedom of choice, however I also support the right to live and if compulsory testing can reduce the number of people dying from AIDS it should at least be considered by policy makers around the globe. One of the largest barriers to HIV research and prevention programs in the developing world is a lack of knowledge of the specific epidemics in each country. By requiring people to be tested for HIV, the public health community would gain valuable information on how many people are infected and what groups are most at risk, significantly aiding prevention programs. Bill Clinton, the former President of the United States and founder of the Clinton foundation, which funds a great number of HIV/AIDS programs around the world, is an advocate for mandatory testing in developing countries with high HIV prevalence rates. In a statement made to Reuters, he said, "[W]e can save people's lives, and we can reduce the stigma. There is no way we are going to reduce the spread of this epidemic without more testing because 90% of the people who are HIV-positive don't know it." Everyone who is sexually active, injecting drugs, receiving blood transfusions, or breastfeeding is at risk for contracting HIV, regardless of their age, skin color, education, financial status, or sexuality. Therefore in order to increase more individuals’ knowledge of their statuses so that they do not unknowingly spread HIV, testing needs to go beyond voluntary clinics. In the aforementioned quote, President Clinton made a statement about reducing the stigma around HIV by implementing mandatory testing. This statement is contrary to what many human rights groups argue. Their concern is primarily with confidentiality breaches, especially in the developing world where the poor infrastructure cannot guarantee secure record keeping and adequate training for counselors. While a valid concern, so much of stigma surrounding HIV in the developing world involves testing itself. People are reluctant to be tested because they associate HIV testing with people who are promiscuous, homosexual, or drug users. By requiring everyone to be tested, the stigma associated with those walking into an HIV testing clinic is eliminated. Also, in places like sub-Saharan Africa where many countries have HIV prevalence rates above 5%, mandatory testing has the possibility to normalize being HIV positive. Of course this requires time and the decision by people to be open about their status but there is potential to show that everyone and anyone can contract HIV and that good things—like treatment, support groups, and advocacy opportunities—can result from knowing your status earlier. Unfortunately, once you get into the implications of such a policy, things do not remain so straightforward. In the developed world, many argue that compulsory testing is simply a waste of money. That same Reuters report found that in order for population-wide mandatory testing to be cost-effective, the prevalence rate should be above 5%. In the United States where HIV prevalence is believed to be less than 0.004%, mandatory HIV testing may not be the most financially wise decision even though the U.S. is one of the few countries that can actually afford to successfully implement a compulsory HIV testing program. It should be noted that there are certain high-risk groups in specific regions of the U.S. with prevalence rates above 5% that could benefit from mandatory testing. However, requiring testing of one group and not another can be considered discrimination and stigmatize or alienate certain people. In the developing world where, again, many countries, particularly in sub-Saharan Africa, have HIV prevalence rates above 5% and could seemingly benefit from population-wide HIV testing, new issues arise. First and foremost, these countries lack the resources to be able to test everyone. HIV tests are expensive and require sanitary facilities, laboratories, and trained professionals to draw blood. With this blood test, it can take up to three months to obtain results, creating a large loss due to follow-up. Furthermore, what happens next? HIV testing is only beneficial if it is accompanied by proper education and counseling. These are additional costs and require more trained professionals that are difficult to find in the developing world. If a person tests positive, where do they go from there? Will policies be enacted that require the person to disclose their status to their friends, family, or sexual partners? How will this be enforced? What if ART is not available or affordable to the person who tests positive? Their positive test results have just come as a death sentence, which can lead to a fatalistic attitude and discourage behavior change. If a person tests negative, there is a danger of developing a complacent attitude—since he/she does not have the virus, he/she may feel no responsibility to the HIV epidemic. Although the benefits to compulsory HIV testing are clear, the realities of implementing a population wide mandatory testing campaign around the world make it not the best option at this point in time. In the developed world where prevalence rates are low, the cost of HIV tests outweigh the benefits of finding the few positive people. This might not always be the case in the future with treatment regimens improving and the early-detection of HIV reducing the long-term opt-out costs of ART. In the developing world, infrastructure, financial, and human resource barriers raise concerns to human rights groups and make the implementation of such a program a nightmare. Also, there remains the question of what to do from a policy standpoint for the people who do test positive. Compromises can be made to reap some of the benefits of compulsory testing without requiring all of the necessary resources. First, there are certain groups that should be required to have HIV tests—pregnant mothers to prevent transmission of HIV to their babies, health professionals to reduce the risk to patients, and sex workers in areas like the Netherlands where their profession is regulated. Second, opt-out HIV testing policies (administering an HIV test to everyone except those who specifically ask not to be tested) are a great way to encourage more HIV testing without requiring it. This is more effective in the developed world where people go for annual health check-ups but there are creative ways to bring opt-out to the developing world through mobile clinics strategically placed in markets, farms, churches, or schools. Compulsory HIV testing is a messy topic but that doesn’t mean the discussion should end there. We should continue to find ways to have as many people as possible aware of their HIV status in hopes of slowing the spread of the HIV epidemic. Katie Morris, & David R. Wessner (2010). Compulsory HIV Testing The AIDS Pandemic

  4. 07/07/2010

    Born HIV Free campaign to end mother-to-child-transmission

    “By 2015, let us end the transmission of HIV from mother to child. This is not a dream: we can do it.” Carla Bruni-Sarkozy, The Global Fund Ambassador With that simple statement from Ms. Bruni-Sarkozy as its guiding principle, the Global Fund to Fight AIDS, Tuberculosis, and Malaria has launched Born HIV Free. The goal of this new initiative is straightforward – stop the mother-to-child transmission of HIV. As Ms. Bruni-Sarkozy notes, this goal is achievable. We have at our disposal the means of protecting our children from infection. When an HIV+ woman becomes pregnant and gives birth, the virus can be transmitted to the infant during gestation, during delivery, or through subsequent breast-feeding. These types of transmission collectively are referred to as mother-to-child transmission. The terms vertical transmission and perinatal transmission also may be used. We now know that relatively simple and relatively cheat antiviral regimens can dramatically reduce the rate of mother-to-child transmission. In a 1999 study, Dr. Mary Lou Lindegren and colleagues noted that rates of perinatal transmission dropped significantly in concert with zidovudine (AZT) treatment for the mothers. With the development of better drug regimens, these drops in transmission rates have continued. According to the CDC, an estimated 1,650 HIV-infected infants were born in the US in 1991. In 2004, that number had dropped to less than 200. This success, however, has not been mirrored in developing countries. The causes of this disparity are several-fold. The most important factors affecting the continued problem of mother-to-child transmission of HIV in developing countries include access to treatment and access to testing. In recent years, antiretroviral drugs have become more available throughout the developing world, thanks, in large part, to the influx of money from sources such as the United States PEPFAR program and the United Nation’s Global Fund. Additionally, other groups, most notably the Clinton Foundation, have fought hard to make these drugs more affordable. But we need to do more. Too many HIV+ women still do not have access to the necessary treatments. In addition to making drugs more available, we also must work diligently to increase the levels of testing. Treatment to prevent perinatal transmission requires that women know their HIV status. To find out more about the Born HIV Free campaign, please visit their website at http://www.bornhivfree.org. Let’s join Ms. Bruni-Sarkozy in ending the transmission of HIV from mother to child.

  5. 11/20/2009

    Taking Lessons from the CCR5Δ32 Mutation for Patient Treatment

    I’m Lindsay Sween, and welcome to this installment of the AIDS Pandemic blog and podcast. Human immunodeficiency virus type 1 (HIV-1) invades a CD4+ (T4) cell through the attachment of the viral protein gp120 to its primary cellular receptor, CD4, and to a transmembrane chemokine coreceptor, usually CCR5 or CXCR4. Agrawal et al. (2007) explain that the removal of 32 base pairs from the CCR5 gene results in the CCR5Δ32 mutation, which produces a shortened, nonfunctional protein that cannot act as a coreceptor due to the fact that it is no longer expressed on the cell membrane. Thus, individuals homozygous for the CCR5 mutation (also known as CCR5 -/- individuals) are extremely resistant to contracting HIV-1, while heterozygous people (aka CCR5+/- people) express fewer CCR5 proteins on the surface of their lymphocytes than wild type individuals, which slows the transition of HIV infection to AIDS. The CCR5Δ32 mutation confers HIV-1 resistance by two mechanisms: the mutated protein cannot be expressed on the lymphocyte surface, and it actively downregulates CXCR4 coreceptor production by causing the formation of heterodimers between CCR5 and CXCR4 proteins that then get trapped in the endoplasmic reticulum. As explained by Nazari and Joshi (2008), individuals with the CCR5Δ32 mutation appear perfectly healthy in all other areas of their immune systems, which seems to indicate that the CCR5 chemokine receptor is not absolutely essential for immune function. Thus, with no selective pressure against the CCR5Δ32 mutation, Agrawal et al. (2007) report that Caucasians carry the mutation relatively frequently, with about 1% of individuals being homozygous for the mutated allele and approximately 10% of the population being heterozygous. Individuals of purely African or Asian descent, however, almost entirely lack the CCR5Δ32 mutation. Figure 1. The CCR5Δ32 mutation results in a nonfunctional protein that cannot serve as a cell surface coreceptor for M-tropic (aka CCR5-tropic or R5) HIV viral isolates and, thus, confers some resistance to HIV-1 infection. The immune cells are still fully receptive to T-tropic (aka CXCR4-tropic or X4) viral isolates, which could bind to their coreceptor, CXCR4 (aka fusin), and transmit HIV-1 infection. From: Samson, Michel. “Human immunodeficiency virus (HIV).” Access Science Online. McGraw-Hill. . There is now a new antiretroviral drug called maraviroc, which was approved by the U.S. Food and Drug Administration U.S. Food and Drug Administration in August 2007 and mimics the natural CCR5Δ32 mutation by acting as an antagonist for the CCR5 receptor and preventing the viral envelope protein gp120 from binding to it. Lieberman-Blum et al. (2008) report the results of two Phase IIb/III clinical trials, MOTIVATE 1 and 2, in which the effects of treatment with 300 mg of maraviroc once or twice daily were compared to placebo treatment in patients who were already being treated with HAART and still had primarily R5 HIV-1 infection. Maraviroc was found to decrease viral load by a greater percentage than placebo. Of the patients receiving maraviroc once or twice daily, 43.2% and 45.5%, respectively, had virus particle counts of less than 50 copies per milliliter, as opposed to 16.7% of patients in the placebo group. After the 48 weeks of the studies, patients demonstrated average viral load reductions of -1.68 log10 copies/mL for the once daily group and -1.84 log10 copies/mL for the twice daily group compared to -0.78 log10 copies/mL for the control group. Figure 2. Most patients given maraviroc once or twice daily had lower HIV-1 viral loads and higher CD4 cell counts at the end of 48 weeks and had a long time period until treatment failure than did patients taking placebo. From: Gulick, R.M., Lalezari, J., Goodrich, J., Clumeck, N., DeJesus, E., Horban, A., Nadler, J., Clotet, B., Karlsson, A., Wohlfeiler, M., Montana, J.B., McHale, M., Sullivan, J., Ridgway, C., Felstead, S., Dunne, M.W., van der Ryst, E., Mayer, H. 2008. Maraviroc for Previously Treated Patients with R5 HIV-1 Infection. The New England Journal of Medicine 359: 1429-1441. As would be predicted by the absence of adverse health problems in individuals lacking functional CCR5 receptors due to the CCR5Δ32 mutation, maraviroc produced few severe side effects for the immune system by blocking the CCR5 surface protein. According to Lieberman-Blum et al. (2008), 21 of 426 (4.9%) individuals taking maraviroc and 11 of 209 (5.3%) individuals taking placebo had poor health outcomes that lead them to stop taking their medication and quit the trials. Most patients (92.3%) reported at least one side effect, which included upper respiratory illness, cough, fever, and abdominal pain. The primary concern with the use of antiretroviral drugs that block the CCR5 receptor is that the HIV virus will evolve into X4 or R5X4 variants that will then evade the drug’s action. For the individuals who were not benefitted by maraviroc, 54.4% of the once-daily patients and 55.2% of the twice-daily patients demonstrated virus that had changed from the R5 strains to either X4 or R5X4 strains. When the researchers performed phylogenetic analyses of the viral envelope proteins in these strains, however, they found that the new X4 or R5X4 strains had developed from preexisting viral particles of these strains that had been missed in the screening process before the beginning of the drug trials and had not resulted from R5 mutation during the course of drug treatment. Thus, these clinical trials suggest that maraviroc could be a good possibility for “salvage therapy” for those HIV+ individuals who have experienced treatment failures in the current categories of HIV/AIDS medications. More studies are still needed, however, to determine the long-term effects of antagonizing the CCR5 receptor. The CCR5Δ32 genetic mutation and the recent research investigating it and its therapeutic implications are very relevant topics given the fact that the HIV/AIDS pandemic is one of the greatest public health concerns in the world, especially in developing nations. As cited in Lieberman-Blum et al. (2008), the Joint United Nations Programme on HIV/AIDS and the World Heath Organization report that as of 2007 33.2 million people worldwide were HIV+, and 2.5 million of those cases were new infections. In addition, the virus’s high mutation rate makes viral resistance to current antiretroviral medications a growing problem for disease treatment. The research into the CCR5Δ32 mutation aided scientists in developing the new class of antiretroviral drugs known as CCR5 antagonists. Furthermore, most new infections of HIV-1 are caused by R5 (also known as CCR5-tropic or macrophage-tropic) viral isolates. Thus, gene therapy involving the complete downregulation of CCR5 by the CCR5Δ32 mutation inserted into cells via viral vectors could one day prevent transmission of HIV by removing the coreceptor in the semen-receiving individual. Through the CCR5Δ32 mutation, evolution and natural selection may have unwittingly supplied we humans with a very powerful weapon in the fight against the HIV/AIDS pandemic. For more information, please see: Agrawal, L., Jin, Q., Altenburg, J., Meyer, L., Tubiana, R., Theodorou, I., Alkhatib, G. 2007. CCR5Δ32 Protein Expression and Stability Are Critical for Resistance to Human Immunodeficiency Virus Type 1 In Vivo. Journal of Virology 81: 8041-8049. Lieberman-Blum, S.S., Fung, H.B., Bandres, J.C. 2008. Maraviroc: A CCR5-Receptor Antagonist for the Treatment of HIV-1 Infection. Clinical Therapeutics 30: 1228-1250. Nazari, R., Joshi, S. 2008. CCR5 as Target for HIV-1 Gene Therapy. Current Gene Therapy 8: 264-272.

  6. 11/11/2009

    The Search for an HIV vaccine

    I'm Paige Bates and this is The AIDS Pandemic The RV144 study was a phase III HIV vaccine trial conducted by the US Army and Thai government over seven years on 16,402 volunteers—all HIV negative men and women between the ages of 18 and 30 in parts of Thailand. For ethical reasons, all participants were taught HIV prevention behaviors, given condoms, and promised lifelong antiretroviral treatment if they contracted HIV. Half of the volunteers were given a prime-boost vaccine regimen and half received placebo vaccinations. The prime-boost approach utilizes Sanofi Pasteur’s ALVAC-HIV vaccine as a prime and AIDSVAX (originally made by Genentech) as a boost. ALVAC-HIV is comprised of a canarypox virus with three HIV genes grafted onto it. AIDSVAX contains a recombinant gp120 protein found on the surface of HIV. These vaccinations were combined because one was designed to create antibodies and the other to alert white blood cells. These vaccinations were focused on the two strains of HIV commonly found in Thailand, but it is unclear whether this regimen would have any benefit elsewhere in the world. The participants were regularly tested for HIV for three years following the completion of the vaccine regimen. In September, the companies and agencies which implemented and funded the trial announced in a press release and interviews that new HIV infections were observed in 74 of the 8,198 people who received the placebo, but in only 51 of the 8,187 given the vaccine. They claimed that this was a statistically significant 31.2% reduction in infection. However, the vaccine did not reduce levels of HIV activity in those who became infected and did not appear to produce any neutralizing antibodies. Source: Wall Street Journal, September 25, 2009 In the 1980s, top officials embarrassed themselves by predicting an HIV vaccine in five years. Reminiscent of these overly optimistic declarations, the backers of the RV144 trial claimed that “we now have evidence that a safe and effective HIV vaccine is possible.” In the first wave of press subsequent to the initial press release and interviews, many reputable news sources, such as the San Francisco Chronicle, New York Times, NPR radio and BBC news, suggested that these results were highly encouraging, and some even went so far as to suggest that this regimen might be the forerunner or basis for a usable vaccine in the near future. The LA Times suggested that these findings would “energize and redirect” the HIV vaccine field. Many articles quoted Dr. Anthony S. Fauci, the director of the National Institute of Allergy and Infectious Disease which largely funded the $100 million dollar study, as saying “I don’t want to use a word like breakthrough, but I don’t think that there’s any doubt that this is a very important result.” The Wall Street Journal suggested that this finding could be the second “big game changer in AIDS research since the mid 1990’s” with the advent of drug cocktails. Many articles later qualified with the cautionary statement that much more research is necessary before the vaccine could be available to the public. Phrases urging the public to be “cautious” but “hopeful” and describing the results as “modest” yet “encouraging” rang throughout the media and press releases. However, only days later, the LA Times wrote “By Thursday afternoon, the initial wave of euphoria had given way to the recognition that many vexing questions will have to be answered before researchers can produce a vaccine that will reliably shield people from HIV.” Experts predicted that it would require two to three years of research to unravel how and why the vaccine regimen worked, and then an additional five to ten years to produce a vaccine that was ready to test in people. The fact that this still overly optimistic statement was a step back from the “initial euphoria” shows the extent of the preliminary sensationalism. The media reported that the researchers would now compare the blood of those who were vaccinated and resisted infection, and those who did not in order to determine whether the regimen stimulated antibodies or other protective molecules against HIV infection. In an article entitled “If AIDS went the way of smallpox,” a New York Times reporter recognized many problems with the initial reports including that many headlines in the first 24 hours after the press release read “One Third Protected,” while in reality the margin of success was “razor thin.” In addition, even the experts overseeing the trial could not explain why blending two failed vaccines suddenly resulted in “working” vaccine. Finally, this article recognized the financial difficulties surrounding a regimen that requires six shots over the span of months resulting in minimal protection. While this might be practical in rich countries, AIDS generally burdens the poorest nations in this world. Only one article mentioned that some researchers were suggesting that the apparent reduction in infections might be a statistical fluke due to the small number of HIV infections observed. Throughout all articles, there were minimal reminders to keep vigilance about prevention, testing, and the necessity to utilize current retroviral care. Source: Wall Street Journal, October 12, 2009 In 2004, there was so much skepticism about this trial that 22 top AIDS researchers published an editorial in Science magazine suggesting it was a waste of money. Five years later, the organizations which conducted the trial announced in a press release that there has been significant protection, before making the scientific data available to peer review. When the full details of the study were released on October 20th at a meeting in Paris, the statistic frailty of the study was revealed. The vaccine was not shown to protect people at the highest risk of HIV infection. As The Washington Post noted on October 21st, when the results are analyzed using alternate methods, the protection is no longer statistically significant. For example, when only the people who received all six injections are counted, the trend towards protection is no longer significant. This raises many questions. What are the societal implications of the press surrounding this vaccine? If this vaccine doesn’t have much, if any, effect, what is the societal consequence of the data being overstated? The possibility of a public backlash against vaccination efforts wouldn’t be too hard to imagine. In fact, Gregg Gonsalves, an AIDS activist, remarked that, “When this was rolled out a couple of weeks ago, it was terribly hyped by the investigators. Some people think that you have to dangle the slimmest morsels of hope in front of the general public in order to keep them interested in an AIDS vaccine. But I think that damages the credibility of the effort.” The extent to which these results might represent a breakthrough can only be determined after the mechanism behind the possible conferred immunity is discovered. As Gonsalves points out, the over-exaggeration of the success in the media will likely hurt the results of the study if they prove to be less remarkable than originally stated. Furthermore, this study raises a general question about scientific results: is it appropriate to have news press releases before data is available for full review by scientific peers? While this trial may not have been the scientific breakthrough that it was praised as, at the very least, this tremendous study is an example of international and interagency collaboration in conducting a large-scale vaccine trial, including the Thai and US governments, private companies such as Sanofi Pasteur, and non-profit organizations such as Global Solutions for Infectious Diseases (GSID). In this regard, it provides incredible hope for HIV vaccine efforts in the future. For more information, please see these articles. US Military Research Program in Thailand BBC news coverage of RV144 The Wall Street Journal: Data Call ito Question HIV Study Results

  7. 10/17/2009

    Intersecting Epidemics: HIV/AIDS and Tuberculosis

    Hi, I’m Justin Eusebio. While tuberculosis is one of the world’s oldest surviving plagues and HIV-1 infection is one of medicine’s newest challenges, there is an undeniable relationship between HIV/AIDS and tuberculosis. Independently, Mycobacteria tuberculosis and HIV are formidable pathogens but in concert, the prospects for controlling either epidemic are jeopardized. TB-HIV coinfection and interaction complicate all aspects of each disease: pathogenesis, epidemiology, clinical presentation, diagnosis, treatment, prevention, and even social and economic issues. Not only are individuals more likely to undergo tuberculosis infection if living with HIV, depending on their geographic location, people living with HIV infection are 6-50 times more likely to develop active TB than people living without HIV. Thus, with one-third of the world’s population at least latently infected with Mycobacteria tuberculosis, the current pace of new HIV-1 infections threatens public health on a wide scale. Tuberculosis infection is believed to have the greatest potential among other common opportunistic infections to increase viral load and to accelerate HIV-1 disease progression. This is in part due to the chronic nature of active TB disease, the marked increase in tumor necrosis factor-alpha (TNF-α) expression for macrophage activation, and intensified antigen presentation causing the recruitment of CD4 T lymphocytes to the site of TB infection. Manoff and others demonstrated that active tuberculosis is associated with increased viral load in HIV-1 infected patients. Also, TB-HIV coinfected persons have a significantly higher HIV RNA load than persons without opportunistic infections and similar CD4 cell counts. Figure 1. Schematic hypothetical individual’s of risk of TB infection compared to CD4 cell count. From: Havlir, Diane V., Haileyesus Getahun, and Ian Sanne. “Opportunities and Challenges for HIV Care in Overlapping HIV and TB Epidemics.” Journal of the American Medical Association 300.4 (2008): 423-430. Researchers from Case Western Reserve University demonstrated that not only do TB-HIV co-infected patients have significantly higher viral loads than those without TB, the timing of infection by M. tuberculosis affects HIV-1 disease progression. In fact, these researchers showed that TB had its strongest impact on HIV-1 viral load when patients are least immunodeficient. Furthermore, from the same study, more than 25% of TB-HIV coinfected patients developed TB when their CD4 cell counts were at least 500 cells/µl. Thus TB infection is unique because it can occur at any CD4 cell count level. Perhaps the most problematic tuberculosis-induced effect contributing to HIV-1 disease progression is its apparent impact on HIV-1 evolution. While reverse transcriptase, a polymerase without proofreading capabilities, provides an effective mechanism for genetic diversity, M. tuberculosis infection increases HIV-1 heterogeneity through compartmentalization. In a cohort of patients matched by their CD4 cell counts, dually infected TB-HIV patients were found to have greater systemic, or more general, HIV-1 heterogeneity and more frequent occurrences of distinct HIV-1 quasispecies than HIV-1 patients without TB infection. A population of diverse quasispecies increases the viral capacity to evolve and adapt to the host immunological response. Furthermore, upon examination of the lung sites of M. tuberculosis infection of TB-HIV coinfected patients, Collins and others found greater genetic HIV-1 heterogeneity and distinct quasispecies in the pleural space compared to blood samples. While phylogenetically distinct HIV-1 subpopulations have been shown to develop in other organs or tracts in humans (i.e. kidneys, brain, urogenital tract and blood), compartmentalization of HIV-1 occurs most significantly and is more defined in the lungs of co-infected TB-HIV patients. Therefore, the lungs, induced by active tuberculosis disease, function as a reservoir for genetically diverse HIV-1. In addition to accelerating the disease progression of one another, their collision has highlighted underlying public health and human rights failures. Africa, although only home to 10% of the world’s population, is the major site of intersection between the two epidemics with an astounding 75% of the world’s TB-HIV coinfections. Figure 2. The disproportionate incidence of HIV and HIV-TB coinfection in Africa in 2000. Each person indicates 5% of the global population. The African population is shaded red while blue represents the rest of the world. From: Corbett, Elizabeth L, Barbara Marston, Gavin J. Churchyard, and Keven M. De C**k. “Tuberculosis in Sub-Saharan Africa: Opportunities, Challenges, and Change in the Era of Antiretroviral Treatment.” Lancet 367 (2006): 926-937. Thus, novel TB diagnostic tests are needed in HIV-endemic regions because HIV infection reduces the sensitivity of current diagnostic methods such as direct smear sputum microscopy. In terms of treatment, high pill burden and toxicity often discourage adherence among many coinfected patients. Furthermore, rifampicin, a common antibiotic component of tuberculosis chemotherapy disrupts antiretroviral treatment by accelerating the metabolism of both protease inhibitors and nonnucleoside reverse transcriptase inhibitors (NNRTs). Finally, if antiretroviral treatment of coinfected patients is started too soon after treatment for TB, a rapid recovery of CD4 T cell levels may induce an overwhelming inflammatory response against previously hidden opportunistic infections resulting immune reconstitution inflammatory syndrome (IRIS). The connection between the biology of the two diseases is clear and complications are numerous. Thus, experts in HIV and experts in TB should respond accordingly and move towards greater collaboration and shared research. Until next, this is Justin Eusebio. For more information: Bartlett, John G. “Tuberculosis and HIV Infection: Partners in Human Tragedy.” Journal of Infectious Diseases 196 (2007): S124-5. Collins, Kalonji R., Miguel E. Quioñones-Mateu, Mianda Wu, Henry Luzze, John L. Johnson, Christina Hirsch, Zahra Toossi, and Eric J. Arts. “Human Immunodeficiency Virus Type 1 (HIV-1) Quasispecies at the Sites of Mycobacterium tuberculosis Infection Contribute to Systemic HIV-1 Heterogeneity.” Journal of Virology 76.4 (2002): 1697-1706. Collins, Kalonji R., Miguel E. Quioñones-Mateu, Zhara Toossi, and Eric J. Arts. “Impact of Tuberculosis on HIV-1 Replication, Diversity and Disease Progression.” AIDS Review 4 (2002): 165-176. Kalonji Collins et. al, “Greater diversity of HIV-1 quasispecies in HIV-infected individuals with active tuberculosis.” Journal of Acquired Immune Deficiency Syndrome 24, 408-417. Friedland, Gerald, Gavin J. Churchyard, and Edward Nardell. “Tuberculosis and HIV Coinfection: Current State of Knowledge and Research Priorities.” Journal of Infectious Diseases 196 (2007): S1-3. Manoff, SB, H Farzadegan, A Muñoz, JA Astemborski, D Vlahov, RT Rizzo, L Solomon, and NM Graham. “The Effect of Latent Mycobacterium tuberculosis infection on Human Immunodeficiency Virus (HIV) Disease Progression and HIV RNA Load Among Injecting Drug Users.” The Journal of Infectious Diseases 174.2 (1996): 299-308. Nunn, Paul, Alasdair Reid, Kevin De C**k. “Tuberculosis and HIV Infection: The Global Setting.” The Journal of Infectious Diseases 196 (2007): S5-14. Vignuzzi, Marco, Jeffrey K. Stone, Jamie J. Arnold, Craig E. Cameron, and Raul Andino. “Quasispecies Diversity Determines Pathogenesis through Cooperative Interactions within a Viral Population.” Nature 439.7074 (2006): 344-348.

  8. 10/02/2009

    Preventing Mother to Child Transmission of HIV in Mwandi, Zambia- A Success

    Welcome to this installment of the AIDS Pandemic, a podcast hosted by Dave Wessner of the Department of Biology at Davidson College. I am Sarah Bertram. This past summer, I traveled to Mwandi, Zambia through a Davidson biology and pre-medical program. Mwandi is a predominantly Lozi village of about 7,000 people and the catchment area totals about 25,000 people. We spent 5 weeks in Africa, 3 of which were spent working in the Mwandi Mission Hospital, the Mwandi AIDS clinic, the Orphans and Vulnerable Children’s center, and the Mother and Child Health Center. We all went with a research topic to study that was based on some aspect of Mwandian life. I looked at Mwandi’s Prevention of Mother to Child Transmission of HIV, otherwise known as the PMTCT program, and its effectiveness over the past three years. Here, I will talk about my findings. About out of every five pregnant women in Zambia is infected with HIV and without any prevention or treatment interventions, more than 300,000 babies would contract HIV from their mothers each year. Starting in 1999, many Zambian mission and government hospitals started PMTCT programs. The Mwandi PMTCT program was launched in 2005 by an American Pediatrician in conjunction with the Mwandi missionary who was going to serve as the leader of the program. The procedure for PMTCT at the Mwandi Mission Hospital is as follows: 1) discuss the PMTCT program and HIV/AIDS information during group antenatal care visits, 2) offer private pre-test counseling, 3) test the mother for HIV and CD4 counts and give her the results, and 4) offer post-test counseling and discuss further treatment and a re-test in three months. According to the hospital staff in Mwandi, HIV testing of any pregnant mother is required by law in Zambia. If a woman tests positive, she is evaluated at the Pastoral Care Center for AIDS treatment. If she is considered a WHO stage IV or has multiple symptoms for WHO stage III, HAART treatment is usually started unless the woman chooses to undergo short-course treatment instead. Many of the HIV positive mothers choose to undergo HAART treatment because of its documented increased ability to treat HIV/AIDS symptoms and to lower the viral load by decreasing viral replication. The Mwandi hospital staff is good about giving options to the positive mothers and explaining each option and its risks and benefits. Due to the staff’s willingness to counsel and inform the HIV positive pregnant mothers of treatment options, a majority of these women decide to take part in a course of HIV/AIDS treatment in order to help themselves and to prevent the transmission of HIV to their babies. Although record-keeping is sparse and sometimes hard to find and evaluate, some records for the PMTCT program proved helpful in evaluating the program’s success over the years. From March of 2005 to September of 2007 (before HIV testing was mandatory), 1,205 women attended an antenatal care appointment to sign up for the PMTCT program and of these 1,205 women, only 35 women or about 3% refused the HIV test. Of the 1,170 women who agreed to be tested, 24.4% tested positive for HIV. This statistic is quite high, but reflects the belief that about 1/3 to ¼ of Mwandi’s population is infected with HIV. Because the PMTCT program was in place, the HIV positive women were able to learn their status, get treatment, and prevent (for the most part) the transmission of HIV to their babies during pregnancy, delivery, and breastfeeding. Mwandi’s PMTCT program has changed drug regimens in order to stay current with the most effective treatments. Originally, the program was based on a single dose of nevirapine given to the mother during delivery and to the baby right after birth. In April of 2006, the PMTCT program switched to a dual therapy involving both nevirapine and AZT for both mothers and babies. Starting in November of 2007, Mwandi updated its treatment regimen to the most current and effective triple therapy drug treatment. This drug therapy involves a mixture of AZT, 3TC, and NVP for the mother and baby. This new therapy has proven to be very effective and the PMTCT program workers approximate that transmission from mother-to-child rates have decreased to less than 10% and possibly even as low as 6% or 7%. Possibly the most enticing aspect of the PMTCT program for pregnant women is the free formula feeding program provided to HIV-negative babies of HIV-positive mothers. Breastfeeding is the most common type of mother-to-child HIV transmission, so by providing free formula for those babies who test negative (after 6 weeks of age), the worry of transmission by breastfeeding can be alleviated. Currently there are over 100 babies receiving infant formula and most, but not all, are HIV-negative babies of HIV-positive mothers who participated in the PMTCT program. The program has never resulted in a case of child dysentery, a common negative outcome of formula feeding programs, which is often a result of incorrectly boiled water used to make the formula. This clean record is a result of the care and attention put forth into teaching the mothers how to correctly make the formula and clean the bottles. Compared to many other Sub-Saharan African PMTCT programs, Mwandi’s program is doing a very good job of keeping the program advancing, as far as the number of women being treated and the updates to newer forms of drug therapies. The program could however still make larger strides in incorporating more women from far out in the catchment area and by possibly providing more rural village outreaches for the sole purpose of PMTCT.

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About

In this podcast, students of Davidson College and I will explore the biology of HIV/AIDS, its history, and review the latest scientific advances related to this pandemic.

Information

  • Creator
    Dr. David Wessner
  • Years Active
    2006 - 2010
  • Episodes
    19
  • Rating
    Explicit
  • Copyright
    © Copyright 2007
  • Show Website
    The AIDS Pandemic