AsianScientist (Dec. 21, 2018) – In November 2017, Sanofi Pasteur announced that its Dengvaxia dengue vaccine—the world’s first—could worsen the disease in vaccinated people who have not had a previous dengue infection.
While other countries responded to the news by updating their vaccine use guidelines and labelling, the announcement triggered panic, outrage and political turmoil in the Philippines, one of the first countries in the world to license Dengvaxia.
Authorities there swiftly suspended the mass vaccination campaign already underway to immunize one million schoolchildren, with some lawmakers calling for criminal charges to be filed against senior health officials who had pushed for the vaccine. Meanwhile, the Philippine Public Attorney’s Office proceeded to autopsy the bodies of several children, concluding—without evidence, other experts have pointed out—that Dengvaxia had caused their deaths.
This public health nightmare has far-reaching consequences. In the wake of the Dengvaxia controversy, public confidence not just in Dengvaxia, but in vaccines in general, has fallen precipitously in the Philippines, according to a new study published in Human Vaccines and Immunotherapeutics. In 2015—pre-Dengvaxia—82 percent of the study’s 1,500 respondents felt strongly that vaccines were safe; by 2018, after Dengvaxia was suspended, this number had fallen to just 21 percent.
Less vaccination, more vulnerability
“Based on reports from the Philippines, we had anticipated that there would be some decline in vaccine confidence, but we had not expected it to be as dramatic a drop as our results found,” said Dr. Heidi Larson, director of the Vaccine Confidence Project at the London School of Tropical Medicine and Hygiene (LSTMH), who led the study.
Falling vaccine confidence levels can translate into parents refusing or delaying critical immunizations for their children, such as the measles-mumps-rubella and diphtheria-tetanus-pertussis vaccines, said Larson. Adults may also be less willing to accept important vaccines beyond Dengvaxia, such as those against influenza, Larson added; over time, this could leave the Philippines more vulnerable to infectious disease outbreaks that now criss-cross the globe at the speed of air travel.
The Philippines is already seeing upticks in the incidence of vaccine-preventable diseases like measles, especially in areas with low vaccine coverage and disaster zones, said Dr. Lulu Bravo, a professor and infectious diseases expert at the University of Philippines Manila.
While these outbreaks have prompted health authorities to scale up public awareness campaigns and undertake personnel changes and other reforms aimed at restoring public trust, it remains to be seen whether or not such measures will improve outbreak preparedness, said Bravo.
“If the trend of low vaccine coverage continues, it’s only a matter of time [before] the Philippines will become the ‘sickest country in Asia’, with possible loss of visitors, tourists and worse, economic opportunities,” she cautioned.
A setback for dengue control
In the Philippines, a country with more than 180,000 dengue cases reported every year, the controversy will make it very difficult for any future dengue vaccine—even a safer one—to be reintroduced, said Dr. Martin Hibberd, a professor of emerging infectious diseases at LSTMH, who works extensively in the Philippines on dengue surveillance and epidemiology. [Disclaimer: the writer was a postdoctoral fellow in Hibberd’s former laboratory at the Genome Institute of Singapore.]
“I think we’d all like [vaccine manufacturers] to do better next time, but it would be a hard sell to try and release [a dengue vaccine] in the Philippines at the moment. You’d be very brave to do it in the current environment,” said Hibberd.
Feeding into public mistrust is the sense that the decision to greenlight the Dengvaxia campaign—against the advice of some experts, who urged caution—was politically motivated.
“I think people question why the Philippines was the first [to roll out mass vaccination]—people just assume there must be some political motive behind that,” said Hibberd.
Given the enormous problem that dengue presents in the Philippines, the government was likely eager to be seen as doing something useful to alleviate it, he added.
The fallout may also affect clinical research beyond dengue. According to Bravo, the Dengvaxia scare has made it difficult for some research sites to recruit subjects for drug and vaccine trials, including trials of dengue, influenza and inactivated polio virus vaccines; Bravo herself has had a respiratory syncytial virus vaccine trial cancelled due to problematic recruitment post-Dengvaxia. Local health officials afraid of possible repercussions may also be more reluctant to approve investigators’ requests to conduct research in their jurisdictions, she added.
“It is dismaying that these issues would serve as a deterrent to research and development in [the Philippines]… [it will be a major challenge to] restore vaccine trial confidence among politicians and policy makers, for them to support research and development among their constituents,” said Bravo.
Science, not politics
Ultimately, the problem is that Dengvaxia is now seen as a social-political issue rather than a medical or technical one, said Hibberd. While technical issues can be handled in a rational, evidence-based manner—for example, health authorities could consider administering Dengvaxia only to people who have had a previous dengue infection—political issues are much harder to deal with.
“Once it becomes a political concern, it’s hard to come back. Scientists can get up and say anything medically accurate, but if [the public] says, ‘Oh, they’re just agenda-motivated’, it’s hard to come across as convincing,” said Hibberd.
Post-Dengvaxia, the road to rebuilding public confidence looks set to be a long one. The fallout from the controversy has tainted even non-vaccine-related public health projects, such as a government-led deworming program, said Larson.
“This means the lack of trust in vaccines is part of a broader loss of trust in the Department of Health, so trust in health leadership needs to be restored first,” she said.
Restoring confidence is a collective effort, with a need for health authorities, health workers, medical and civil societies and other vaccine advocates to work together, said Bravo; these efforts could also engage scientists, philanthropists, celebrities, politicians and the media, she added.
The scientific community, for its part, also needs to step up to advocate for vaccines, said Hibberd.
“We’re the ones best placed to use science to help with [restoring confidence]… it feels very difficult to do that in the current situation in the Philippines, but now is probably the right time to begin that process,” he said. “There has to be an end to the blaming and a start to the rebuilding.”
This article is from a monthly column called The Bug Report. Click here to see the other articles in this series.
Copyright: Asian Scientist Magazine; Photo: Shutterstock.
Disclaimer: The writer was a postdoctoral fellow in Hibberd’s former laboratory at the Genome Institute of Singapore. This article does not necessarily reflect the views of AsianScientist or its staff.