There have been suggestions that HIV may not be the cause of AIDS, and that the AIDS epidemic in Africa is a myth. This has in part been due to the claims of a US scientist, Professor Duesberg, who has promoted the view that HIV is relatively harmless, and that AIDS is caused by recreational drugs or other causes of immune damage. Connected with this has been the claim that anti-viral drugs are useless, even in those with AIDS---indeed that they actually causes AIDS.
Considering how poorly these claims are supported by scientific data, how very few other scientists take them seriously and how damaging the claims are to the health campaign, it is surprising they have been given such sympathetic reaction by some people. Underlying most of these claims is a conspiracy theory involving alleged multinational fraud by research workers and drug companies, with the collusion of governments and the World Health Organisation. Trying to discuss the issues with some of these people is hard work. They rarely have scientific credentials themselves of any note, and have an almost messianic fervour in devotion to their cause.
Remember you can write an apparently well-researched book to make a case for almost any bizarre theory by selective quoting of scientific papers, just as you can make a bizarre religion out of twisting bible sayings out of context. Even more so with scientific literature since it so vast each month, so variable in quality and in results. 50 scientists conducting similar studies over a decade do NOT report the same results. There are a hundred reasons for variations. The truth is gained by studying the consensus, although media headlines are almost always built out of single findings which suggest something different from most studies. Much of the scientific literature is complex and easy to misunderstand.
I am asked for clarification almost every week by well-informed people who are deeply puzzled. The confusion is dangerous too. At a recent International AIDS Conference I was handed a leaflet by an AIDS activist titled `HIV is good for you'.
Here is a brief summary of some of the reasons why almost all scientists working in the AIDS field are totally convinced that HIV is a highly dangerous infectious virus causing AIDS.
1. The appearance of AIDS always follows HIV spread. In every group studied we have seen the rise in numbers ill with AIDS closely linked to the increasing spread of HIV infection some years earlier.
Example: In Edinburgh rapid spread of HIV among drug users was followed by a steady rise in those ill or dying. In Glasgow, drug users of similar age, background and lifestyle were much less affected by HIV (HIV hit Glasgow later and behaviour changed in time) and death rates have been much lower. Incidentally, scientific studies have shown that nitrites and other recreational drugs do not cause AIDS.
Example: In many parts of Africa people have died from illnesses such as tuberculosis in large numbers for decades. However, a large rise in deaths in the sexually-active age group has followed spread of HIV into this group, with death rates in two years sixty times higher in those with HIV.
Some have claimed that HIV has been present at similar levels for decades. This is nonsense. HIV levels in most towns and cities in many nations show rapid year-on-year rises took place during the 1980s and early 1990s. Indeed, one study in 1986 found HIV levels as low as 1 in 1,000 in some groups, rising since.
Some have claimed that there is no massive AIDS epidemic in Africa and that HIV is being blamed for deaths of people who would have been dying anyway. It is true that diagnosis of AIDS in an individual in Africa can be difficult, as we saw in Chapter 3, but the fact is that death rates in the younger age groups are unexpectedly high---and among babies of those infected too. Babies testing positive a year after birth become ill later with AIDS. Those testing negative do not.
Many Africans arriving in countries like the UK with HIV, who become ill and die, clearly have an identical illness to those with AIDS infected in industrialised nations.
Some say there is a cross-reaction between malaria antibodies and HIV tests. As we saw in the earlier question on test accuracy, this was a problem in the mid-1980s, but not today. It is obvious anyway that malaria confusion is not taking place on a wide scale. The numbers in the population with malaria antibodies have remained relatively constant, while the numbers testing positive for HIV have soared. And HIV is found in many areas where there is no malaria.
Great weight has sometimes been placed on comments by some African specialists and politicians that the AIDS problem has been exaggerated by the West and that the actual size of the epidemic is far less significant than has been made out. Unfortunately, almost all doctors and nurses from European and other nations working in government and mission hospitals give a different story, based on first-hand experience of the unfolding catastrophe. Many African experts are not free to talk about AIDS, for reasons we saw in Chapter 1. Indeed, many Western doctors in these nations may also find it difficult to talk until they go home on leave.
Example: Those with haemophilia have received blood extracts for many years without problems. However, once HIV contaminated their supplies those testing positive for HIV began to grow ill and die - as did in some cases their wives and children. Some have claimed that these haemophiliacs are only ill because the blood extracts of Factor VIII are rejected as foreign to the body and damage their immune systems. Evidence quoted in favour of this is from unpublished early reports that haemophiliacs with HIV are progressing more slowly to AIDS when converted to pure genetically-engineered Factor VIII. However, if Factor VIII is the sole explanation, why are uninfected people who have been receiving impure blood extracts for years not developing AIDS? We would also expect those receiving HIV in a blood transfusion to remain perfectly well when the fact is that they become ill and die too.
Anyone can see the links: a woman receives a pint of infected blood and becomes infected. Six years later she is unwell. Her baby is infected and develops AIDS and so does her husband. But no one else in her family dies. Why? Because a lethal infectious agent which we call HIV has been transmitted from blood to person, to partner and to baby. In fact these facts are so obvious and so simple to understand that it is extraordinary to me that anyone of even moderate intelligence should insist that there are other explanations.
Example: As we have seen, mothers can transmit HIV to their babies through the womb, during birth and in breast milk. These babies get ill and die of AIDS. Those who do not become infected remain well throughout life. Remember of course that we are not talking here about babies falsely testing positive to HIV because the result is confused by maternal antibodies.
2. The pattern of HIV spread fits AIDS pattern. If HIV is the cause of AIDS, we should expect to find that HIV shows evidence of spread through sexual activity and through the blood, since we know people with AIDS are linked by such contact. This is indeed what we find, with overwhelming evidence of person-to-person spread of HIV by these routes.
3. HIV targets the cells which are damaged in AIDS. Some have tried to make a case that HIV is just an innocent passenger, not causing illness but just travelling with whatever does do the damage. However, the more we study HIV the more we understand how dangerous it is.
We know that HIV gets inside the same white cells whose death results in AIDS. We know that after an initial brief illness, HIV goes on multiplying in lymph nodes, where large numbers of infected cells can be found throughout the symptom-free period. We know that as virus levels rise, the person becomes more ill. We know that HIV attacks some cells in the brain and in the gut directly, explaining why people with AIDS can have damage to both organs. Although early studies have suggested that only one target white cell in 10,000 becomes infected, more sensitive tests have now detected HIV infection in one in ten cells.
4. Anti-HIV treatments benefit those with AIDS. If HIV is the cause of AIDS, then we would expect drugs used to fight HIV to produce an improvement in those who are ill. As we have seen in Chapter 2, there are a great number of independent studies which show that the anti-viral drugs improve the condition and survival of those with AIDS when used appropriately. It is true that they have side effects, and it is also true that resistance to the drugs can make treatment less effective after a while. As this happens, CD4 cell levels fall, virus levels rise and the person often begins to deteriorate. This is all evidence of linkage.
The simple fact is that babies of mothers with HIV are far less likely to die of immune deficiency if their mothers have been given anti-virals during late pregnancy. Why? Because anti-virals lower the levels of HIV in the mother's blood and this helps save baby's lives. The HIV-does-not-cause-AIDS groups say that anti-virals actually CAUSE AIDS, and do not prevent it. This is a ridiculous conclusion to draw from our experience of caring for babies. It is also equally absurd when it comes to adults. These people fail to recognise that all over the world there are people dying with AIDS who have never had the luxury of anti-viral treatment, and even in wealthy nations there are people who have been diagnosed late so not treated before becoming very ill, or who for one reason or another were unwilling at any stage to be treated. They still get ill and die.
Great play has been made by a minority on the discovery of a very small number of people who seem to have an AIDS-like illness with no evidence of HIV infection. I am not referring here to those who for various reasons lose or never develop an antibody response, but those in whom HIV is never found, even with many different detection methods.
There are two explanations for this, neither of which destroys the HIV basis for AIDS. First, we sometimes fail to look hard enough. Even in an illness like TB, it is not always possible to find the organisms. In other very rare cases it appears we are looking at a very rare form of immune problem that has probably been around for centuries, and is nothing to do with AIDS. Such cases account for only a few in a million of what gets diagnosed as AIDS. As we have seen in earlier chapters there are undoubtedly other factors which can cause acceleration or slowing of disease which might include other infections such as mycoplasma and the genetic makeup of the individual.
In summary then, there is overwhelming evidence that HIV causes AIDS, although, as with the link between smoking and lung cancer, much of it is circumstantial, based on large-scale studies of disease patterns. Just as you cannot PROVE that smoking causes lung cancer, or that a cancer in a particular person was caused by smoking, you cannot PROVE that HIV causes damage to the immune system or that a particular person dying with TB is dying because HIV has weakened their defences. The nature of medical research is to look for patterns that fit everything else we understand about illnesses. If we accept (as most people do without question) that smoking is dangerous, then exactly the same logical process forces us to conclude that HIV causes AIDS. The evidence is before the jury, and the result is conviction. The evidence is beyond all reasonable doubt.