A Vaccine for HIV

Overview

As of 2010, there is no recommended vaccine to prevent human immunodeficiency virus 1 (HIV) infection, and many challenges remain for developing a vaccine. HIV is the infectious organism, which leads to acquired immune deficiency syndrome (AIDS); the virus is transmitted most frequently by sexual intercourse. According to UNAIDS, there were approximately 2 million AIDS-related deaths and 2.7 new HIV infections acquired in 2008. HIV was identified as the viral cause of AIDS in the 1980s, and as of 2010, an estimated 20 million AIDS-related deaths have occurred and 60 million people have been infected with HIV.

HIV Infection

HIV infection causes a lifelong infection, which, if untreated, leads to AIDS within 10 years for most individuals infected with the virus. The virus can infect virtually all white blood cell types, but causes dramatic reductions in the numbers of helper T cells. HIV infection is chronic, and while highly active antiretroviral treatments (HAART) are successful in prolonging life, the treatment regimen is daily and offers no cure for the infection.

Preventative Measures

Condom use is an effective preventative intervention against sexual transmission of the disease. According to AVERT, the virus is also transmitted by injection drug users, but clean needle exchange programs are highly effective for preventing infection in this group. But for many diseases, vaccines have proven to be one of the most effective disease prevention tools, which, according to WHO Director General Margaret Chan, prevent an estimated 2 to 3 million deaths each year. Hope remains that an effective HIV vaccine will be developed.

Viral Challenge to Vaccine Development

Development of an effective HIV vaccine has been slow and difficult for a number of reasons. One of these reasons is that the virus frequently changes its genetic markers, making it difficult to know which marker to target to effectively prevent disease. In addition, even if the “correct” marker is able to be targeted by a vaccine, the virus can, and likely will, continue to change its genetic makeup, and be able to escape from vaccine-induced immune responses.

Recent Vaccine Trial

It is important to consider what an HIV vaccine could reasonably achieve. A vaccine that prevents 100 percent HIV infections at the site of infection would be ideal. Developing a 100 percent vaccine has been a real challenge to date, and currently it appears unlikely that a vaccine could prevent 100 percent of new HIV infections. Vaccine trials conducted in Thailand by Rerks-Nagam, et al. in 2009 recruited over 16,000 individuals and showed a 31 percent reduced risk of trial participants becoming HIV positive. Considering alternative tools and vaccine goals to prevent the spread of infection and slow disease progression to AIDS are also important.

Priorities

HIV/AIDS is a high priority global public health disease, which is targeted for reduction in the Millennium Development Goals (MDGs). There are a number of HIV/AIDS vaccine initiatives spearheaded by organizations including the International AIDS Vaccine Initiative (IAVI) and the HIV Vaccine Trials Network (HVTN).

About this Author

Onome Akpogheneta has been writing on health issues for more than a decade. Her work has appeared in the “Journal of Infectious Diseases.” Currently, she is the global pandemics correspondent at “The Faster Times.” Akpogheneta has a Doctor of Philosophy in malaria immunology with epidemiology. She graduated from the London School of Hygiene and Tropical Medicine in 2007.