AsianScientist (Oct. 18, 2018) – The Philippines’ highly politicized response to newly-reported risks of a dengue vaccine led to a dramatic drop in public trust in vaccines, according to a study published in Human Vaccines & Immunotherapeutics.
Dengue is a viral infection spread mainly by the bite of the Aedes aegypti mosquito, which is widespread in the Southern hemisphere. The symptoms of infection include fever, headache and pain in the joints and muscles. In some cases, death may even occur.
With the number of dengue cases in the Philippines rising from 2012 to 2015, it was hoped that an immunization campaign with a new dengue vaccine licensed in December 2015 (Dengvaxia), would stem the spread. However, in November 2017, the manufacturer, Sanofi Pasteur, announced that Dengvaxia posed a risk to people who had not previously been exposed to dengue.
While other countries dealt with this assessment by updating their guidelines and labeling accordingly, the news triggered outrage and political turmoil in the Philippines, leading to broken public trust in the dengue vaccine and anxiety around vaccines in general.
In the present study led by the London School of Hygiene & Tropical Medicine (LSHTM), UK, researchers measured the impact of the Dengvaxia crisis on overall vaccine confidence before and after the manufacturer highlighted the risk associated with the vaccine. The study of 1,500 participants revealed a dramatic drop in vaccine confidence. Whereas in 2015, 93 percent of the participants strongly agreed that vaccines are important, this statistic fell to just 32 percent in 2018.
The positive perception of vaccine safety also took a hit. In 2015, 82 percent of the participants strongly agreed that vaccines are safe. This was reduced to 21 percent in 2018. Similarly, confidence in the effectiveness of vaccines dropped from 82 percent in 2015 to 22 percent in 2018.
“The Sanofi announcement was a spark that fueled the flames of underlying political ferment in the Philippines. Health authorities and immunization programs cannot solve political tensions, but trust issues and potential areas of anxiety and possible dissent must be considered in advance of a pandemic. This is especially important in an era of social media and the ability for mis-information to be spread far and wide at the touch of a button,” said lead author Professor Heidi Larson, director of the Vaccine Confidence Project at LSHTM.
“We cannot wait until pandemics strike; we must make trust-building an ongoing effort, preparing the ground for the next ‘big one’, when trust and cooperation will be key to containing the spread of disease and mitigating its health and societal impacts,” she added.