Antiviral condoms will help protect Australian Olympians from STIs - here's how

The science behind the condoms

The condoms help prevent infection through a combination of defences.

The first layer of protection is the physical barrier provided by the condom itself. An intact condom is effective against all bacteria and viruses, and only loses its protection when it breaks or develops a hole. But the condom is not itself antiviral.

The second layer of protection is the lubricant, called VivaGel, which is provided for use with the condoms. The condoms are only antiviral when used in combination with the lubricant.

The lubricant uses a special type of compound called a dendrimer. In this case, it is a sphere-shaped polymer, mostly made up of the amino acid lysine, that acts as a polyanion-based entry inhibitor. This means the active ingredient in the gel can bind to various viruses and stop them from attaching and getting into human cells. The dendrimer used in the VivaGel is called astodrimer sodium.

The gel was only approved by the Australian Therapeutic Goods Administration in 2014 and gained European approval in 2015. Several clinical trials are ongoing in the United States.

What does it protect against?

The manufacturer, Starpharma, claims the condoms with antiviral lubricant provide added protection against HIV, the cause of AIDS, and herpes simplex virus 2, the cause of genital herpes.

The VivaGel lubricant also potentially provides added protection against HPV which is a causative agent in the development of cervical cancer. While men who become infected by HPV can not develop cervical cancer, and may show no signs they are carrying the virus, they can act as a carrier and pass it to women.

As HPV is also a risk factor for anal cancer, the virus can also potentially be transferred to other men and women. The lubricant may help prevent infection in this way.

While the company has not conducted clinical trials on the Zika virus, the results of laboratory tests also show that it is possible that the condom and lubricant may also provide added protection against this infection.

Read more of The Conversation's Zika coverage here.

There are no treatments or vaccines against Zika, so protection against infection is important. While the virus is principally transmitted through the bites of infected mosquitoes, it is also possible Zika can be transmitted through sexual intercourse.

Of course, like any medical treatment there are potential risks. The side effects of the dendrimer in VivaGel have been reported to include irritation, vaginal pain, bleeding, burning, or itching when applied internally as a gel.

We want our Australian athletes to have a great time, both in and out of competition, and the provision of these condoms with antiviral lubricant seems a prudent move to help safeguard their health while they compete.

Nial Wheate, Senior Lecturer in Pharmaceutics, University of Sydney

This article was originally published on The Conversation. Read the original article.