YESTERDAY, MAY 18, was celebrated as HIV Vaccine Awareness Day.
Persons around the world showed their support for HIV vaccine research by wearing the symbol of the disease, the AIDS ribbon, upside down to create a 'V' for 'vaccine' and the vision of an AIDS-free world. This is the eighth year of commemoration, and the theme was 'Hope for the future'.
Researchers and community support organisations used the day to highlight the challenges and successes associated with both the disease and vaccine research, to acknowledge the contribution made by vaccine participants, and to recognise the need for a broader based community education and action.
COMPLEX PROCESS
The day illustrated forcefully the reasons why HIV vaccines offer an important means for controlling the AIDS pandemic in the future. However, developing an effective vaccine is complex and the variability of the virus is challenging.
Vaccine trials involve scientists and volunteers from around the world. The biggest collaboration undertaken so far is by the HIV Vaccine Trials Network (HVTN) established in 1999 in Seattle, Washington State. Vaccine trials are conducted in the USA, Latin America, Asia, the Caribbean and Southern Africa.
HIV vaccinology is similar to that used to combat other pandemics of the past. The research process starts with ideas about the most effective chemicals to combat the disease in question, followed by tests on animals. Unless these tests suggest that the product is safe, it is not given to humans.
There are three stages of clinical testing in humans that an HIV experimental vaccine goes through, before it can be considered by the Food and Drug Administration (FDA) for licensure or use in public health.
This type of research is called clinical trials and is divided into three phases as follows:
Phase one usually requires anywhere between 20 and 80 healthy volunteers (HIV negative) and at low risk for HIV infection. This type of research looks at data on the safety and various doses of the experimental vaccine collected on volunteers over a period of 12-18 months.
Phase two involves several hundred volunteers (HIV negative) at both high and low risk for HIV infection, information on safety and immune response is
collected and may last as long as two years.
Phase three involves thousands of volunteers (HIV negative) at high risk for HIV infection. At this phase of clinical trial, scientists look at the effectiveness of the
experimental vaccine, which may last as long as four or five years.
SPECIAL TECHNIQUES
Up to late 2004, some 40 vaccines had been tested in phases one and two, and only one phase three trial had been completed. HIV experimental vaccines cannot cause HIV infection or AIDS since they are not made from live HIV, killed HIV, weakened HIV or HIV infected blood.
Instead, scientists use specially assembled techniques to reassemble parts of the HIV that are not virulent to develop vaccines, with the hope of stimulating an immune system response.
Vaccine development is long and painstaking. A preventive vaccine can, therefore, be long in the making.
There are other challenges to HIV/AIDS and HIV preventive vaccines. HIV/AIDS is a highly charged issue, primarily because it is associated with issues of social exclusion such as poverty, marginalisation and sexual habits.
All research on HIV vaccines is regulated by the Ethics Committees (EC) or Institutional Regulatory Body (IRB) of the country or state in which the research is conducted; the sponsor agency and the FDA.
Governmental approval is sought before a clinical trial is conducted. These regulatory bodies have the responsibility to ensure that clinical research conforms to the highest ethical standards and that the welfare of volunteers is not neglected.
For more information visit the Website: www. hvtn.org
