A preventive vaccine against the human immunodeficiency virus (HIV), the virus that causes AIDS, is a top priority for human health, and our best hope for a world without AIDS.
AIDS is still here
About 35 million people worldwide are now infected with HIV. Since the start of the epidemic, over 70 million people have become infected with HIV, and over 35 million people have died of AIDS. World-wide, AIDS has become the leading infectious disease cause of death, and the sixth leading cause of death overall.
There is no human example of someone clearing an HIV infection naturally. Fortunately, treatment known as antiretroviral therapy now exists. But in low- and middle-income countries, only around 10 million people living with HIV have access to treatment. This is about 34% of people who are eligible for treatment.
Vaccines have significantly reduced or eliminated a number of deadly infectious diseases.
Preventive vaccines have been used for decades around the world. When manufactured and used properly, they are very safe, and it is more cost-effective to prevent diseases than to treat them.
Vaccines get the credit for eliminating smallpox worldwide. Soon the same will be true of polio. More recently, a vaccine against a cancer-causing virus, human papilloma virus (HPV), was approved. We hope one day to be able to add an HIV vaccine to the list of diseases preventable by a vaccine.
What about other approaches?
- While treatment for HIV infection and AIDS has dramatically improved, it is no substitute for prevention. Current HIV medications are very expensive, and they have many side effects.
- Sometimes people develop drug resistance and have to change the regimen of pills they take.
- Access to these drugs is not guaranteed, and some middle- and low-income countries do not have access to the same medicines that are available in the US and Europe.
- The rate of new infections around the world is greater than our ability to get treatment to the people who need it.
These days, there is also the option of using the drug Truvada to prevent HIV infection (known as pre-exposure prophylaxis, or PrEP), and so it’s tempting to think an HIV vaccine is no longer necessary. PrEP is an important new addition to the existing methods of HIV prevention, but it is unlikely to be an option for everyone -- the pills are expensive, may cause side effects, and may not be accessible to everyone. 
Another prevention option researchers are studying is called antibody mediated prevention (AMP). If successful, this method can also provide protection. However, it will likely require regular injections or infusions, and may not appeal to everyone who needs protection. In addition, cost may be a factor, as with other prevention methods.
Vaccines remain the most efficient and effective way to eliminate an infectious disease. They are an effective, affordable and practical option.
Science has come a long way since HIV was discovered.
HIV was identified in 1983. In comparing the time spent on preventive HIV vaccine research to other vaccine development timelines, the fact that we are still looking for a vaccine is not surprising; it took 47 years to develop the polio vaccine!
There is no licensed vaccine against HIV or AIDS, but we are getting closer than ever before. In 2009, a large-scale vaccine study conducted in Thailand showed that a 2-vaccine combination could reduce new infections by nearly one third.
Finding a safe and effective HIV vaccine that will protect people around the world is a formidable but necessary task. HIV is a powerful opponent, but scientists are constantly learning from one another and using advanced technology to fight it. Scientific understanding continues to improve all the time. The HVTN is leading the effort to build on what we’ve learned so far, and planning for several large studies is underway.