As climate change causes more extreme weather events, increased rainfall and rising temperatures, it's increasing the spread of infectious diseases.
While this claim might sound like scaremongering, it is not a prediction — it's already happening now in our cities, as exemplified by news reports of the streets of Paris being fumigated to limit the spread of tiger mosquitoes known to carry Zika and dengue.
Vaccines are a key tool in the fight against these diseases. They can protect against some tropical and mosquito-borne illnesses, such as Japanese encephalitis, dengue or yellow fever, as well as many diseases that can thrive when drought and flooding reduce access to clean water, such as cholera and hepatitis A.
With new global pandemics also predicted to emerge with climate change, vaccines will likely play a key role in mitigating their most devastating impacts.
But troublingly, vaccine hesitancy appears to have increased since the COVID-19 pandemic, and it's not just COVID vaccines that are subject to this hesitancy, but vaccines more broadly — even those that have been successfully used for decades and led to the near-eradication of some infectious diseases.
Just a few days ago, the UK Health Security Agency warned that urgent action should be taken to curb the re-emergence of measles outbreaks caused by the decline in MMR (Measles, Mumps, Rubella) vaccine coverage in some communities.
The increase in vaccine scepticism presents a real challenge for healthcare organizations and national governments as they attempt to incorporate a climate resilience lens into their public health plans.
Almost a quarter of people have less confidence in vaccines post-COVID
The decline in vaccine confidence was a key finding of a study I carried out with my student Amy Tranter comparing survey data collected before and after the onset of the pandemic.
As part of this research, my students and I ran two anonymous online surveys of more than 1000 adults in November 2019 and January 2022 respectively, with the aim of investigating public perspectives on the practice of vaccination and the factors that might underpin hesitancy and refusal.
Both surveys asked respondents to indicate their attitudes towards statements including "vaccines are safe" and "I think vaccines should be a compulsory practice."
Because the second survey was carried out after COVID-19 emerged, it contained two additional questions specifically focused on that pandemic.
The results were troubling: They showed that confidence in vaccinations was considerably lower in 2022 compared to 2019 across all demographic groups.
Almost one quarter (23.8 percent) of participants in 2022 reported their confidence in vaccines had declined since the onset of the pandemic.
A decrease in vaccine confidence was found across participants' ages, genders, religious beliefs, education levels and ethnicities.
We found that, among our participants, some demographic groups were more vaccine-hesitant than others. In both 2019 and 2022, participants who held religious beliefs were more vaccine-hesitant than agnostic or atheist individuals. Respondents of Black and Asian ethnic backgrounds were also less vaccine-confident than White respondents in both surveys (although for the Asian participants this difference was only statistically significant in the post-pandemic survey.)
There was also a key age-related difference between the 2019 and 2022 groups: while middle-aged (46 to 60-year-old) respondents were more vaccine-hesitant than any other age group in the 2019 cohort, this was no longer the case in 2022, when middle-age participants appeared more confident than those between 18 and 30 years old.
This finding gels with previous findings of a separate survey carried out during the Delta wave of COVID, which indicated that "younger populations had less willingness to receive vaccinations".
The trend might also reflect the disproportionate severity of COVID in older patients, which may have prompted a higher perception of the infection risk in elderly participants, spurring a greater willingness to get vaccinated.
Ultimately, our research found that, despite the fact that the COVID-19 vaccines have allowed us to move past the acute phase of the pandemic and put lockdowns and social distancing behind us, vaccine confidence may have been yet another victim of COVID.
While the practice of vaccination has been met with controversy and opposition ever since its inception, the COVID vaccines were met with particularly heated scepticism and hostility.
Several studies have investigated the reasons for this hesitancy, including the role of social media in contributing to the spread of vaccine misinformation during the pandemic.
While some degree of scepticism is justifiable by weariness of a relatively new technology (mRNA vaccines) and concerns surrounding their fast development and testing times, COVID vaccines were the target of unprecedented levels of deliberate conspiratorial misinformation.
Countless fake news about the vaccines (for example allegations that they contain mind-control microchips or are part of a global conspiracy to sterilize the masses and depopulate the planet) have been fabricated for financial gain or political traction, and spread online at an alarming rate despite having been entirely debunked by fact-checkers.
More public education on vaccine safety is key
This decline in vaccine confidence post-COVID has significant public health implications — especially given that vaccine hesitancy was already a key threat to global health even before the pandemic hit.
The World Health Organization wrote in 2019 that vaccine hesitancy "threatens to reverse progress made in tackling vaccine-preventable diseases," pointing to the sharp increase in measles cases globally as a potent example of vaccine hesitancy in action.
Today, millions of children remain unvaccinated and therefore vulnerable to numerous vaccine-preventable diseases. We know that climate change disproportionately impacts the most disadvantaged and marginalized groups: in addition to the direct effects of climate change (e.g. floods and droughts), it is the poorest populations in developing countries who will likely suffer the most if vaccine hesitancy drives down vaccination rates.
Thus, rebuilding vaccine confidence must be a priority for all governments and health agencies seeking to build climate-resilient health systems. Ideally, authorities should consider specifically tackling vaccine hesitancy in their plans for climate adaptation.
Health authorities seeking to address vaccine misinformation should be non-judgemental in their approach, and mindful of cultural and religious factors that might underpin the hesitancy.
Vaccine communication works best when it is culturally appropriate and tailored to the individual's position on the vaccine hesitancy continuum: "By engaging with specific groups based on their concerns, discussions can be focused and are more likely to be productive and less confrontational," as researchers from The University of Melbourne have found.
Emphasizing support for vaccinations, rather than focusing on detractors and conspiracy theories, may also be a wise approach in attempts to overcome vaccine hesitancy, since research shows that making vaccine uptake visible will encourage vaccine acceptance as a social norm.
Public health campaigns should also emphasize the many success stories linked to vaccination campaigns throughout history, for example the drastic reduction in typhus, cholera, plague, tuberculosis, diphtheria and pertussis in the early 1900s, the elimination of polio, measles, mumps and rubella across several regions over the following decades, and the global eradication of smallpox in the 1980s.
Ultimately, it is essential to acknowledge that climate change and vaccine hesitancy are not only existential threats to our species, but also extremely polarizing and controversial topics. Considering the enormous political and financial interests at stake — think of the billions spent by fossil fuel lobbies to spread false narratives denying human impact on climate change — dispelling misinformation on these topics is one of the most challenging collective endeavors of our times.
To succeed, it is crucial that governments and health authorities work together with scientists, educators and community leaders to coordinate a response that is global in scale but tailored to individual local communities.
(The author is the Associate Head (Students) of the School of Biological Sciences at the University of Portsmouth in the UK. This article was originally published under Creative Commons by 360info)
