Kiwis are becoming increasingly wary of vaccine safety, despite remaining confident in their effectiveness, a new survey has found.
Researchers in the UK interviewed hundreds of thousands of people in 149 countries, including New Zealand, on whether they think vaccines are important, effective and safe.
Only 40.1 percent of Kiwis surveyed strongly agreed vaccines are safe, down from 44.6 percent in 2015.
"There is a growing public perception globally that vaccines are not safe, even though they are incredibly safe," said Helen Petousis-Harris, vaccinologist at the University of Auckland.
The interviews were carried out in 2019, before the COVID-19 pandemic.
The anti-vaccination movement, sparked by a fraudulent 1998 paper which linked vaccines to autism, has grown in strength in recent years. While some people do have adverse reactions, in vaccines that have been through trials and approved for use, it is incredibly rare.
The World Health Organization (WHO) has declared the anti-vaccination movement one of the top 10 threats to global public health.
"The health sector needs to do better at communicating - by using messages that resonate with a range of population groups, that are delivered by people who are trusted, and that use platforms that are relevant for people."
The WHO says vaccines prevent 2 to 3 million deaths every year. The US Centers for Disease Control and Prevention says thanks to vaccines, diseases like polio, tetanus, the mumps, rubella and diptheria are now rare. Smallpox, estimated to have killed hundreds of millions of people in the 19th and 20th centuries, was declared eradicated in 1980 thanks to vaccines.
Measles killed 140,000 people in 2018 - up 27 percent on the year before, thanks to declining vaccination rates.
While Kiwis' trust in vaccine safety has been declining, most still think they're important - 67.5 percent, up from 67 in 2015 - and effective - 58.7 percent, up from 58.2.
"New Zealand is no exception to changes in public attitudes around vaccination and it is not always good news," said Dr Helen Petousis-Harris.
Several countries have recorded massive rises in vaccine skepticism, including Afghanistan, Indonesia, Azerbaijan, Nigeria, Pakistan, Serbia, the Philippines and South Korea.
One of the biggest drops in confidence came in Indonesia, the researchers blaming "Muslim leaders questioning the safety of the measles, mumps, and rubella (MMR) vaccine, and issuing a fatwa (religious ruling) claiming that the vaccine was haram (forbidden) and contained ingredients derived from pigs, as well as local healers promoting natural alternatives to vaccines".
The research found those who trust family and friends for medical advice were least likely to get vaccinated, along with the less educated and religious groups.
"One of the main threats to the resilience of vaccination programmes globally is the rapid and global spread of misinformation," said Heidi Larson from the London school of Hygiene & Tropical Medicine, UK, who led the research.
"When there is a large drop in vaccination coverage, it is often because there's an unproven vaccine safety scare seeding doubt and distrust."
Nikki Turner, director of New Zealand's Immunisation Advisory Centre, blamed growing distrust of vaccines in some parts of the world on "outrageous examples of major international leadership that pays minimal or no attention to accuracy or honesty".
Some of the world's most powerful leaders, such as the US' Donald Trump and Brazil's Jair Bolsonaro, have repeatedly made false statements during the coronavirus pandemic. Trump has also in the past blamed vaccines for autism, a claim which has been rejected by virtually every study into the matter in the past decade.
"Overall, it is a mixed picture across the world. Many countries/regions continue to maintain good levels of confidence, some struggle and some have seen quite major shifts.
"I am frequently hearing doomsday scenarios of total loss of confidence widespread internationally in vaccination programmes, but this is not what this study is showing. For example there are signs that vaccine confidence is increasing for much of Europe."
The countries with the highest level of trust in the importance vaccines in 2019 were Iraq, Liberia and Senegal. At the opposite end were Hong Kong, Russia and Albania.
The study was published on Friday in journal The Lancet.