As the HepHIV 2014 Conference in Barcelona continues, guest blogger Professor Jeffrey Lazarus tells us about the challenges we face to combat hepatitis in Europe.

When is it important to gather more evidence to inform the response to a major public health problem, and when must we act on the limited available evidence in order to save as many lives as possible? As I worked with my colleague Kevin Fenton to prepare a supplement published by BMC Infectious Diseases on viral hepatitis and drug use in Europe, I found myself reflecting often on this question.

It weighed on my mind in part because of the scale of the problem: the World Health Organization European region has an estimated 15 million people living with the hepatitis C virus (HCV), and two million of these people are thought to be current injecting drug users. The practice of sharing injecting drug equipment is widely recognised to be one of the key drivers of Europe’s hepatitis C epidemic today.

There is a need for swift action to fill a policy and programmatic void in many European countries regarding viral hepatitis prevention and treatment services for people who inject drugs. Growing recognition of this situation has helped to catalyse widespread interest in the first European Conference on Hepatitis C and Drug Use, slated for 23-24 October 2014 in Berlin.

We anticipate that many of those people who attend or follow the conference will find themselves grappling with a common challenge in its aftermath: how to move forward, whether on HCV prevention, treatment, surveillance, advocacy or other fronts, when there are so many gaps in the body of evidence that should be guiding us.

Case in point: the review article that I co-authored for this supplement. The article examined HCV treatment uptake levels among those who inject drugs in Europe. Key factors such as drug use, eligibility for HCV treatment, and criteria for when treatment should be initiated were conceptualised in such different ways from one study to another, that the review exercise left us reluctant to make any sweeping pronouncements about the extent to which drug users with hepatitis C are accessing treatment.

For studies reporting on treatment uptake levels among current injecting drug users – a critical issue from the standpoints of both disease control and human rights – only one of the 25 studies included in our review provided this information. But if someone were to ask me how many people who inject drugs with hepatitis C in the WHO European region are accessing treatment, I would emphatically respond, “Not nearly enough. And we need to do something about this – now.”

In other words, wrinkles will need to be ironed out of the evidence base before we can confidently put forth a HCV treatment uptake level for drug users that seems relatively precise. But do we really need a number in order to intensify advocacy efforts on behalf of those who need treatment?

Whether the real proportion is 30%, or more, surely almost everyone who works in this field would agree that making HCV treatment more accessible to those who inject drugs is a key advocacy and public health goal.

Unfortunately our current knowledge about many aspects of the health issues facing people who inject drugs is limited in ways that threaten to undermine the development of a cohesive European-wide response to the HCV epidemic in this population.

How, then, should decision-makers in this arena determine whether or not to move forward with strategies only weakly supported by the available evidence? There are no easy formulaic answers to such a context-specific question. But what I have learned from co-editing the supplement on viral hepatitis and drug use in Europe is that it is essential to involve the voices of diverse constituencies in this process.

I already would have taken that stance on principle; what strikes me now, after working closely with many of the supplement authors over a period of a year, is just how much wisdom and experience the community has to share.

I use the word “community” broadly in this instance, not to refer only to community-based organisations or civil society actors, but rather to the entire community of people who are increasingly drawn together by their shared outrage about societal neglect of people who inject drugs.

This community includes researchers, policy-makers, advocates, activists, programme implementers, and those PWID who are reaching out to all of the rest of us in an urgent attempt to make their needs better understood.

Several impressive examples of this community’s insights, drawn from both empirical research and lived experience, can be found in the aforementioned supplement. I greatly look forward to being further wowed when I attend the Berlin European HCV Initiative conference on 23-24 October 2014.

Professor Jeffrey V. Lazarus is the Secretariat Director of Health Systems Global and a Senior Researcher at CHIP, the Centre for Health and Infectious Diseases Research and a WHO Collaborating Centre, at Rigshospitalet, the University of Copenhagen.