What is in the future for HIV Vaccine?
Early advances in preventing HIV transmission resulted from educational programs describing how transmission occurs and providing barrier protection for those exposed to genital secretions and new needles or bleach to those exposed to blood by sharing needles. Despite these efforts, new infection in both the developed and developing worlds has continued at high rates.
Historically, the greatest success in preventing viral transmission has resulted from the development of preventative vaccines. Unfortunately, decades of research to develop an HIV vaccine has led to little hope for success. While the vaccine which has been developed demonstrated only limited evidence of protection, research is under way to further explore what can be learned for future vaccine development from this modest success.
In light of the limited ability of counseling and testing to curb the spread of the HIV pandemic, many researchers have moved toward other biologic strategies for preventing HIV. During the last 10 years, there were several studies showing that male circumcision along with behavioral counseling reduced the risk of heterosexual men acquiring HIV infection. This provides a prevention strategy for at-risk, HIV-uninfected heterosexual men. Since the summer of 2010, there have been several other promising advances in the field of HIV prevention. This included the CAPRISA 004 study which showed that vaginal administration before and after intercourse of a gel containing the antiretroviral agent tenofovir reduced the risk of transmission of both HIV and herpes simplex virus to heterosexual women. Finally, in the fall of 2010 the iPrEx study reported the results of the first large study testing the effectiveness of pre-exposure prophylaxis, so called “PrEP.” In this study, HIV-uninfected men who had sex with men who took tenofovir DF/emtricitabine (TDF/FTC, Truvada) once daily along with a comprehensive program to promote safe sex practices and early treatment of sexually transmitted diseases, experienced a markedly reduced risk of acquiring HIV compared with those receiving similar prevention practice without TDF/FTC. There are several other studies under way testing the safety and effectiveness of PrEP in other at-risk groups such as heterosexuals and intravenous drug users. These data are very new, and the use of antiretrovirals for PrEP is not yet approved or considered the standard of care. A great deal of discussion will ensue over the coming months between government agencies, academia, industry, and the community to determine how PrEP should move forward.
A final prevention strategy of last resort is the use of antiretrovirals as post-exposure prophylaxis, so called “PEP” to prevent infection after a potential exposure to HIV-containing blood or genital secretions. Current guidelines suggest that those experiencing a needle stick or are sexually exposed to genital secretions of an HIV-infected person should take antiretrovirals for four weeks. Those individuals considering this type of preventative treatment, however, must be aware that post-exposure treatment cannot be relied upon to prevent HIV infection. Moreover, such treatment is not always available at the time it is most needed and is probably best restricted to unusual and unexpected exposures, such as a broken condom during intercourse. If PEP is to be initiated, it should occur within hours of exposure and certainly within the first several days. Updated guidelines that help prevent the spread of HIV, you should:
- Use a new condom every time you have sex. If you don’t know the HIV status of your partner, use a new condom every time you have anal or vaginal sex. Women can use a female condom. Use only water-based lubricants. Oil-based lubricants can weaken condoms and cause them to break. During oral sex use a condom, dental dam( a piece of medical-grade latex) or plastic wrap.
- Use a clean needle. If you use a needle to inject drugs, make sure it’s sterile and don’t share it. Take advantage of needle-exchange programs in your community and consider seeking help for your drug use.
- Tell your sexual partners if you have HIV. It’s important to tell anyone with whom you’ve had sex that you’re HIV-positive. Your partners need to be tested and to receive medical care if they have the virus. They also need to know their HIV status so that they don’t infect others.
- If you’re pregnant, get medical care right away. If you’re HIV-positive, you may pass the infection to your baby. But if you receive treatment during pregnancy, you can cut your baby’s risk by as much as two-thirds.