BY DANIEL CHANG AND NORA GÁMEZ TORRESDCHANG@MIAMIHERALD.COM
A strain of HIV that progresses to full-blown AIDS within three years if left untreated has become “epidemic” among newly-infected patients in Cuba who reported having unprotected sex with multiple partners, according to a study published this week by international researchers working with patients and doctors on the Caribbean island nation.
The strain of HIV — a combination of three subtypes of the virus — progresses so fast, researchers at Belgium’s Catholic University of Leuven reported they worry that patients infected with the mutated virus may not seek antiretroviral therapy until it’s too late.
Findings published this week in the medical journal EBioMedicine raise concerns among South Florida AIDS researchers, who worry that mutated HIV viruses are more difficult to diagnose, might eventually become resistant to therapy and could challenge efforts to develop a vaccine.
But researchers also questioned the researchers’ methodology and the scientific community’s ability to replicate the findings with just 95 patients in the study.
Hector Bolivar, a physician and infectious disease specialist with the University of Miami Miller School of Medicine, said the HIV research community has long known about the virus’ capacity to mutate and create new versions.
More than 60 strains of HIV type 1 exist in the world because of mutations. But this one is in South Florida’s back yard.
“The only thing now,” he said, “is that in Cuba, it is associated with rapid progression [of the disease]. It’s something that hasn’t been seen before that clearly.”
Professor Anne-Mieke Vandamme of the Catholic University of Leuven and a team of researchers reported that they traveled to Cuba after clinicians on the island reported an increasing number of HIV infections that rapidly progressed to AIDS, usually within three years.
To conduct the study, Vandamme and her team recruited patients at the Institute for Tropical Medicine Pedro Kouri in Havana who had tested negative for HIV less than three years before diagnosis and who had not received therapy.
Researchers reported studying the blood of 73 patients recently infected with HIV — 52 who had been diagnosed with AIDS, and 21 without AIDS — and then comparing the results with blood samples from 22 patients who had progressed to AIDS after living with HIV for more than three years.
None of the patients had received therapy for the virus. But all of the patients infected with the mutated strain of HIV, known as a recombinant, developed AIDS within three years. On average, persons infected with HIV develop AIDS in six to 10 years.
Researchers also reported that persons engaging in unprotected sex with multiple partners increased their risk of contracting multiple strains of HIV that, once inside the host, could mutate or recombine into a new strain.
The study’s findings, Bolivar said, raise a particular concern for South Florida.
“We knew that sooner or later we were going to face this locally,’’ he said. “Cuba is local for Miami. We may see similar situations here in Miami in the future, and that’s something I’m concerned about.”
He also has misgivings about the way the study was conducted, he said, and whether other scientists will be able to reach similar conclusions.
For instance, he said, the sample size — 95 patients — is not large enough to extrapolate significant findings for the thousands of people in Cuba living with HIV.
It was also unclear precisely when the study’s subjects contracted the virus, Bolivar said, and he questioned the ethics of allowing patients with HIV to develop AIDS without treatment.
“It’s very difficult for us in the United States or Europe or many places where there are treatments [for HIV] to replicate these findings in the long term because it’s unethical to wait until someone progresses until they can no longer benefit from treatment,’’ he said.