Dr. Derval Igoe:

The first thing to highlight is that these are estimates of the numbers we believe would benefit from vaccination. We used available data we have in the system to get our estimate. We used two different methods, both of which came up with a similar number. The first method was looking at the current numbers of people who are on the medicine PrEP to prevent HIV infection. We did not just take that number; we also looked at a potentially unmet need, which would include people who are waiting to get on that programme. We identified 4,000 people who are on PrEP and an additional 30% who may have an unmet need, which gave us 5,120 people. As well as that, we looked at people living with HIV who are gay, bisexual or men who have sex with men, gbMSM. Based on some information we have on behavioural surveillance, involving self-reported bacterial infection in the previous 12 months, which was available from an Internet-based survey we were involved in, we identified another 28% who reported such an infection. However, we know from Internet-based surveys that one may get an overestimate of the situation, so we halved that number. From that estimate, we came up with a number between 5,610 and 6,100, depending on whether or not we halved the number reporting bacterial infection via the Internet survey.