According to the World Health Organization (WHO), people who reject the science and efficacy of vaccines are among the top 10 health threats facing the world in the coming year.

The report comes in the wake of a study published by the science journal PLOS ONE that shows anti-vaccine sentiment is growing in the United States.

“Since 2009, the number of ‘philosophical-belief’ vaccine non-medical exemptions has risen in 12 of the 18 states that currently allow this policy: Arkansas, Arizona, Idaho, Maine, Minnesota, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Texas, and Utah,” the authors of the study wrote.

The Centers for Disease Control report that the percentage of children age 19 to 35 months who’ve remained unvaccinated has quadrupled since 2001.

In the report, WHO says that “vaccine hesitancy” threatens to “reverse progress made in tackling vaccine-preventable diseases.”

Measles, for example, has seen a 30% increase in cases globally. The reasons for this rise are complex, and not all of these cases are due to vaccine hesitancy. However, some countries that were close to eliminating the disease have seen a resurgence.

WHO’s report mentioned some of the reasons people are resistant to vaccination, among them being complacency, lack of confidence in established science, and “inconvenience” when it comes to seeking out places where vaccines are administered.

In recent years, the U.S. has had multiple vaccine-preventable disease outbreaks triggered by people who refuse to vaccinate.

In November of last year, Asheville Waldorf School in Asheville, N.C. saw over 36 children infected with chicken pox, making it the worst outbreak the state has seen since the vaccine was made available to the public 23 years ago. As The Washington Post pointed out, the school had become a stronghold for parents who refuse to vaccinate their children.

According to an analysis published July of last year in the journal JAMA Pediatrics, a 2013 measles outbreak linked to a vaccine-denying community in Brooklyn, New York, cost the city’s health department an estimated $394,448 in the resulting outbreak response.

In a widely reported case from 2017, a Somali community in Minnesota was fooled by anti-vaccine activists who organized local meetings designed to disseminate the claim that vaccines are linked to autism. As a result, vaccination rates in the community plummeted, and soon there was a full-blown measles outbreak.

Here are the other threats facing 2019 as cited by WHO:

Air pollution and climate change

“Microscopic pollutants in the air can penetrate respiratory and circulatory systems, damaging the lungs, heart and brain, killing 7 million people prematurely every year from diseases such as cancer, stroke, heart and lung disease. Around 90% of these deaths are in low- and middle-income countries, with high volumes of emissions from industry, transport and agriculture, as well as dirty cookstoves and fuels in homes.”

Noncommunicable diseases

“Noncommunicable diseases, such as diabetes, cancer and heart disease, are collectively responsible for over 70% of all deaths worldwide, or 41 million people. This includes 15 million people dying prematurely, aged between 30 and 69.”

Global influenza pandemic

“The world will face another influenza pandemic – the only thing we don’t know is when it will hit and how severe it will be. Global defences are only as effective as the weakest link in any country’s health emergency preparedness and response system.”

Fragile and vulnerable settings

“More than 1.6 billion people (22% of the global population) live in places where protracted crises (through a combination of challenges such as drought, famine, conflict, and population displacement) and weak health services leave them without access to basic care.”

Antimicrobial resistance

“Antimicrobial resistance – the ability of bacteria, parasites, viruses and fungi to resist [antibiotics, antivirals and antimalarials] – threatens to send us back to a time when we were unable to easily treat infections such as pneumonia, tuberculosis, gonorrhoea, and salmonellosis.”

Ebola and other high-threat pathogens

“In 2018, the Democratic Republic of the Congo saw two separate Ebola outbreaks, both of which spread to cities of more than 1 million people.”

Weak primary health care

“…many countries do not have adequate primary health care facilities. This neglect may be a lack of resources in low- or middle-income countries, but possibly also a focus in the past few decades on single disease programmes.”

Dengue

“Dengue, a mosquito-borne disease that causes flu-like symptoms and can be lethal and kill up to 20% of those with severe dengue, has been a growing threat for decades.”

HIV

“…the epidemic continues to rage with nearly a million people every year dying of HIV/AIDS. Since the beginning of the epidemic, more than 70 million people have acquired the infection, and about 35 million people have died.”