Experts say they’re concerned an HIV strain in the Philippines that is resistant to common treatments could make its way to the United States.

Researchers from the Philippines warn that a new drug-resistant subtype of HIV could worsen the epidemic in that country as well as have serious implications worldwide.

Dr. Edsel Salvaña, director of the Institute of Molecular Biology and Biotechnology at the National Institutes of Health at the University of the Philippines, discussed the aggressive new subtype of HIV in an interview with the German media outlet DW.

Salvaña said the AE subtype in the Philippines is a more aggressive form of the virus.

“Those infected by the HIV subtype AE are younger, sicker patients who are more resistant to antiretroviral (ARV) drugs,” he said. “We are also seeing a faster progression to AIDS under subtype AE.”

According to Dr. Sharon Nachman, division chief of pediatric infectious diseases and a professor of pediatrics at Stony Brook Medicine in New York, researchers in the United States are already facing the challenge of drug-resistant HIV.

“We are getting around it somewhat by using ARV drugs and combination antiretroviral therapy (cART),” she told Healthline. “We’re also using drugs much tougher for HIV to beat by mutating. Finally, by working hard to prevent new infections, there will be fewer opportunities for drug resistance to develop.”

The World Health Organization (WHO) warns that drug-resistant HIV is on the rise.

According to the WHO HIV drug resistance report in 2017, many African, Asian, and Latin American nations reported that more than 10 percent of patients starting antiretroviral therapy (ART) had a type of HIV that was resistant to the most commonly used HIV medicines.

The report includes Cuba, Guatemala, Nicaragua, Russia, and the Philippines among the countries where drug-resistant HIV is becoming a serious health concern.

Nachman says it’s impossible to prevent particular diseases from entering the United States.

“Diseases can all travel. There is no way to prevent an infection from getting on a plane, boat, or car,” she said. “The best approach is to consider where the infected person has come from, carefully pick a regimen to treat that disease, and then check if that regimen is working.”

Salvaña told Healthline the best approach is education.

“Learn more about HIV subtypes not commonly seen in the U.S. and their behavior,” he said. “HIV subtypes are so genetically distant from each other that we might as well be talking about a different species of virus per subtype. Knowing which drugs are best for different subtypes, and doing proper and routine surveillance to understand different HIV subtypes will be incredibly helpful in planning for the next wave of drug-resistant viruses.”

Pharmaceutical manufacturers are responding to the opioid epidemic in the United States by developing abuse-deterrent formulations.

But, a 2015 study published in The Journal of Infectious Diseases concluded that the trend of crush-resistant pills created an explosion of needle use that increased HIV infections from needle sharing between addicts.

Salvaña says that needle sharing can create drug-resistant strains because “HIV subtypes can mix and the mixed HIV strains will combine with other subtypes as well.”

Pre-exposure prophylaxis, also called PrEP, is when people with known risk factors for HIV take certain drugs to lower the odds of getting infected with the virus that causes AIDS.

According to a 2015 study, although rare, PrEP can result in treatment resistant mutations of HIV.

There are currently two documented instances of PrEP failure in patients who kept strictly to the drug regime. One was in New York City and the another was in Toronto.

Each of the strains of HIV they contracted were resistant to both medications in Truvada, the standard PrEP drug.

Salvaña said that PrEP can create drug-resistant HIV “if you give it to someone who was recently infected with HIV and is not aware of it yet.”

“The virus becomes resistant to the two drugs in PrEP because conventional HIV treatment uses three drugs,” he explained. “PrEP is still effective, but needs to be used properly with medical supervision.”

“This study and others have shown that someone who strictly follows treatment guidelines is at low risk for developing a resistant HIV infection while on PrEP,” said Dr. Stephen Parodi, chair of the board for the Council of Accountable Physician Practices (CAPP) and associate executive director of The Permanente Medical Group.

“The most important takeaway,” he added, “is that the best way to do PrEP is for a patient to take the medication regularly, not miss doses, and to regularly get tested so any new HIV infection is quickly detected to avoid resistance.”

Salvaña warns that, “As HIV becomes more drug-resistant, we will start seeing more PrEP failures. The major driver of HIV drug resistance is poor compliance with medications, also known as acquired drug resistance. But once someone who is on treatment becomes drug resistant, he/she can transmit the drug-resistant virus to other partners.”

Parodi said the best ways to reduce the risk of drug-resistant HIV is compliance.

“Support systems that help a patient’s ability to take their medications,” he said. “This includes housing, transportation, food insecurity, and financial ability to fill the prescriptions. We should also use the simplest drugs possible. There are now medicines with less side effects and that require only one pill per day.”

Parodi also believes that, “It’s critical to ensure that medication is taken, lab tests are frequently monitored, and newly HIV-positive people are tested for resistance to make sure that the regimen they’re prescribed is the most effective.”