A new study suggested that resistance to a leading HIV drug is common across the world and could mean problem for treating and preventing the virus that leads to AIDS.

Researchers have reported in The Lancet Infectious Diseases that in some parts of the world, over 50% of people, who have been suffering uncontrolled HIV despite treatment have turned out to suffer from a kind of the virus that is resistant to the drug tenofovir,.

Senior author Dr. Ravi Gupta, of University College London said that the latest study has suggested that treatment and monitoring of HIV patients worldwide reuire improvement, and surveillance should also be increased.

Tenofovir is the drug selected when it comes to the treatment and prevention of human immunodeficiency virus (HIV). It can also be used for the treatment of hepatitis B.

Study author Dr. Robert Shafer, of Stanford University in California, said that if an individual develop resistance to that, it’s a huge loss.

While talking Reuters, Gupta said, “The availability of second-line drugs is increasing, but they're quite a bit more expensive and have more side effects associated with them”.

He said that people get HIV resistance to tenofovir in two ways. Either they don't consume the drug as intended due to which the virus mutates, or they have got infected from a person suffering from a resistant form of the virus.

To conduct the study, the researchers used data from 1,926 people across 36 nations, who continued to have uncontrolled HIV despite simultaneous treatment with a range of drugs, including tenofovir.

The amount of people suffering from tenofovir-resistant HIV ranged from 20% in Europe to more than 50% in sub-Saharan Africa.

Though the study can’t suggest the reason behind tenofovir-resistant HIV, the researchers have discovered that the health of the immune system in the beginning of treatment, and the other drugs in the treatment regimen, are associated with resistance risk.