Moving quickly to suppress the virus

Usually, these infants would get anti-viral drugs at preventative doses for six weeks to prevent infection, then start therapy if HIV is diagnosed.

Investigators say the Mississippi case may change that practice because it highlights the potential for cure with very early standard antiretroviral therapy (ART).

ART is a combination of at least three drugs used to suppress the virus and stop the progression of the disease.

But they do not kill the virus. Tests showed the virus in the Mississippi baby's blood continued to decrease and reached undetectable levels within 29 days of the initial treatment.

Dr. Deborah Persaud, a virologist with Johns Hopkins Children's Center, was lead author on the report.

The early treatment likely led to the infant's cure, she said.

"Prompt antiviral therapy in newborns that begins within days of exposure may help infants clear the virus and achieve long-term remission without lifelong treatment by preventing such viral hideouts from forming in the first place," Persaud says.

Persaud and Luzuriaga are part of a group of researchers working to explore and document possible pediatric HIV cure cases. The group was funded by a grant from amfAR, the Foundation for AIDS Research; and the National Institutes of Health.

Dr. Rowena Johnston, amfAR vice president and director of research, said it is "imperative that we learn more about a newborn's immune system, how it differs from an adults and what factors made it possible for the child to be cured."

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health, is enthusiastic about the findings.

"The best way to either eliminate the virus or allow the immune system to suppress residual virus is to treat someone as early as possible after infection so as not to allow a substantial reservoir of the virus to take hold," Fauci told CNN.

"At the same time, you prevent the immune system from being severely damaged by the continual replication of (the) virus for an extended period of time," he said. "The situation with a child born of an infected mother where most of the infections are transmitted to the newborn at or around the time of delivery provides an excellent opportunity to cure an infected baby, and this approach deserves further study."

"Berlin patient"

Researchers say the only other documented case of an HIV cure is that of Timothy Brown, the "Berlin patient." In 2007, Brown, an HIV-positive American living in Germany, was battling both leukemia and HIV when he underwent a bone marrow transplant that cured not only his cancer but his HIV as well.

In an interview last year, Brown told Dr. Sanjay Gupta, CNN's chief medical correspondent, he was still HIV-free.

"I've been tested everywhere possible," said Brown who now lives in San Francisco. "My blood's been tested by many, many agencies, I've had two colonoscopies to test to see if they could find HIV in my colon, and they haven't been able to find any."

But Brown's case is rare.

And, the procedure, which is extremely dangerous, won't work in most patients because the bone marrow he received had a special genetic mutation that made the stem cells in it naturally resistant to the virus.

Researchers tell CNN only 1% of Caucasians -- mostly Northern Europeans -- and no African-Americans or Asians have this particular mutation.