Friday, June 5, 2009

HIV/AIDS: A cure remains elusive but we can still effectively combat the pandemic

When it comes to HIV/AIDS which currently infects an estimated 33 million people worldwide – with indirect severe consequences on the lives of many times over the above figure – people are compelled to ask questions, “Is there a cure?”, “When shall we have vaccine against AIDS?”, questions which even legions of scientists trying to unravel the mysteries of HIV are not comfortable enough in providing the answers.

The fact is, no scientific breakthrough can yet help an HIV infected person completely get rid of the virus from his body system, which we term as ‘cure’. And these scientists, whom many consider as ‘magic workers’, are reluctant to disappoint humanity with the second best answer they have: yes the condition is treatable and is quite responsive to treatment at least for a certain period of time.

Challenges the scientists faced are these. HIV is a retrovirus that turns its RNA into DNA which it splices directly to the DNA of the infected CD4 T-helper lymphocyte of the host, giving independent instructions. It targets, infects and cripples the CD4 T-helper lymphocyte, the cell vital in fighting back against infections. It’s difficult to fight against an enemy that hides within our own primary arsenal.

The virus also changes its DNA so often and so rapidly that it’s like the body encountering a new bug every time it does so, making it difficult to develop effective and permanent drugs against it.

Let’s look for another alternative, the AIDS vaccine. AIDS vaccine, in general, is a substance that is introduced into the body, so that the body can defend itself against HIV by creating an immune response by making antibodies and/or killer cells against the HIV. The success of vaccine depends on its effectiveness and safety. Unlike smallpox or hepatitis B vaccines, all the experimental AIDS vaccines fail to fulfil the first requirement. The reason is HIV has a property of extreme genetic variation which occurs as a result of its rapid-fire replication rate once it is inside a human. In a single HIV-infected person, about 10 billion new HIV particles are formed every day. On the way HIV makes several mistakes – like that of a typing error one makes by hitting the wrong key while in a hurry – giving rise to accumulation of new strains of the virus having totally different genetic sequence, a condition called ‘mutation’. This variation pose a significant challenge to AIDS vaccine researchers, because the new strains of the virus can easily evade the existing antibodies induced by the AIDS vaccine in the body. The antibodies produced against the earlier strains do not work against strains that appear later. So, even when effective vaccines against certain strains of HIV can be developed, a greater number of variant strains will still escape unharmed.

Considering all these stumble-blocks, ‘prevention’ appears to be the most desirable method we can adopt to effectively combat the pandemic. Here are my suggested HIV prevention strategies:

Prevention of Sexual Transmission: Sexual networking patterns like commercial sex, polygamy, and multiple relationships minus consistent condom use encourages the spread of HIV. Culturally accepted dry sex, wife inheritance and initiation rites also add to the problem. The global AIDS epidemic is driven by men because men have more opportunity to contract and transmit HIV, hence implementation of male circumcision programme and consistent condom use will contribute significantly to HIV prevention. Either abstinence or fidelity as preventive measures should also be encouraged. The power of openness in the form sex education must also be realized, as evidence shows more talk about sex leads to less sex act. Reformation of the social structure in favour of women empowerment through appropriate government action is the need of the hour.

Prevention of Mother-to-Child Transmission: One of the tragedies of AIDS is that without protection, roughly one-third of babies born to HIV positive mothers will be infected while in uterus or during birth or through breastfeeding. Reduction of mother-to-child transmission rely on voluntary counselling and testing to identify mothers who are HIV positive, and on adopting these intervention options: (a) short-course antiretroviral (ARV) to the mother during pregnancy and labour and also to the baby and mother afterwards, which reduces the transmission to babies from 40% to 70%, (b) Caesarean Section at term before onset of labour, (c) prevention of early rupture of membrane during labour, (d) breast feeding practice, such as total formula feeding from start, or exclusive breast feeding and then weaning at 3-6 months, or heating expressed breast milk.

Prevention of Blood-borne Transmission: Transfusion of HIV contaminated blood is the most efficient mode of HIV transmission. This can be prevented by through screening of blood and by avoiding unnecessary transfusion. HIV transmission among injecting drugs users and hospital patients can be reduced by adopting needle exchange programme. Health workers can lessen their chance of acquiring the virus or of infecting their patients by taking universal precaution through use of masks, goggles and gloves during operation, injections and handling a patient’s blood or secretions. Chances of acquiring HIV after needle-stick injury and other occupational exposures can be lowered by a four weeks ARV course of post-exposure prophylaxis (PEP) starting within 72 hours of exposure. Best is to avoid injury by using biohazard sharp boxes where needles are disposed off un-recapped soon after use.

Voluntary Counselling and Testing (VCT): Well-informed people always know how to behave in times of crisis. VCT Centres help infected people know their HIV status long before they become sick. It encourages openness about the epidemic and hence acceptance. It enables infected pregnant women to reduce transmission risk to their babies by taking timely preventive measures.

Having said these, it must also be realised that prevention programme alone without care and support component will, at best be seen as partial response. It may lose credibility and support. Availability of care component earns the much needed community initiatives and support. Above all, the most acceptable and effective contributions always come from the HIV positives themselves through positive prevention programmes. It’s time we join hands together to face the scourge.