An announcement has been made by San Francisco’s largest private health insurer that its 657 clients who have been receiving a daily pill for over two years are not attacked by HIV, showing that the drug could assist in preventing HIV infection in real life. US researcher Chris Beyrer, co-chair of the International AIDS Society (IAS) science conference in Vacouver, said, "The data is overwhelming... it works when it’s taken. Our results support strongly the scale-up of PrEP."

The research team also found that the drug was well taken by most of the patients, with minimal side effects. Adverse reactions included headache and weight loss.

The result was opposite to predictions by some critics. They said that pre-exposure prophylaxis, or PrEP, would make people use condom less often which could lead to more HIV infections.

It has been found in a study published in Clinical Infectious Diseases that the San Franciscans on PrEP used fewer condoms, and were attacked by a number of other venereal diseases.

However, no one was infected with HIV. Most of the people on PrEP were gay men. The majority of other potentially dangerous sexual infections could be treated with antibiotics. But when it comes to HIV, it cannot be treated. However, it is possible to control it with antiretroviral drugs that could be taken for life.

Adam Zeboski takes a daily pill, Truvada, and reported that it was helpful in preventing infection with the virus that leads to AIDS. Damon Jacobs, a New York psychotherapist, started taking Truvada after breakup. According to him, he was using condom less often.

Michael Weinstein, president of the AIDS Healthcare Foundation, has spoken a lot against Truvada. Considering a 99% claim of effectiveness of the drug may make some Truvada users think about almost zero HIV risk, whereas they should thinking about very low risk.

In a study conducted in Brazil between 2014 and 2015, 509 men participated and were given daily PrEP. The medicine was well-received by recipients, “though more education is needed,” said Beatriz Grinsztejn, Instituto Pesq Clinica Evandro Chagas.