Bad news in the fight against the AIDS virus: The government is halting a large U.S. study of a possible HIV vaccine because the experimental shots aren't preventing infection.

The study had enrolled about 2,500 people, mostly gay men, in 19 cities. Half received an experimental vaccine developed by the National Institutes of Health, and half received dummy shots.

A safety review this week found that slightly more volunteers who had received the vaccine later became infected with HIV. It's not clear why.

The NIH said Thursday that it is stopping vaccinations, but will continue to study the volunteers' health.

Multiple attempts at creating an AIDS vaccine have failed over the years. But researchers continue to try, pointing to modest success in a 2009 study in Thailand.

Citing the scope of a public health scare involving thousands of patients of an Oklahoma oral surgeon, the head of the state's dentistry board said Monday she wants prosecutors to consider pursuing criminal charges.

Nearly 1,000 of Dr. W. Scott Harrington's 7,000 patients have now been tested in Tulsa for hepatitis B and C as well as HIV, the virus that causes AIDS. About 400 people showed up at a clinic north of downtown Saturday, the first day the free tests were offered, and nearly 560 people showed up Monday.

Susan Rogers, the executive director of the Oklahoma Board of Dentistry, told The Associated Press that she talked with Tulsa County District Attorney Tim Harris on Monday to discuss whether Harrington is criminally liable.

"We're looking for the witnesses and individuals who can testify for us that this is what happened to me in (Harrington's) office," Rogers told AP.

The 17-count complaint filed last week by Rogers' office called Harrington a "menace to the public health." The complaint also said officials found rusty instruments, potentially contaminated drug vials and improper use of a machine designed to sterilize tools at Harrington's two Tulsa-area offices.

Harrington and his staff could face at least two felony charges, Rogers said, including practicing dentistry without a license and aiding or abetting another person who is violating the state's dental act. Rogers said each possible charge could carry a prison term of up to four years and a $10,000 fine.

"I did speak to the DA this morning and I've talked to other officials, and I can't comment on those conversations, but there's more to come," Rogers said.

A spokeswoman at the district attorney's office could not comment Monday because prosecutors haven't received any paperwork from the dentistry board. A message left Monday morning with Harrington's attorney in Tulsa was not immediately returned.

Harrington had been a dentist for 36 years before voluntarily giving up his license March 20. He faces an April 19 hearing at which he could have his certification revoked.

Letters have been sent to 7,000 patients, urging them to be screened for hepatitis B and C and the virus that causes AIDS. Those letters should arrive no later than about two weeks, Kaitlin Snider, spokeswoman for the Tulsa Health Department, said Monday.

"We are here for the long haul," Snider said. "We know we can't screen 7,000 patients in a day or even in a week."

Those who have been tested should receive their results within two weeks, she added.

According to the Oklahoma Dentistry Board's complaint, Harrington's practice had varying cleaning procedures for its equipment, needles were re-inserted in drug vials after their initial use and drug vials were used on multiple patients.

Also, dental assistants performed some tasks reserved to a licensed dentist, such as administering IV sedation. A device used to sterilize equipment hadn't undergone required monthly tests in at least six years.

"When this started, I had no idea it was going to be this bad or this broad," Rogers said Monday. "This one scared me."

The public alert began after a patient of Harrington's initially tested positive for HIV in a screening at a third-party provider. But more testing indicated that the patient was not positive for HIV, only hepatitis C, the Tulsa Health Department said Friday.

Court records show that Harrington was sued for medical malpractice in 1994, and the case was settled in 1995. He also was sued for negligence in 1997, which was settled out of court in the same year.

Hundreds of patients of an Oklahoma oral surgeon accused of unsanitary practices showed up at a health clinic Saturday, looking to find out whether they were exposed to hepatitis or the virus that causes AIDS.

Letters began going out Friday to 7,000 patients who had seen Dr. W. Scott Harrington during the past six years, warning them that poor hygiene at his clinics created a public health hazard. The one-page letter said how and where to seek treatment but couldn't explain why Harrington's allegedly unsafe practices went on for so long.

Background: Dentist's office a 'menace,' HIV tests urged for thousands

Testing for hepatitis B, hepatitis C and the virus that causes AIDS began at 10 a.m. Saturday, but many arrived early and stood through torrential downpours. The Tulsa Health Department said 420 people were tested Saturday at its North Regional Health and Wellness Center. Screenings resume Monday morning.

Kari Childress, 38, showed up at 8:30 a.m., mainly because she was nervous.

"I just hope I don't have anything," said Childress, who had a tooth extracted at one of Harrington's two clinics five months ago. "You trust and believe in doctors to follow the rules, and that's the scariest part."

Inspectors found a number of problems at the doctor's clinics in Tulsa and suburban Owasso, according to the state Dentistry Board, which filed a 17-count complaint against Harrington pending an April 19 license revocation hearing. According to the complaint, needles were reinserted into drug vials after being used on patients, expired drugs were found in a medicine cabinet and dental assistants, not the doctor, administered sedatives to patients.

One patient, Orville Marshall, said he didn't meet Harrington until after he had two wisdom teeth pulled about five years ago at the Owasso clinic. A nurse inserted the IV for his anesthesia; Harrington was there when Marshall came to.

"It's just really scary. It makes you doubt the whole system, especially with how good his place looked," said Marshall, 37.

An instrument set reserved for use on patients with infectious diseases was rusty, preventing its effective sterilization, and the office autoclave — a pressurized cleaner — was used improperly and hadn't been certified as effective in at least six years, according to the complaint.

Dr. Matt Messina, a Cleveland dentist and a consumer adviser for the American Dental Association, said creating a safe and hygienic environment is "one of the fundamental requirements" before any dental procedure can be performed.

"It's not hard. It just takes effort," he said.

Weekly autoclave testing can be performed for less than $400 annually, according to the website of the Autoclave Testing Services of Pearl River, New York.

Autoclaves typically can be purchased for $1,000 to $8,000, depending on their size and features. And an average dental practice can expect to pay more than $40,000 a year in equipment, tools and supplies alone, according to several dental organizations.

Attempts to reach Harrington have been unsuccessful. No one answered the door Thursday at his Oklahoma home, which property records show is worth more than $1 million. His practice a few miles away, in a tony section of Tulsa where plastic surgeons operate and locals congregate at bistros and stores such as Saks Fifth Avenue, has a fair-market value of around $851,000.

Property and tax records show Harrington owns another residence in Carefree, Ariz., in an area of upscale homes tucked into in the boulder-strewn mountains north of Phoenix.

Nobody was at home Saturday at the low-slung, 1950s-style vacation home, across from the Boulders Resort. Neighbors said they had seen a lot of activity at the home in recent weeks.

Harrington's malpractice lawyer, Jim Secrest II, did not respond to phone messages left Thursday or Friday. A message at Harrington's Tulsa office said it was closed and an answering service referred callers to the Tulsa Health Department.

Suzy Horton, an old friend of Harrington's, said she can't believe the allegations about the man who removed two of her teeth in the early '90s. Horton's ex-husband sold Harrington his home in Carefree — a home where she once lived.

"I've been to dentists my whole life, so I know what a professional office looks like," Horton, who now lives in Phoenix, said in a telephone interview. "His was just as professional as anybody."

Horton hasn't seen Harrington in years, but she said he has sent her a Christmas card and wreath every year since her 1999 divorce.

"It was a long time ago, so I suppose anything can change, but the kind of person they're portraying in the news is not the kind of person who sends you a Christmas" card, she said.

___

Associated Press writers Traci Carl in Carefree, Ariz., and Jeannie Nuss in Little Rock, Ark., contributed to this report.

The crisp, stucco exterior of an Oklahoma dental clinic concealed what health inspectors say they found inside: rusty instruments used on patients with infectious diseases and a pattern of unsanitary practices that put thousands of people at risk.

State and local health officials planned to mail notices Friday urging 7,000 patients of Dr. W. Scott Harrington to seek medical screenings for hepatitis B, hepatitis C and HIV. Inspectors allege workers at his two clinics used dirty equipment and risked cross-contamination to the point that the state Dentistry Board branded Harrington a "menace to the public health."

"The office looked clean," said Joyce Baylor, who had a tooth pulled at Harrington's Tulsa office 1½ years ago. In an interview, Baylor, 69, said she'll be tested next week to determine whether she contracted any infection.

"I'm sure he's not suffering financially that he can't afford instruments," Baylor said of Harrington.

Health officials opened their investigation after a patient with no known risk factors originally tested positive for both hepatitis C and HIV, the virus that causes AIDS. Further testing determined that the "index patient" was not actually positive for HIV, although was positive for Hep C, the Oklahoma Dept. of Health said Friday. Because Hep B, C and HIV are all bloodborne viruses, officials are still testing Harrington's patients for HIV, as well as Hep B and C.

The investigation began when it was learned the "index patient" had a dental procedure about the likely time of exposure. Investigators visited Harrington's office and found a number of unsafe practices, state epidemiologist Kristy Bailey said.

"I want to stress that this is not an outbreak. The investigation is still very much in its early stages," Bailey said.

Harrington voluntarily gave up his license, closed his offices in Tulsa and suburban Owasso, and is cooperating with investigators, said Kaitlin Snider, a spokeswoman for the Tulsa Health Department. He faces a hearing April 19, when his license could be permanently revoked.

"It's uncertain how long those practices have been in place," Snider said. "He's been practicing for 36 years."

The Centers for Disease Control and Prevention is consulting on the case, and agency spokeswoman Abbigail Tumpey said such situations involving dental clinics are rare. Last year a Colorado oral surgeon was accused of reusing needles and syringes, prompting letters to 8,000 patients, Tumpey said. It wasn't clear whether anyone was actually infected.

"We've only had a handful of dental facilities where we've had notifications in the last decade," Tumpey said.

The Oklahoma Dentistry Board lodged a 17-count complaint against Harrington, saying he was a "menace to the public health by reasons of practicing dentistry in an unsafe or unsanitary manner." Among the claims was one detailing the use of rusty instruments in patients known to have infectious diseases.

"The CDC has determined that rusted instruments are porous and cannot be properly sterilized," the board said.

Health officials are sending letters to 7,000 known patients but cautioned that they don't know who visited his clinics before 2007. The letters urge the patients to be tested for hepatitis B, hepatitis C and HIV — viruses typically spread through intravenous drug use or unprotected sex, not occupational settings.

Harrington could not be reached for comment Thursday. A message at his Tulsa office said it was closed, and the doctor's answering service referred callers to the Tulsa Health Department. Phone numbers listed for Harrington were disconnected. A message left with Harrington's malpractice attorney in Tulsa, Jim Secrest II, was not immediately returned.

Harrington's Tulsa practice is in a thriving part of town, on a row of some of medical practices. The white-and-green stucco, two-story dental clinic has the doctor's name in letters on the facade.

NBCLatino: You may have Hep C and not know it

According to the complaint, the clinic had varying cleaning procedures for its equipment, needles were re-inserted in drug vials after their initial use and the office had no written infection-protection procedure.

Harrington told officials he left questions about sterilization and drug procedures to his employees.

"They take care of that, I don't," the dentistry board quoted him as saying.

The doctor also is accused of letting his assistants perform tasks only a licensed dentist should have done, including administering IV sedation. Also, the complaint says the doctor's staff could not produce permits for the assistants when asked.

Susan Rogers, executive director of the state Dentistry Board, said that as an oral surgeon Harrington regularly did invasive procedures involving "pulling teeth, open wounds, open blood vessels." The board's complaint also noted Harrington and his staff told investigators a "high population of known infectious disease carrier patients" received dental care from him.

Despite the high-risk clientele, a device used to sterilize instruments wasn't being properly used and hadn't been tested in six years, the board complaint said. Tests are required monthly.

Also, a drug vial found at a clinic this year had an expiration date of 1993 and one assistant's drug log said morphine had been used in the clinic last year despite its not receiving any morphine shipments since 2009.

Officials said patients will be offered free medical testing at the Tulsa Health Department's North Regional Health and Wellness Center.

Related:

Dental chain accused of hurting kids, bilking taxpayers

This story was originally published on Thu Mar 28, 2013 4:06 PM EDT

Fourteen HIV patients who got quick treatment with AIDS drugs have been able to stop the treatment without the virus coming back, French researchers reported on Friday.

While it’s clear the patients are not cured, they may be able to continue healthy lives without the drugs, the researchers report in the journal PloS Pathogens. And their cases point to the importance of diagnosing and treating HIV patients as quickly as possible.

Earlier this month, doctors made headlines with the case of a Mississippi toddler who got a larger-than-usual dose of HIV drugs at birth when it turned out her mother had been infected and didn’t know it. Pre-treatment with the drugs can protect babies from infection at birth, and treating the mothers can further reduce the risk they will pass along infection.

The report about the 14 French patients supports the idea that, at least in some patients, quick treatment may prevent the virus from taking hold in the body.

Quick treatment may also stop the virus from mutating, said Asier Sáez-Cirión of Frances Pasteur Institute and colleagues, who wrote the report. The human immunodeficiency virus that causes AIDS is highly mutation prone, and this makes it hard both for the body’s immune system to control it and to make a vaccine against it.

About 34 million people are infected with HIV, the virus that causes AIDS, globally; 25 million have died from it. While there’s no vaccine, cocktails of powerful antiviral drugs can keep the virus suppressed and keep patients healthy. No matter how long patients take the drugs, however, the virus lurks in the body and usually comes back if the drugs are stopped.

Fewer than one percent of HIV patients somehow manage to control the virus on their own and can stop taking the drugs.

Sáez-Cirión and colleagues were trying to find out how they do it. They studied a database of 3,500 patients. About 1,000 of them had begun taking drug cocktails with 6 months of having been infected, and 70 stopped taking the drugs when the virus was brought under tight control. Some wanted a "drug holiday" and some were taking part in a trial of what's called scheduled treatment interruption -- a way to give patients a break from taking the drugs, which can have unpleasant side-effects.

They singled out 14 who got quick treatment in the late 1990s or early 2000s when they showed symptoms of HIV infection – a rash and fever, for instance. All of them responded very well and within three months the virus had been driven to “undetectable” levels. That means it is barely active and not replicating withing the body.

The patients were able to stop taking the drugs, stay healthy, and the virus stayed at low levels. Tests of their blood showed nothing really unusual, but the virus did not seem to be attacking the immune system cells, called CD4 T-cells, that it usually infects.

If a patient is able to stop taking drugs, doctors call it a "functional cure," even though the virus is still in the body and might come back years later.

“Our results show that early and prolonged (drug therapy) may allow some individuals with a rather unfavorable background to achieve long-term infection control and may have important implications in the search for a functional HIV cure,” the researchers wrote.

Only about 5 percent to 15 percent of patients who get quick treatment are able to control the virus this way, the researchers estimated. Everyone else starts getting signs of infection again when they stop taking the drugs. In these 14 patients, the immune system did not appear to be controlling the virus in the same way as the so-called elite controllers, the 1 percent of people who can do it naturally.

It's possible early treatment prevented the virus from hiding out in long-lived immune cells called viral reservoirs, they said.

“However, it remains unclear why only a limited fraction of patients is able to control the infection after therapy interruption,” the researchers wrote.

Doctors once recommended that patients with HIV not start treatment until they “needed” it – when the virus reached certain levels in the blood, or when the immune system showed a certain level of damage. Now that it’s clear that immediate treatment can keep patients healthier and stop them from infecting someone else, U.S. guidelines say all patients diagnosed with HIV should be treated.

Related:

• A baby now free of HIV has doctors talking
• Two more men are HIV-free
• AIDS conference opens with an eye to a cure

The case of a baby who may have been cleared of an HIV infection raises two tantalizing prospects: Is it possible to save even more newborns from infection, and is it possible that other babies may have been cured and no one knows it yet?

One thing that everyone agrees is clear: It's really too soon to say the 2 1/2-year-old from rural Mississippi is actually cured, and it's way too soon to change the standard ways that newborns are now treated to protect them from the virus.

Jim Watson / AFP - Getty Images file

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, speaks during the 19th International AIDS Conference in Washington, D.C., on July 23, 2012.

But researchers are already thinking about ways they can design studies to see if starting a full course of treatment in a newborn can prevent the 200 new HIV infections seen every year in U.S. babies and the more than 300,000 that happen globally.

“This is an important, but small step in the direction of understanding how we might better treat HIV-infected infants,” Dr. Anthony Fauci, who directs the National Institute of Allergy and Infectious Diseases, told NBC News.

The main goal, Fauci points out, is to prevent infection in the first place. Done right, standard procedures protect babies 95 percent of the time. If a woman has the human immunodeficiency virus that causes AIDS, she can start taking a cocktail of drugs right away that prevent her from infecting her baby in the womb or during birth. Newborns are given a light course of drugs, to, just to be sure.

If they get infected anyway, then the babies get a heavier, three-dose cocktail if drugs to keep them healthy.

The Mississippi baby’s case is unusual. Her mother showed up in labor and didn’t know she had HIV. The baby was a little premature, so she was kept in the hospital for longer than normal. That gave Dr. Hannah Gay of the University of Mississippi Medical Center a chance to deliver an unusually intense course of HIV drugs to the child right away.

This drove the infection down to what’s known as undetectable levels, meaning the virus isn’t active. But it’s always still there, waiting to come back unless the patient takes a cocktail of drugs every day. And if the mother hadn’t stopped bringing her baby to the hospital for several months, no one would ever have noticed something usual was happening in her infant’s body.

But she did. The mom disappeared twice, and missed at least eight months worth of treatment. So Gay frantically checked the baby when she did come back, looking to see how bad the infection was. When she couldn’t find any evidence of the virus, she called in help. That’s when other experts found, to their amazement, that there was virtually no trace of the virus left in the child – only apparently harmless bits of genetic material: DNA and RNA.

This case raises the possibility that giving newborns that drug cocktail sooner might not just keep them healthy,  but allow them to stop taking the medications altogether someday, said Fauci.

“If the baby does get infected, if you could treat them as early as possible you give yourself a much better chance of actually curing the baby,” Fauci said.

Experts stress that it is vital that parents who have HIV-infected children keep giving them the drugs. Taking kids or adults off the treatment can allow the virus to start replicating and damaging the immune system again.

Dr. Carlos del Rio, an AIDS expert at Emory University in Atlanta and a spokesman for the HIV Medicine Association, says he worries that some parents may stop giving HIV drugs to their children. “I worry about the general message to the public. We don’t have a cure for HIV,” he said.

“People shouldn’t be stopping their therapy Del Rio added. “I call this case a miracle. The great majority of babies in this case, if they had gone that long without treatment, would have had advanced HIV. This case is the exception rather than the rule.”

That said, it’s possible that some children who were treated as babies might be able to safely discontinue the drugs, said Fauci.

“Maybe we have actually been curing some people without even realizing it and we need to carefully look to see if there's virus there,” he said.

“You don't want to just decide you're going to stop therapy in children who are doing well. That would be a big mistake, but you should at least look at the possibility that maybe the virus is now absent or essentially no longer viable in those children.”

Other experts say they’ll be studying ways to change policies in developing countries where the AIDS pandemic is still blazing.

“We think this case has the potential  to change the way babies born with HIV are treated,” said Dr. Annette Sohn of amfAR (formerly the American Foundation for AIDS Research). “That means diagnosing them in the first few days instead of waiting a few weeks.”

Sohn, who heads an office in Thailand, says it will require a careful balancing act.

Right now, the main AIDS drug used is AZT, which is available very cheaply and which has few side-effects. It is given to newborns to protect them at about a third of the dose that would be given to them to treat an actual known infection.

The problems doctors have in treating newborns, as opposed to older children, come in testing them for infection and in balancing the benefits of drug treatment against the risks. AZT can cause anemia, so doctors are cautious about giving it to babies who don’t need it.

And HIV doesn’t cause any immediate signs of infection. It takes a while to take up residence in the body, and it takes a while for the body to mount an immune response. Most tests that are used to diagnose infection in people look for antibodies – the immune response to an infection, not the virus itself.

So doctors treating newborns may have to turn to a different test, one that looks for virus.

But Sohn says many clinics already do this. They just wait a few weeks. She thinks it may pay to just speed up the process, testing babies withing hours of birth.

“We are already using these virologic tests and we are already using these medications,” she told NBC News. “I think what we are proposing actually compresses the time frame for testing. We may not necessarily be looking at more testing per se."

She thinks many overseas AIDS programs could do this without spending much more time or money. “You’re either looking at investing up front, from birth, or investing in a lifetime of treatment,” she said.

In 2011, the United Nations AIDS agency UNAIDS reported that 330,000 children had been infected with HIV at birth. “If we can get them diagnosed by 12 weeks of age and started on treatment we can reduce the risk of death by 75 percent. But we are struggling to get these babies diagnosed,” she said.

This case, she said, will raise pressure on the UN and other authorities to step up programs to get pregnant women and their newborns tested earlier.

The picture is a little different in the United States, said Chip Lyons of the Elizabeth Glaser Pediatric AIDS Foundation.

“Most women get good care and are seen and are tested. Their status is known,” he said.  But in many developing countries, babies often aren’t even tested until they are six weeks old. This finding, he said, suggests that is far too long to wait.

Related stories:

• Case of HIV-free baby has doctors talking 'cure'
• Test of gel, pills to prevent HIV fails in real-life study
• Pills prevent HIV infection
• First pill approved to prevent HIV

African women who were testing a gel or a pill to protect them from the AIDS virus weren’t able to use either consistently enough to tell if they worked, researchers reported Monday.

The news is a disappointment to the field, especially since an earlier study suggested the gel could really lower the infection rate.

“The bottom line is the women were not using the products,” Jeanne Marrazzo of the University of Washington in Seattle told a news conference. And the women who were the least likely to use the pills or gel as directed were those most at risk – young women under 25, who weren’t married and may have had multiple sex partners.

The findings are “disappointing,” Marrazzo told a meeting of AIDS researchers in Atlanta called the Conference on Retroviruses and Opportunistic Infections.

Researchers have been trying for years to find good ways that women, especially, can use to protect themselves from the human immunodeficiency virus that causes AIDS. More than 60 percent of adults newly diagnosed with HIV in Africa -- where the epidemic is worst -- are women infected by husbands and other male sex partners.

Studies have shown that microbicide gels or creams can work -- at the last AIDS conference in Vienna in 2010, researchers reported on one that reduced a woman’s risk of infection by 39 percent. And other studies have shown that taking a daily AIDS drug in pill form can also protect people at high risk -- such as the spouses and partners of infected people. The trials have worked well in some countries, but not others. Experts fear inconsistent use may be one problem.

The trial reported Monday confirms these fears.

Marrazzo and colleagues tested three different approaches in more than 5,000 women in Uganda, South Africa and Zimbabwe. They tried two pills containing HIV medicines and a vaginal gel. After the study started in 2009, 312 of the 5,029 women became infected – an infection rate of 5.7 percent. That was almost double the rate the researchers had expected.

“The women who were most likely to take the drugs were women who were older than 25 and who were married,” Marrazzo said. They were probably the women at the lowest risk, but because so few women used the gel or took the pills as directed, the researchers couldn’t really tell anything about how well the drugs worked.

"No intervention is going to be effective if it's not used,” Dr.  Zvavahera Mike Chirenje of the University of Zimbabwe in Harare, who helped direct the study, said in a statement.

Researchers are looking for approaches that won’t require people to remember to take a pill or use a gel every single day. One team has begun a trial of a device called a vaginal ring impregnated with dapivirine, a drug used to treat people with HIV. Researchers will enroll 3,500 women in the two-year study to be conducted in Africa. Women could insert the ring and not think about it for as long as a month at a time.

Products that are long-acting, such as the dapivirine vaginal ring … and that women use for a month at a time, may be more suitable for this vulnerable population,” said Sharon Hillier of the University of Pittsburgh School of Medicine, who is helping to lead that trial.

The AIDS virus infects 34 million people globally and has killed 25 million more, according to the United Nations. Every year, more than 2 million more people are infected. There’s no vaccine and no cure, although cocktails of strong drugs can keep patients healthy, and low doses of certain drugs can help prevent infection.

Related news:

• Baby free of HIV, but is it a cure?
• The female faces of HIV
• How microbicides might work

A baby born infected with the AIDS virus who got immediate treatment now has no detectable virus in her blood – not quite a cure, but so close to one that it has doctors talking about the possibility.

Her case, presented to a meeting of AIDS researchers that started Sunday, will prompt questions about how early babies should be treated – and further illustrates the possibility that immediate treatment with HIV drugs might stop infection in its tracks and could even have an impact on the AIDS pandemic.

“What we have identified is what we think is the first well-documented case of a functional cure in a neonatal child,” Dr. Deborah Persaud of the Johns Hopkins Children’s Center, the virologist who led the study, told NBC News.

A functional cure, says Persaud, means the virus isn’t entirely gone, but it’s not doing any damage, either. Doctors think it was because they began therapy for the baby within 48 hours of being infected, she told a conference in Atlanta of HIV specialists.

The child, who lives in rural Mississippi, is now 2 1/2 and healthy. She was, like so many, born to a mother who didn’t know until right before she gave birth that she had the human immunodeficiency virus (HIV) that causes AIDS. Mom and baby both got a standard dose of HIV drugs right away – something that has been shown to prevent what’s known as mother-to-child transmission of the virus in newborns.

Johns Hopkins Medicine

Dr. Deborah Persaud of the Johns Hopkins Children's Center. She helped discover the case of a toddler who is close to being "cured" of HIV.

The baby was a little premature and so stayed in the hospital. Within 30 hours of birth she was re-tested and had clear evidence of HIV infection. Unusually, she then got a cocktail of three drugs at a dose normally reserved for more advanced cases.  It worked really well – pushing her virus down to what’s called undetectable levels. This is what doctors want with HIV, because if the virus can’t be found in the blood, then it can’t be spreading and damaging the immune system. HIV doesn’t kill directly – it kills patients by damaging their immune systems so bad they can’t fight off other infections.

The baby and her mom, who doctors aren't naming, got regular care and treatment by Dr. Hannah Gay at University of Mississippi Medical Center until she was 15 months old. Then, like so many children, she disappeared off the doctors’ radar screens. The mother brought her back briefly at 18 months but disappeared again but she missed at least eight months worth of drugs. When Gay caught up to her again, the baby was still well, despite having received no treatment. More remarkably, tests showed the virus had not come back.

“My first thought was, ‘oh my goodness. We have been treating an uninfected child,” Gay told NBC News. "But I checked the records which confirmed she was, in fact, infected.”

Dr. Katherine Luzuriaga of the University of Massachusetts Medical School, who also worked on the study, piled on with a battery of tests. Even a sensitive test called PCR, which can help find tiny bits of genetic material from a virus, couldn’t detect any evidence of HIV. This went far beyond the usual definition of "undetectable" in treating the AIDS virus - there really was no evidence the virus was there.

“What we did then was to get a group of collaborating laboratories together to apply ultra-sensitive testing  and say ‘can we detect any evidence of virus’,” Luzuriaga says. They did eventually find pieces of genetic material from the virus.

But Persaud has been unable to find any evidence of virus that can invade cells or replicate. “So the baby has remained off treatment. We are just watching and we will follow the baby and do additional testing.”

It’s not a true cure – what doctors call a “sterilizing” cure. There is still virus in the toddler’s body. But it’s not is a form that seems to be doing any damage. It doesn’t seem to be able to spread from one cell to another and it doesn’t seem to be damaging the child’s immune system.

About 34 million people globally are infected with HIV, the virus that causes AIDS; 25 million have died from it. While there’s no vaccine, cocktails of powerful antiviral drugs called antiretroviral therapy (ART) can keep the virus suppressed and keep patients healthy. No matter how long patients take ART, however, they are never cured. The virus lurks in the body and comes back if the drugs are stopped. Scientists want to flush out these so-called reservoirs and find a way to kill the virus for good.

“This has major implications for how we begin to think about treating children,” Persaud says. “Perhaps we can spare them a lifetime of treatment.”

But she adds, it’s one case.  “We need to figure out if this can be reproduced or replicated in other infants.”

Babies born to HIV-positive women are different from other HIV patients. Doctors know the precise moment that they are infected and can treat them right away. But usually they treat them with low doses of drugs for about six weeks and then wait to see if infection has really developed before they treat them again. If done right, this treatment around birth can prevent 95 percent of infections.

Up to now, only one person has been documented with a cure – the so-called Berlin patient, Timothy Brown, who was treated for leukemia with a bone marrow transplant that happened to come from a donor with a genetic mutation that makes immune cells resist HIV infection. The transplant replaced his own infected cells with healthy, AIDS-resistant cells. He is remains free of the virus more than five years later.

Dr. Dan Kuritzkes of Brigham and Women's Hospital and Harvard Medical School is treating two HIV other patients who, like Brown, got bone marrow transplants for leukemia or lymphoma. His team wants to see if they, too, can be cured. “They are doing fine,” he says – but continue taking HIV drugs to be safe.

But a third patient he was treating suffered a relapse of lymphoma and died. “It sort of underscores what these patients have been through,” he said. No one thinks a bone marrow transplant represents a real-life treatment for anyone with HIV, because it’s so hard on the body.

Kuritzkes said AIDS experts have wondered whether very early treatment of newborns could be in fact treating their infection rather than preventing it.

“It’s exciting because there are undoubtedly other children in this situation,” he said. His team is taking part in several studies looking at whether it is possible to eradicate the reservoirs of virus in adults that should have results within a year.

There are also patients called “elite controllers” who seem to stay well and suppress the virus without the need for drugs.

Luzuriaga says this toddler is not an elite controller. “You can detect HIV DNA in their cells. And you can culture virus from them,” she said. “We just think that this baby has much tighter control, much tighter control. This baby hasn’t rebounded off therapy.”

“Our next step is to find out if this is a highly unusual response to very early antiretroviral therapy or something we can actually replicate in other high-risk newborns,” says Persaud.

It might be that quick treatment stopped the virus from hiding out in the baby’s body, and allowed the drugs to do their work and stop the spread of the virus.

Ami Schmitz contributed to this story.

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