Researchers have concluded that when it comes to communicating the science behind contentious health issues, the message is we need to show we care before we share. Even if it means weathering a storm of outrage.

Whether it's promoting the merits of vaccination, or adding fluorine to our public water supply, it can be hard for experts to compete with emotional outbursts from an anxious community, making fact-based conversations a virtual impossibility.

An investigation of existing research by the Sax Institute in Australia highlights the challenges faced by public health officials in a 'post-truth' world filled with diverse opinions and misinformation.

It's often assumed that emotions from a fearful public can prevent effective health policies from working, and that makes it rather tempting to find ways to silence dissent.

"But our research suggests that trying to shut off this criticism can make things worse, particularly as it's now almost impossible to effectively control the flow of information on social media," says one of the team, Claire Hooker.

It's commonly understood that countering bad information with good information is also counter-productive, thanks to a psychological quirk called the backfire effect.

As a social species, we tend to only accept information once we've identified its source as 'one of us', which often drives to us to prioritise ideas that already confirm our beliefs over those that contradict it.

In fact, hearing critical information from somebody we don't trust can cause us to double down on our views, making it nearly impossible to change deeply entrenched opinions with facts alone.

Where public concern over a controversial health measure is considered high in spite of the actual risks being relatively low, the researchers suggest starting with empathy before wading in with the science.

"Research shows that when people are emotional about an issue they have more difficulty hearing and processing information, and are more likely to pay attention to negative information," says Hooker.

"That's why the golden rule of successful risk communication is that people need to hear that you care before they will care about what they hear."

As an example, the study suggests acknowledging the challenges involved with raising a child who has autism before refuting claims of links between the condition and vaccines.

The researchers analysed previous studies on best practice in public health communication, exploring factors which were associated with exaggerating the impression of high risk.

Their report, published in full in Public Health Research & Practice, discusses a range of processes and actions that determine whether a communication strategy will succeed or fail.

When met with a need to choose between building trust and tolerating overreaction, the researchers advise working on that rapport.

The report also advises being transparent about uncertainty in policy, stating clearly what is and isn't known about a measure's outcomes, and argues that actions themselves make far clearer messages than words.

Lastly, the study makes a case for public health officials speaking directly to the community to be strategic with the use of local and social media, rather than going through representatives or spokespersons using the traditional channels.

"This way local communities know that authorities have integrity, are competent and can be trusted – the key to reassuring people and reducing outrage," says Hooker.

It can often go against our better instincts to find ways to identify with people we disagree with, especially when their views are thought to put our community in danger.

But if we're serious about encouraging the community to support evidence based health practices, we need to look to the evidence on how best to communicate in the first place.

This research was published in Public Health Research & Practice.