Vaccines: New Surveillance Tool Detects Public Concerns

Laurie Barclay, MD

May 12, 2013

A new global media surveillance tool detects and monitors public concerns about vaccines in real time, according to a study published online May 13 in the Lancet Infectious Diseases. By allowing public health officials to respond faster and more effectively to a loss of public confidence in vaccines, the new tool could help reduce vaccination refusals and disease outbreaks.

"Recent measles outbreaks in the UK, stemming from children not-vaccinated due to fears prompted by now-discredited research over a decade ago, is one example of the long-term consequences of broken public trust in vaccines," lead author Heidi J. Larson, PhD, from the London School of Hygiene and Tropical Medicine, United Kingdom, said in a news release.

"The Internet has speeded up the global spread of unchecked rumours and misinformation about vaccines and can seriously undermine public confidence, leading to low rates of vaccine uptake and even disease outbreaks," Dr. Larson adds.

After preliminary research by the Vaccine Confidence Project, the investigators used existing surveillance systems to develop a new application for identifying and quantifying early signs of public concerns regarding vaccines. They adapted the HealthMap automated data collection system to monitor online media articles, blogs, and government reports about human vaccines, vaccination programs, and vaccine-preventable diseases.

The investigators analyzed the included reports for content, categorized them, determined their overall positive or negative sentiment toward vaccine, and prioritized them based on their seriousness, time of reported event, and potential to disrupt vaccine uptake.

After the investigators refined the search terms and processes, they used descriptive statistics to analyze data from 10,380 reports (from 144 countries) obtained between May 1, 2011, and April 30, 2012. Content was positive or neutral in 7171 reports (69%) and negative in 3209 (31%).

Among the negative reports, 1977 (24%) dealt with effects on vaccine programs and disease outbreaks; 1726 (21%) dealt with beliefs, awareness, and perceptions; 1371 (16%) dealt with vaccine safety; and 1336 (16%) dealt with vaccine delivery programs. The investigators separated data by country and vaccine type and were able to monitor developing events in specific regions with high levels of vaccine concerns.

Tailored Engagement Strategies

"Real-time monitoring and analysis of vaccine concerns could help governments and public health officials locally, nationally, and globally understand where they should focus their attention and resources when a concern arises, and where specific vaccines might need more tailored engagement strategies," Dr. Larson said in the news release.

Limitations of this study, which the investigators are now attempting to address, include the use of only English search terms to collect the initial data and a lack of automation in data collection and classification.

In an accompanying comment, Natasha Crowcroft, PhD, MD, chief of infectious diseases at Public Health Ontario in Toronto, Canada, and Kwame Julius McKenzie, MD, from the University of Toronto, stress the importance of building strong public belief and confidence in vaccination.

"Researchers need to discover how to make communities resilient to bad science and interest-driven scare stories to change public ideas and norms and to promote belief in vaccines," Dr. Crowcroft and Dr. McKenzie write. "However, beliefs are hard to change, and correct information might paradoxically entrench existing negative attitudes and undermine positive ones. Pre-emptive action in childhood to promote immunisation might prime the minds of future parents, health-care providers, journalists, and politicians with a positive attitude towards immunisation."

The Bill & Melinda Gates Foundation funded this study. One representative from this foundation is a member of the project's international advisory group, which provided feedback over the course of the research, but the research team had sole responsibility for all decisions about the conduct of the research and analysis of the findings. Since the journal article was submitted, Boston Children's Hospital formed Epidemico to handle the licensing of HealthMap data for commercial companies. One of the study authors holds an equity stake in Epidemico. The other authors and editorialists have disclosed no relevant financial relationships.

Lancet Infect Dis. Published online May 13, 2013.