IARC 50th Anniversary Conference
Monitoring HPV vaccination program impact in Bhutan and Rwanda
Dr Gary Clifford - IARC, Lyon, France
Since about five years now Bhutan and Rwanda were the first countries, the first low and middle income countries, I should say, were the first to implement HPV vaccination on a nationwide scale. Now this is because the governments were quite public health orientated and so they rolled out these vaccination programmes. But obviously the evidence for the impact of these vaccination programmes, which are primarily on young girls prior to sexual activity, will not be seen on cancer for twenty years. These governments need a little bit of evidence that they are getting some sort of impact for their investment earlier and so we are there basically to try to show the impact of the vaccination on the prevalence of the virus itself, HPV, in sexually active girls.
What were your findings?
First of all I would say before we even get into talking about the impact on the virus itself, what was very clear is that the success in terms of the coverage of the target population that is associated with a school-based delivery approach. So working with schools and targeting children, young girls, the actual target age group was twelve years old but they actually had an initial catch-up campaign up to eighteen years old, but doing that with the school was associated in Bhutan with an almost ubiquitous uptake of the vaccine in the target age group. Following this initial campaign they switched the delivery approach to something that was more routine for vaccinations which is doing it through basic health centres and they noticed after a few years that the coverage of the target population of twelve year olds was dropping. We were able to work with them to produce this data and publish it which would be a good model for other countries, but they themselves already realised that this was not good enough. So since 2014 they have switched their vaccination approach back to a school-based delivery; even though it costs a little bit more and it is a little bit more arduous, they clearly see the benefit.
Where was this implemented?
That’s happened in Bhutan, Rwanda have kept a purely school-based approach but they too noticed that when they tried to capture the girls that were outside school that the success in getting the coverage of vaccination in those girls was also much lower.
What are the dos and don’ts regarding how you conduct this programme?
What I’ve been talking now about is really just the coverage of the vaccination, just how many girls were getting access which was almost the first step. What’s very important in Rwanda is that a large proportion of the population are HIV positive and that’s something that we saw also in our study. So basically what we went on to do was to, in a sample of women, was actually to try and understand what was the prevalence of the virus in the young women in the populations before the vaccination programme and then we will be repeating this work in the following years to really show the impact of this high coverage, because they did get high coverage, on the actual virus itself.
How is it progressing?
It does look as though it’s going well and the real sort of thing that we piloted for the first time, which has given us the first results actually earlier than we had expected, is to use urine sampling to get an idea of the prevalence of the virus in the young age population. Because, of course, you have to wait to see the impact of the vaccination in these young girls as they grow up and young girls don’t like to go for gynaecological exams. It’s true, you can understand, they don’t need it so the people that you tend to be able to study are an opportunistic biased group. But urine testing was something that we found could be very feasible, acceptable to a wide range of pretty young girls, between seventeen and nineteen, and is able to get a representative sample. In that group the question is have we seen anything? Yes, we already see in that age group of girls an impact of the vaccinated girls have lower HPV prevalence against the cervical cancer causing types than the girls that did not have the chance to get vaccinated.
If there is co-infection with HIV is there still a bonus from the HPV vaccine?
Well we haven’t yet been able to address that; evidence would suggest yes, evidence would suggest that perhaps they have even more to gain because they are more at risk of developing cervical cancer. But this certainly, as the years go on and these girls grow up and we repeat our surveys in older groups of women, and this certainly an aspect that we want to know more about. We’ve basically set the baseline for future comparisons.
What are the implications for doctors?
The beauty of vaccination is there’s not much to do after the girls have had their vaccine. Perhaps the evidence is that we don’t need to worry because this group of girls will be protected. Perhaps these first two countries will serve as sentinel settings where other countries, low and middle income countries who will be supported through subsidised programmes over the next years to get vaccines into their own countries, can maybe rely on this evidence to show that, yes, these vaccines do work also in the kinds of settings that they can associate themselves with and not only in places like the UK and Australia which produce very good data but are very little similar to their settings.
What is your take-home message?
If you’re going to invest in an HPV vaccination programme then monitoring the programme is not essential. You may want to rely on data being generated by other long standing collaborations through scientists but if you want to do it then probably the quickest way to get some evidence to support your investment in the short term is to perhaps do some testing in urine samples among young girls. But make sure you get your comparison group of unvaccinated girls quite quickly.
