Neither dispassionate information nor scare stories are the answer: we need public engagement on health interventions, argues Priya Shetty.
Scientists have long sought the best way to counteract misinformation about health. But too often, indecision over how best to bring the public on-side has paralysed action. Should health experts fight fire with fire for example, and counter scare stories about a new health intervention with equally disturbing scenarios of not adopting it? Or should they provide people with dispassionate information and hope they make the right decision?
The answer is neither. Global health experts are realising there can be no substitute for engaging with the public, and some new collaborations are offering a model of the way forward.
History of mistrust
The public has often mistrusted health programmes like vaccination. Suspicion over childhood immunisations against diseases like measles, for example, has recently lowered immunisation rates in developed countries, where the disease is starting to re-emerge. 
Now, scientists are starting to roll out new vaccines for diseases specific to developing countries: we are on the brink of an effective malaria vaccine; there has been huge progress towards an HIV vaccine; the HPV vaccine (against cervical cancer) is being rolled out worldwide; and there is a renewed push to fund vaccination to finally eradicate polio.
For these technologies to deliver their promise, it is crucial to counter mistrust in developing nations. Already there has been controversy, not entirely settled, over the HPV vaccine in India. And in 2003, a polio campaign in Nigeria had to be abandoned after some Muslim clerics allegedly spread rumours that the injections were infected with HIV in a Western conspiracy.
Yet while religious leaders can spread hugely counterproductive messages about health — like the Vatican's continued opposition to condoms despite their role in stopping HIV transmission — health organisations are now realising they can also be important allies.
For instance in Pakistan, where polio is still endemic, UNICEF's work with the country's National Research and Development Foundation (NRDF) has rallied more than 5000 religious leaders to denounce vaccine myths and encourage people to be immunised. 
Integral, not an add-on
But ensuring public support will require more than this. Communicating and engaging with people must be woven into the fabric of health strategies, rather than added on as an afterthought.
One network taking communication very seriously is the Decade of Vaccines collaboration, a high-level partnership between the WHO, UNICEF, the Gates Foundation, the GAVI Alliance and others.
Public and political support is one of its four core programmes (the other three are on research and development, delivery, and global access). It includes a focus on "the moral case for vaccination, vaccine counterpoint cases and global vaccination sentiment."
The communication Working Group of the collaboration is committing to, among other things, "advising other Working Groups by applying advocacy considerations to all technical products". This is perhaps one of the first times that communication has been taken as seriously as research and delivery for a health intervention.
Right now, the collaboration is consulting a diverse group of stakeholders to develop its global action plan, which aims to ensure that public sentiment is held in high regard.
Doubt increasingly likely
Arguably, this engagement effort has come later than it should have — the need for it is urgent. It will be invaluable for designing future vaccine roll-outs. And this approach, which integrates communication into core strategies, needs to be used in many other areas of health research too.
Biomedical techniques are now so complex and use such high-level technology that public mistrust or doubt is increasingly likely.
Active engagement with the public can support proper debate on the risks and benefits of new technologies. The introduction of GM crops is one such contentious issue, dividing scientists and the public all over the world. For example in 2010 safety concerns delayed the introduction of GM brinjal into India.
Another example is nanotechnology, which could revolutionise healthcare. Yet public opinion on potential risks has not yet been explored in developing countries. Failing to engage the public can even endanger scientists; earlier this year, bomb attacks on Mexican scientists were organised by a radical anti-nanotechnology group, who say they are planning further attacks.
Essential for success
The best technologies will fail if no one uses them. Ensuring that people's voices are heard, and giving them a stake in decisions about new technologies that affect their health, will be key.
Communicating the risks and benefits of health interventions is no longer enough. As technologies continue to advance, people are likely to become more critical to the success or failure of public health programmes. If health experts want their interventions to work effectively, they have got to engage with the public.
Journalist Priya Shetty specialises in developing world issues including health, climate change and human rights. She writes a blog, Science Safari, on these issues. She has worked as an editor at New Scientist, The Lancet and SciDev.Net.
 Measles resurgence tied to parents' vaccine fears (NPR, 2010)
 Muslim scholars fight to dispel polio vaccination myths in Pakistan (Guardian, 2011)