We don't know why, but there are some gradients of infection.

Our goal is not to completely eradicate the infection - that would be very difficult - but to produce a vaccine that will prevent not infection but disease. I think this is more possible.

It's easier to learn things for life by the age of 12 and not the age of 18. This is just my guess.

The idea of the live-virus vaccine is to produce in a continuous way some viral antigens.

It's clear that prevention will never be sufficient. That's why we need a vaccine that will be safe.

My proposal now is to test a vaccine first on people who have been infected, and if you show some efficacy at this level, you might be able to go further to study uninfected people in a population with a high rate of infection.

Since most of the transmission is sexual transmission, you have a regional or local response to the virus.