The plummeting trust can be traced to 2015, when the government of the Philippines began a large-scale dengue fever vaccination program after an increase in cases of the mosquito-borne disease.
An election in 2016 saw a change in government, as President Rodrigo Duterte came to power.
Then, in November 2017, the French company Sanofi, which makes the vaccine, called Dengvaxia, said it posed a risk to people who had not previously been exposed to dengue fever. If they later became infected, they could have a more severe case of dengue, according to the company.
Philippines concern to outrage
Most countries adapted to Sanofi's announcement by updating guidelines and labeling. In the Philippines, public concern turned to outrage, which was fueled by a highly politicized response from the government, according to lead researcher Professor Heidi Larson.
"This was an opportunity to jump on the previous government for all their wrongdoings 'Why did you get this vaccine?' And it became an uproar and created not only quite a crisis around this vaccine, but it bled into other areas of public confidence in vaccines more broadly," Larson told VOA in a recent interview.
The researchers measured the loss in public trust through their ongoing Global Vaccine Confidence Index. In 2015, 93 percent of Philippine respondents strongly agreed that vaccines were important. This year, that figure has fallen to just 32 percent, while only 1 in 5 people now believes vaccines are safe.
Boxes of anti-dengue vaccine Dengvaxia are placed inside a freezer for storage at the Manila Health Department in Sta Cruz, metro Manila, Philippines.VOA
Risk of pandemic
"This dramatic drop in confidence is a real concern about risks to other diseases such as measles, on the one hand. On the other hand, too, Asia is ripe for a pandemic in influenza viruses to take hold, and in the case of a pandemic or an emergency outbreak, that's not a time when you can build trust," said Larson, who also cautioned that misinformation played a big part in undermining confidence in vaccines.
"The role of social media in amplifying those concerns, in amplifying the perception of risk and fears and their public health consequences, is dramatic," Larson said.
Large-scale immunization programs are in the trial stage to tackle some of the world's deadliest diseases, like malaria. Meanwhile, containing the outbreak of any future pandemic, like influenza, would likely rely on emergency vaccinations.
The report authors say it is vital that governments and global institutions do more to build public trust in vaccines. (VOA)