IDWeek presenter highlights global implications of HIV treatment resistance in Philippines

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Science Speaks spent Oct. 4-8 in San Diego, covering IDWeek, a conference of the Infectious Diseases Society of America, the HIV Medicine Association, the Society for Healthcare Epidemiology of America, and the Pediatric Infectious Diseases Society

Oct. 7, 2017

SAN DIEGO –  Dr. Edsel Salvaña has two posters in the exhibit hall here, each one carrying terrible news from the Philippines, that, if you pause to look at the one he stands in front of, he will cheerfully and concisely explain, has frightening implications well beyond his country. In fact, with findings showing an explosion of drug-resistant HIV in the Philippines following the spread of a new subtype of the virus there, the trend his posters are showing in the Philippines has worldwide ramifications.

The implications are all the more daunting because the transmitted strain is resistant to tenofovir, the antiretroviral drug that is used for Pre-Exposure Prophylactic protection against HIV — or PrEP.

He smiles easily, when he explains this, and has a ready laugh, when he sees the people he is talking to get it. “It’s all I can do,” he explains.

Not exactly. Dr. Salvaña is now in his second decade of collecting and sharing data in increasingly accessible ways most recently at a September Global TED Conference in Arusha, that he recalls with some satisfaction, left audience members aghast.

The findings from the Philippines represent not only a larger scale disaster in the making, he explains, but one that had strong elements of predictability well before he stumbled on an epidemic of HIV treatment failure in the course of gathering data to guide HIV responses in his country.

That standard treatment might fail large numbers of patients receiving it was somewhat foreseeable, he explains, because while only about 12 percent of people with HIV on earth are infected with HIV subtype B   – predominately in Europe and North America — about 90 percent of research leading to treatment guidelines endorsed by the World Health Organization centers around that subtype.

“What works for subtype B,” he notes, “might not work for everyone else.”

Dr. Edsel Salvana explains rising ART resistance rates in the Philippines.

That’s what happened in the Philippines, where Dr. Salvaña returned from his infectious disease fellowship in the early 2000s to discover a relatively late, burgeoning, and largely ignored epidemic of HIV spreading from one vulnerable population to another, and demanding immediate medical and education interventions. In the course of gathering data to indicate the scope of the challenges the country faced he explored surveillance data on patients in treatment whose virus was worsening rather than improving. Missed doses explained that treatment failure in only about half of the patients he found. Looking for reasons for the failure of treatment among the rest he found high rates of transmitted resistance to the antiretroviral medicine most commonly used as first line treatment. And he found a reason for that —  in recent years the subtype of virus spreading in the Philippines had shifted from type B to a subtype AE – a subtype common in Thailand but new to his country. Having traveled to the Philippines in recent years, Dr. Salvaña noted, it had since exploded.

The subtype is also emerging in China, Australia, and parts of the United States, he added. “So it’s not a stretch if it goes from B to AE there, it will explode as well.”

“If you think about it, HIV mutates 1,000 times faster than bacteria.” He says. (He checks this later, and says that was a gross underestimation — HIV mutates a million times faster).  “In fact, in the same person, you can have genetic differences between the infecting strain, and the offspring viruses of five percent.” Dr. Salvana explains. “That’s more than the genetic difference between humans and great apes.”

The TED talk made him better at getting his message across memorably and quickly, he says, “I had to get it across in four minutes.”

It worked well, he believes.”At the end of my talk, everyone had a horrified look on their faces!” he says. “They almost forgot to clap!”

Dr. Edsel Salvana presents his data in a September TED talkin Arusha. Photo: Bret Hartman / TED

 

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