A new surveillance tool might help immunize communities against vaccine scares, researchers reported.
An international pilot project has demonstrated that it's possible to trawl through the Internet and quickly identify places where public fear about vaccines is on the rise, according to Heidi Larson, PhD, of the London School of Hygiene and Tropical Medicine in England, and colleagues.
Larson and colleagues adapted the HealthMap automated data collection system -- usually used to track disease outbreaks -- so that it could monitor online reports about vaccines.
The system "allows systematic monitoring and assessment of media reports for vaccine sentiment, with the aim of detecting concerns as they emerge and evolve in real time," Larson and colleagues wrote online in The Lancet Infectious Diseases.
The issue is important, they noted, because vaccine scares can have serious consequences.
"The Internet has speeded up the global spread of unchecked rumors and misinformation about vaccines and can seriously undermine public confidence, leading to low rates of vaccine uptake and even disease outbreaks," Larson said in a statement.
A case in point, the authors wrote, is the 2003-2004 boycott of polio vaccination in Nigeria, which stalled the polio eradication program, cost millions, and led to the re-introduction of the disease in 20 countries that had been free of it.
In many such cases, they argued, "early signs of concern have often been available well before their most serious effects occurred, but were not acted on, largely because the potential results were not expected."
To help fill that gap, the researchers adapted the HealthMap system to search for any online mentions of human vaccines or vaccination campaigns or programs.
Over a year, from May 1, 2011, to April 30, 2012, the system found 10,380 such reports from 144 countries.
Of those, 31% were negative -- fears of adverse events, for instance, or distrust of the vaccine industry's motives -- and the rest were either positive or neutral.
Of the 3,209 negative reports, 24% were associated with impacts on vaccine programs and disease outbreaks, 21% concerned beliefs, awareness, and perceptions, 16% discussed vaccine safety, and 16% were associated with vaccine delivery programs.
As might be expected, the positive and negative reports tended to accentuate different things, the researchers noted.
Some 33% of positive reports were about vaccine development and introduction, compared with just 3% of negative reports. In contrast, 21% of negative reports were about beliefs, awareness, and perceptions, compared with 3% of positive reports.
The researchers cautioned that the system has not been running long enough to demonstrate "long-term predictive value," but added it will let observers characterize, in real time, vaccine opinions by "topic, negative or positive content, location, time, and risk level."
Health authorities can't afford to wait and see if they hope to develop successful vaccination programs, according to Natasha Sarah Crowcroft, MD, of Public Health Ontario and Kwame Julius McKenzie, MD, of the Centre for Addictions and Mental Health, both in Toronto.
"Public health systems need to move beyond passive responses to vaccine safety events towards active preparedness," they argued in an accompanying commentary.
They added that researchers need to understand how to make communities "resilient to bad science and interest-driven scare stories."
Crowcroft and McKenzie noted that speed is often important in plans to eradicate diseases. But, they concluded, "moving quickly enough will only be possible by first building strong public belief and confidence in immunization."
The study had support from the Bill and Melinda Gates Foundation. Larson and most other authors did not report any conflicts of interest. One author holds equity in a company formed to commercialize HealthMap data.
The comment authors said they had no conflicts.
- Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner
Lancet Infectious DiseasesSource Reference: Larson HJ, et al "Measuring vaccine confidence: analysis of data obtained by a media surveillance system used to analyse public concerns about vaccines" Lancet Infect Dis 2013: DOI: 10.1016/S1473-3099(13)70108-7.
Lancet Infectious DiseasesSource Reference: Crowcroft NS, McKenzie KJ "Inoculating communities against vaccine scare stories" Lancet Infect Dis 2013; DOI: 10.1016/S1473-3099(13)70131-2.