At last, progress in developing an AIDS vaccine
Professor Alan Whiteside is an AIDS researcher and author. He is Professor of Economics and Director of the Health Economics and HIV/AIDS Research Division at the University of KwaZulu-Natal, South Africa, and is a member of the Governing Council of the International AIDS Society. He has written several books on HIV and AIDS, including HIV/AIDS: A Very Short Introduction. In this original post below, Professor Whiteside discusses the recent encouraging results of HIV vaccine trials in Thailand.
The human immunodeficiency virus the cause of AIDS, is fortunately not easily transmitted. When it first appeared in 1981, there were fears of a global epidemic, some thought it would be on the scale of the impending Swine flu (H1N1) outbreak. This has not and will not happened. However those who are infected will eventually develop AIDS and in the absence of treatment will die.
There are an estimated 33 million people living with HIV in the world. The majority are in sub-Saharan Africa and more women than men infected. Most HIV transmission takes place through unprotected sexual intercourse. Some people are infected through drug abuse – sharing contaminated needles. If a woman is HIV positive and pregnant then there is a chance that her child will be born with the virus or infected while breast feeding (vertical transmission).
HIV transmission can be prevented. In injecting drug using populations provision of clean needles will halt the epidemic – as was done in a number of western cities. It is rare for vertical transmission to occur in the rich world, pregnant women will be given drugs and babies formula feed, in the poor world one dose of nevirapine will greatly reduce risk. New interventions are being developed and tried and it is likely that this form of transmission can be further reduced.
Preventing sexual transmission requires behavior change. Clearly not being sexually active will ensure a person remains HIV negative. This is not an option for humankind or most individuals. Having only one partner (who is faithful) will be effective but again, human nature being what it is, this is not a realistic goal despite what many faith-based organizations would have us believe. Condoms are generally effective provided they are used consistently and correctly. Unfortunately this too is not always an option. In some settings they are not available or are discouraged by religious leaders. Women may not be empowered to insist or even ask their partners to use them. And of course there are many who just don’t like them.
I believe that halting the HIV epidemic requires a mix of behaviour change and science. With regard to behaviour the key is developing respect. People should not enter sexual relations without respecting each other. If they do then they will either be faithful or they will want to protect their partner(s) by knowing their HIV status and/or using condoms.
Science has brought us drugs that keep people alive albeit at price. It is too science that we look in the area of prevention, here there are a few possibilities. Male circumcision provides a degree of protection for men. A microbicide, a substance that could be inserted into the vagina prior to intercourse that would kill viruses and bacteria would be female controlled and highly beneficial. A number are being tried. But the first prize would be an effective vaccine.
In 1983 when the virus was first isolated the then US Secretary of Health and Human Services announced confidently that a vaccine was imminent. This proved to be widely optimistic and in my book I said: “Despite rapid scientific advances there are no simple solutions. There will almost certainly not be a vaccine available by 2015 the date the Millennium Development Goals were to be met”. At the time of writing there were just four pharmaceutical companies with vaccines in trials; only one candidate had gone through all trials and it was not effective.
The news over the past week of developments in Thailand is extremely significant. The US Military HIV Research Programme and Thai Ministry of Health announced that a ‘combination of two vaccine candidates’ is at least partially effective in preventing HIV transmission. It was reported that the combination is 31% effective at preventing infection with HIV. Clearly this is not were we need to be but it is a breakthrough. More information will be given on 20th October this year at an AIDS vaccine meeting in Paris.
At this point those of us working in the field of HIV/AIDS are encouraged. It is in the words of the International AIDS Vaccine Initiative’s Chief Executive “a significant scientific achievement. It is the first demonstration that a candidate AIDS vaccine provides benefits in humans”. It will lead to new investment and energy in the development of vaccines.
Although an effective vaccine is still some years off, there is at last good news on this front.