Last month, scientists invented the AIDS vaccine. Missed it? Perhaps thatâ€™s because you were still seeking the vaccine fantasy: the magic bullet, the impenetrable shield that finally pitches this disease into the trash bin, the shot that will end not only the AIDS epidemic but our anxiety about the AIDS epidemic as well.
The vaccine thunderbolt didnâ€™t strike â€” and might never. Drearily, the real AIDS vaccine is likely to be imperfect: one more tool in our arsenal, to be used along with condoms and all our other tools. It will most likely avert millions of infections and save millions of lives. But it will not end the Age of AIDS.
The vaccine that arrived last month was not actually a vaccine. It was, instead, a confirmation of what scientists had long suspected: circumcision helps protect men from AIDS infection. For years, AIDS researchers have observed that many African tribes that circumcise boys or young men had lower AIDS rates than those that donâ€™t, and that Africaâ€™s Muslim nations, where circumcision is near universal, had far fewer AIDS cases than predominantly Christian ones. The first research proof came in 2005, when a study in South Africa was stopped early in the face of evidence that the men who had been randomly assigned to be circumcised were getting 60 percent fewer H.I.V. infections than the men assigned to the control group. Last month, ethics boards halted two similar studies, in Uganda and Kenya, when they found similar results. In both, the circumcised men caught the AIDS virus half as often as the uncircumcised control group.
Circumcision would be given more weight if the world recognized that it is, in fact, the real-world equivalent of an AIDS vaccine. In some ways, it is closer to the fantasy than a real vaccine might be. Vaccine research began in the early 1980s but with little financing or urgency and went nowhere. In 1996, the effort was revived with the creation of the International AIDS Vaccine Initiative, and financing has soared in the last five years. But a vaccine has proved elusive. Most vaccines work by mimicking infection, which stimulates the body to make antibodies that kill the disease. But H.I.V. infection generally does not produce those kinds of antibodies. H.I.V. also mutates constantly and comes in many different varieties, factors that further complicate the search for a vaccine.
Many vaccines provide nearly 100 percent protection â€” after my daughters finish their two doses of the measles, mumps and rubella vaccine, for example, they wonâ€™t have to think about those diseases again. But thatâ€™s not on the horizon for AIDS. â€œFifty to 60 percent efficacy is what people would feel really good about,â€ says Frances Priddy, the director of efficacy trials with the AIDS vaccine initiative. The best candidates in the vaccine pipeline right now â€” which wonâ€™t be ready until 2013 at the earliest â€” wouldnâ€™t keep you from getting H.I.V. They instead would seek to change your bodyâ€™s response to the virus so that if you did get infected, the disease would progress more slowly â€” or not at all â€” and you would be less infectious to others.
An efficacy rate of 50 to 60 percent is actually a lot better than it sounds, because of herd immunity. We get AIDS from one another. Every time a person is rendered less infectious, the chance of an uninfected person catching H.I.V. from each sexual contact drops, and in a virtuous circle, the whole community becomes progressively safer. A vaccine of 50 to 60 percent efficacy might come close to wiping out the epidemic in places with low AIDS rates. In high-prevalence areas, it could reduce the epidemic and save millions of lives.
In contrast to a vaccine, circumcisionâ€™s origins are about as far from the laboratory as you can get; carvings depicting circumcisions have been found in ancient Egyptian temples. But the effects may be very similar to those of a vaccine. So far, we have proof only that circumcision protects the circumcised men. But there are strong indications that it also protects their sexual partners. A trial in Uganda is now testing whether H.I.V.-positive men are less likely to infect their wives if they are circumcised than if they are not.
Together, circumcision and an imperfect vaccine might be enough to stop AIDS. But they will need help from behavior change, microbicides, fighting malaria, treating genital herpes and other interventions we donâ€™t even know about yet. That is unsatisfying. The danger does exist that circumcised men will feel invulnerable and throw sexual caution to the winds, a risk that would also exist with an imperfect vaccine. But so far, there is not much evidence of a problem. In the Uganda and Kenya studies, the sexual behavior of the circumcised men was no more risky than that of the others. In the South Africa study, circumcised men did report 25 percent more sexual activity. But the circumcised group as a whole still had 60 percent fewer infections. Certainly one reason that risky behavior did not jump is that the men got counseling as part of the clinical trials. Counseling goes naturally with circumcision; counseling would be harder to include in a vaccine campaign, since one of a vaccineâ€™s great advantages is that it can be given assembly-line-style in seconds.
Circumcision is a surgical procedure, however, and in the hands of traditional ritual circumcisers, it has a high rate of infection and mishap. The solution is to train these circumcisers and give them decent tools, and at the same time encourage men to come to clinics. Since men in studies say that cost is the biggest reason they are not circumcised, the operation must be free. Countries will also have to equip these clinics and train counselors and medical circumcisers, who donâ€™t have to be doctors.
Research on an AIDS vaccine is more crucial than ever. But we must not let our hope for a thunderbolt prevent us from racing ahead with circumcision now. For the biggest difference between circumcision and a vaccine is this: only one of them exists.
Source:The New York Times