Identity can often be a matter of a bunch of numbers. Like a well-kept code, it is often best not to let others know yours.

Mr. Su, 42, has, in the vast network of systems of social management, some numbers that you and we all also have, but also some numbers ordinary people rarely see, and that Mr. Su would much rather do without. Four years ago, he was imprisoned for the first time for narcotics use. Like all convicts he was called only by the number sewn onto his uniform, not his name. Sadly, as with 60% of drug users, 300-plus days of struggling against addiction did not allow him to break free. After coming out he started up again with heroin.

"Last year I shot up an average of probably three times a day, 10 cc each time," says Su, who today runs a breakfast shop in Taoyuan County. He says that he doesn't worry much in winter, but in summer it's short-sleeve weather, so he injects into his feet or groin instead. At least, he says, having opened his own shop he can keep his "stuff" on the premises, so that if he develops a sudden craving, he has the right "medicine" at hand.

In the shop on a typical day, people stream in and out, Mr. and Mrs. Su take turns on the griddle, and their five-year-old twin girls sometimes lend a hand. Each morning they can pull in several thousand NT dollars. "But it's never enough, no matter how much we make," says Su. Spending nearly NT$3000 a day on heroin, in just a few years they have gone through all their savings. That would be bad enough, of course, but fate has had much worse things in store for them than money problems.

Mrs. Su, who followed her husband into heroin addiction, was arrested just after the last Lunar New Year at a friend's house. After she was sentenced, during her physical exam prior to going into prison, tests revealed that she had been infected with HIV.

"Don't share needles, I understand that," says Mr. Su, torn between sorrow and regret. "I told her over and over. It's no problem to shoot up at home, but even I would never give her my needle to use." When the test results came back, Mr. Su--whose own test fortunately came up negative--never doubted his wife's fidelity. He assumed right from the start that she got it through shared use of a contaminated needle.

Compared to the cautious Mr. Su, who only injects at home and uses each needle only about three times, the diminutive 150-centimeter-tall missus sometimes invites friends over to shoot up together. Among the friends arrested with her was a woman who had contracted HIV, whom the police speculate was the source of the HIV transmission to Mrs. Su.

Reality at the margins

Compared to how tough most infectious disease germs are, the AIDS virus--the "Black Death of the 20th century," as it has been called--is extremely delicate. It dies virtually as soon as it leaves the human body. That is why it can only be transmitted by intimate contact such as sex. Indeed, since AIDS first emerged from the homosexual community in San Francisco in 1980, it has in the public mind always been inextricably linked to sexual behavior, and especially non-mainstream sexual activity. This remains true even today.

Nonetheless, just after the US Centers for Disease Control confirmed that HIV can be spread by sperm, cases of infections amongst blood transfusion recipients and amongst intravenous drug users (IDUs) also began showing up, revealing that blood is also a means of transmission. In fact, compared to the 5% infection rate that occurs in sexual activity, the rate of infection through blood contact is a frightening eight times higher.

In fact, in sexual activity, transmission can only occur if there is breakage in the mucous membrane, so it is only natural that the rate of infection is much lower. This also explains why gay men are a high-risk group: the mucous membrane is easily broken during anal sex, which is why the infection rate is so much higher than for vaginal intercourse.

In Taiwan as well, it held true early on that AIDS was closely linked to sexual behavior. Though the first case of transmission through drug use was reported as early as in 1988, the proportion of total cases accounted for by this source stayed at less than 2% for several years running. However, this began to change in 2003.

Through 2001 the number of reported cases of drug-associated infection remained in single digits. In 2002 it hit double digits for the first time, with 19 reported cases. But in 2003 this number rose to 86, accounting for 10% of all recorded cases, and since then the number has exploded. The 2003 figures in fact should have been a clear warning signal, because overseas experience indicates that when HIV begins to spread through IDUs, if immediate action is not taken, there will be geometric growth for years.

Out of control?

In 2005, AIDS numbers of all kinds skyrocketed, pushing the AIDS prevention network built up over the years to the breaking point. Steve Hsu-sung Kuo, director of the Center for Disease Control, admits, "The epidemic has gotten virtually out of control."

Worse yet, the surface numbers are always only the tip of the iceberg. According to a WHO study, worldwide about 3% of people use narcotics, of whom about 60% do so intravenously, for a total of about 72 million IDUs. About 12% of these will contract AIDS at some point. Moreover, in most countries, drug use, drug dealing, and the sex industry are closely linked, so that infected persons spread the virus through two channels--through shared needles and through sex.

In Taiwan, using estimates from the Ministry of Justice, among 130,000 intravenous drug users, there are perhaps 15,600 persons infected with the AIDS virus. Subtracting the 3662 cases already reported, there could be about 12,000 cases which have not yet surfaced.

An especially noteworthy feature of drug-associated AIDS is that it is much more likely to spread rapidly among the heterosexual population. In fact, "when addiction meets AIDS, the first problem you see is that the number of infected women increases dramatically," states Yang Shih-yan, a divisional director at the CDC. Among cases in Taiwan, though males infected through non-mainstream sex or promiscuous sexual activity have always constituted a majority (and even today, despite the rapid rise in infection through drug use, still account for over 65% of total cases), it is now common for the female sexual partners of persons infected with AIDS through drug use to contract HIV from their partners.

As a result, there has been a clear increase in number of infected women, from less than 5% of cases before 2003 to 12% in 2005. This is consistent with the experience in other countries.

"In cases like the Su couple, where both man and woman are intravenous drug users, the chance of infection is even higher because it can occur through both sexual behavior and sharing of needles, and often both people end up drawing the short straw," says Yang.

Another aspect of the drugs-and-sex nexus is that some women engage in prostitution in order to support their drug habits. They thereby become highly mobile sources of infection, and are a major challenge for the prevention net.

Professor Szu-hsien Tony Lee of the National Defense Medical Center began a major long-term study in 2004 tracking 270 women who had been amphetamine or heroin users. He discovered that over 32% of these female addicts traded sex for drugs or money. These "candy babes," as they are known in Chinese, had as many as 30 to 50 sexual partners in six months.

And after the infection rate rises among women, the next thing that happens is vertical transmission from mother to child. According to WHO statistics, there are 2.5 million pregnant AIDS victims worldwide, and in 2004 630,000 AIDS babies were born. Prevention of vertical transmission from mother to child has now become one of the central pillars of UN AIDS prevention work. With this in mind, on World AIDS Day in 2004 Taiwan's Department of Health began offering free HIV testing to pregnant women. In 2005 almost 250,000 women were tested, discovering 28 carriers. As for AIDS babies, "Thus far the number of cases has been in single digits," says Yang Shih-yan, "and in fact Taiwan has only had a total of 13 cases in all, so things are not too bad yet."

However, the figures conceal a lurking danger. As Ivory Lin, secretary-general of the Persons with HIV/AIDS Rights Advocacy Association of Taiwan, warns, "If we don't act now, Taiwan, which has seen annual increases in the infection rate of over 10% every year since 1997 and which is now listed by the UN as a high-risk area for AIDS, is really going to find itself in big trouble."

In a protected, isolated location, an AIDS baby pulls apart the curtains in search of the light. According to the WHO, every year over 600,000 AIDS babies are born, in all regions of the world and across all levels of development. These infants are now on the front lines of AIDS prevention work for many governments.

Enemy at the gates

The worsening epidemic and the foreseeable consequences have the whole public health system in a siege mentality. How does the system respond?

For all cases of HIV infection, whatever the origin of the report, the CDC opens a new file and notifies the relevant township health authorities. "Whether the victim's legal address or just current address is here, we will keep track of them," says Tsai Pei-ling, a public health nurse for Liuchia Township Health Center in Tainan County. "We even know about all the cases in the prisons within our jurisdiction."

Liuchia, with a population of only 25,000, has 19 reported cases, of which only one is a local resident--the others are all in the nearby military prison. "The infected men are mostly around 20, and most are in for narcotics offenses; it was only from the pre-imprisonment physical that they found out they had contracted HIV," says Tsai. Although these AIDS victims are kept separate from the other prisoners, they pose many special challenges for the prison administration, from the depression suffered by the victims themselves to the physical and psychological security of prison staff.

Having been into the prison many times to advise victims and staff, Tsai can offer numerous insights into the habits and customs of IDUs, helping to explain how the infection spreads in this subculture.

When shooting up, the majority of IDUs will, after inserting the needle into a vein, "backdraw" blood into the syringe to make sure that they really have hit the vein. The reason is that if drugs are injected into human tissue outside the bloodstream, they will be absorbed by the liver, dampening the high. Some users will also, after injecting the mixed drug-and-blood in the syringe into their vein, again backdraw and reinject, repeating the process several times to make sure that they have gotten all the drugs out of the syringe and into their body. Thus, to maximize the high, "backdrawing" has become an essential, even ritualistic, part of drug use.

The problem is that with "backdrawing" the user's blood contaminates virtually 100% of the syringe and needle, so that effective sterilization becomes almost impossible. Use of either by another person can easily lead to transmission of disease.

Ignorance of such facts is widespread. Tsai notes that while "some drug addicts are really particular about the length or flexibility of needles, and there is even brand loyalty--they won't use any other hypodermic gear if it's not that brand--many addicts know pathetically little about avoiding HIV infection. Some people understand not to share needles, but then they'll get infected by sticking their own needle into an already contaminated "diluting cup" (a small plastic cup used for mixing powdered drug with a liquid injection medium to make injection easier).

While some addicts are simply uninformed, in other cases there are social or cultural reasons why precautions are not taken, thereby enabling HIV to spread.

For example, "Gang leaders shoot up with their followers, couples inject together, and people in a circle of addicts often share needles. This is a sign of their mutual fealty, a bonding ritual. In this kind of atmosphere, no one will dare to bring up AIDS as a reason for refusing to shoot up," suggests Yang Shih-heng, director of National Chung Cheng University's Crime Research Center. "Now that there is an ever-stronger connection between AIDS prevention and efforts to control drug abuse, there is a need for the police and the medical community to better understand this subculture."

If you can't beat it, guide it--that's the core idea behind harm reduction. Since all prostitution has become illegal in Taiwan, sex workers, trying to keep out of the way of the state, often constitute a major gap in AIDS prevention work.

Mysterious bond

In recent years the numbers for confiscated narcotics have been going up in parallel with those for infections among drug addicts, with both showing sudden increases to new peaks. Before 2002, the annual amount of seized narcotics remained steady at around 2000 kilograms per year. But in 2002 that figure suddenly quadrupled, reaching over 8000 kilos. This was just about the same point in time as the steep increase in drug-associated AIDS.

"There's not only a time connection, you can also see clues to the high interconnectedness between AIDS and drugs in Taiwan geographically," says CDC deputy director-general Lin Ting. HIV-1 is the strain of HIV most often seen in Taiwan, and it is also widespread in southern China. "You can draw a line through the zone in which it is most prevalent, from Yunnan all the way to Taiwan, virtually duplicating the drug-trafficking route."

With the drug problem worsening, the police are stepping up their crackdown. "A few friends of mine who use drugs have told me that the police even go so far as to stop people in front of drug stores, or even ask the pharmacies to give them leads, so that they can look for drug addicts from among the people who buy hypodermic paraphernalia," says Max Lai, secretariat administrator of the Taiwan Tongzhi Hotline Association. "If this is the way they do things, then it becomes harder to get needles and syringes, which previously circulated without any restrictions, and this naturally increases reuse and sharing of needles and diluting cups."

According to the Department of Corrections of the Ministry of Justice, there are currently an estimated 210,000 drug users in Taiwan, of whom 130,000 take intravenous drugs like heroin; the others mainly use "soft drugs," like marijuana or the recently faddish Ecstasy.

But even soft drugs, despite not being injected intravenously, also contribute in their own way to the spread of AIDS. "Soft drugs are very popular in the gay community," explains Max Lai. "Unlike heroin, Ecstasy causes a surge of sexual desire, especially in a party setting. A lot of people take Ecstasy and then have unprotected sex, and the result is the same--they contract HIV."

Harm reduction

From public health education to treatment, Taiwan spends NT$1.3 billion per year fighting AIDS. One of the most successful results of this investment is that 74% of all persons known to have been infected with HIV are now receiving pharmacological treatment, and the ten-year survival rate has been raised to 84%. However, the results of education in prevention have been less than satisfactory.

In a survey conducted last year by the CDC, among university students (who are at an age and in a social setting in which they are becoming increasingly sexually active) less than 30% use a condom every time they have sex. And among female sex workers, a very high-risk group, 86% said they don't dare to, and do not, ask that their clients wear condoms.

With respect to IDUs, in order to minimize sharing of needles, last year the Department of Health instituted a "harm-reduction" program, under which they began providing clean needles at 200 locations in Taipei County and City, and Taoyuan and Tainan Counties. During the trial period, the DOH also broke new ground in getting agreement from the police and investigative agencies to not take needles as evidence of drug use. The program will be implemented nationwide starting this July, and it is estimated that 10 million needle and syringe sets will be issued.

Though there has been a shift in the tools of AIDS prevention from handing out condoms to handing out needles, the core concerns of prevention work have not, at least in the eyes of some, changed at all. "Why do AIDS victims have to have their privacy rigorously protected?" asks Ivory Lin. "It's because once their identity is revealed, the way society looks at them will damage their rights to education, employment, and health care. And if as a result they don't come forward, prevention and treatment become very difficult, which will create even more problems for society."

"So if you really think about it, the question of rights of AIDS victims is not simply a question of protecting the human rights of a disadvantaged group, it is also essential to preventing the spread of the epidemic. If you don't protect them, then everyone will lose."

At this Christian church in Yungho, the pastor tries to help drug abusers using the power of religion. But there are not many clinics like this that help addicts kick the habit, so even if they want to quit, most addicts have nowhere to turn.

A network of trust

Besides getting those persons who are already infected to reveal themselves, it is also essential that those not yet infected but at highest risk get informed as quickly as possible. Unfortunately, as Wang Jen-hsien, an expert in infectious diseases in the Department of Medicine at China Medical University Hospital, who has been involved in AIDS treatment for 12 years and regularly gives talks on the subject around the island, relates, "Those who come and listen attentively to my lectures are all people with low-risk behavior. I should be giving classes to bar girls, johns, and addicts. But they would definitely never come. So what can you do?"

The lack of access to the IDU and sex worker subculture also hampers development of an HIV vaccine, work on which has been continually going forward as the AIDS threat has grown. "Immunization development requires a sufficiently large sample of clinical cases, but pharmaceutical companies hit the same bottlenecks that AIDS prevention work does," says John Yang, medical director of Merck Sharp and Dohme (IA) Corporation, Taiwan Branch. Determining the effectiveness of a vaccine requires testing on high-risk groups, but these are the people who stay in the shadows, so the lack of clinical testing is a tremendous drag on the R&D process.

Living with viruses

Rethinking the problem at its most fundamental level, there have recently been some new ideas from the medical community.

Not long before the HIV virus appeared, in October of 1977 the last reported case of smallpox on Earth completed treatment, making it the first virus in human history to be completely eradicated. For quite some time thereafter, many doctors and scientists fully expected the eradication of other viruses. But the job has proven to be much tougher than anticipated.

As CDC director Steve Kuo explains, "There has been a rethink in the public health community that perhaps we don't have to eradicate viruses, but should figure out how to coexist with them." He adds, "There is also a very humanistic aspect to this idea of coexistence. In order to ensure that persons infected with viruses are not demonized by society, we also need an attitude of 'coexisting with victims.' In the past, social pressure forced both drug addicts and AIDS victims underground, but now we have to encourage them to come out."

This is the key to success in the struggle against AIDS.

After a drug raid, a police station displays its haul of cash and drug paraphernalia like needles. In the eyes of street cops, needle possession is like an admission of narcotics use, so many users are afraid to be seen buying new needles.

If "harm reduction" is to succeed, basic law enforcement is critical. The photo shows a drug gang being taken back to the police station after a bust.