Samoa might seem like a simple place to eradicate a disease. The Pacific island nation, halfway between Hawaii and New Zealand, has a land mass smaller than Rhode Island and a population of less than 200,000.

Effective vaccines against measles have existed for decades. Among them is the MMR vaccine, a single jab and booster that protects against measles, mumps and rubella. It has been administered in Samoa for more than a decade. Some 90% of infants in the country received the shot in 2013, according to the World Health Organization.

But last year, it became clear that, even in a small nation like Samoa, eradicating a preventable disease like measles was not simple at all. In less than four months, thousands of infants grew sick from measles and more than 80 people died, many of them very young.

The nation's health infrastructure was overwhelmed. "It happened so quick," said Fonoifafo Mcfarland-Seumanu, a public health nurse who joined the anti-measles campaign after winning the Miss Samoa pageant.

An array of local factors led to Samoa's outbreak. It was not, however, unique. Around the world, people die every year from outbreaks that vaccines could have quashed, from polio in Pakistan to human papillomavirus infections in Japan.

As the world grapples with the novel coronavirus pandemic and races to develop a vaccine to fight it, these outbreaks hold lessons for what lies ahead. Far from the end of the line, the discovery of a vaccine would mark the beginning of a new set of challenges in an era of fast-spreading misinformation and rampant public health policy missteps.

"Vaccines don't save lives," said Walter Orenstein, an associate director of the Emory Vaccine Center. "Vaccinations save lives. A vaccine dose that remains in a vial is zero-percent effective."

‘A false sense of security'

Measles spreads when an infected person coughs or sneezes. Among those confirmed to be infected, the death rate is 1.46%, deadlier than most estimates for COVID-19, the disease caused by the coronavirus. Before a vaccine became widely available in the 1960s, it caused millions of deaths worldwide annually.

Samoa has administered measles vaccines since 1982, according to national records, but it had not had an outbreak in years. "There was a false sense of security," said Sheldon Yetts, the UNICEF representative for Pacific island countries.

In July 2018, two infants died after receiving the vaccine. The Samoan government stopped its MMR program for nine months to investigate. A court later found the two nurses guilty of manslaughter — they had mixed a vaccine with muscle relaxant instead of water — and sentenced them to five years in prison.

"Everyone lost confidence," Mcfarland-Seumanu said. "Even some of the health-care professionals had doubts."

Anti-vaccination activists stoked a backlash, including Edwin Tamasese, a coconut farmer with no formal medical training, as well as Taylor Winterstein, the wife of an Australian rugby player.

Robert F. Kennedy Jr., the nephew of President John F. Kennedy and a controversial anti-vaccination activist, visited the islands in June 2019; he was photographed with Winterstein.

Vaccination rates, already lower than the roughly 95% required for herd immunity, plummeted to 31%. Experts cited a variety of reasons, including poor medical literacy and government inaction.

Then the outbreak began.

Samoa confirmed its first case of measles in September, probably imported from New Zealand. Within weeks, the outbreak was out of control. On Nov. 15, the government declared a state of emergency. Hospitals were as much as 300% past capacity.

The mother of the first child to die, 14-month-old Peter Von Heiderbrandt, begged families to get vaccinated. "These are our babies dying," she told a reporter. But the practical realities were immense.

"Most Samoans use traditional as well as scientific medicine and because of the confused response by the government to the measles epidemic, many were going to and fro in both systems," said Penelope Schoeffel, a sociologist at the National University of Samoa.

The government shut down the entire country on Dec. 5 and 6 for a sweeping door-to-door vaccination campaign. Unvaccinated families were asked to hang red flags outside their homes. Judith Esmay Ah Leong, a general practitioner in Apia, Samoa's capital, said doctors were shocked to discover "there were still people living off the grid and had no access to transport."

Tamasese was arrested on Dec. 5 after allegedly breaking a new law about spreading anti-vaccination views. Mcfarland-Seumanu said that even as the deaths racked up, she spoke to parents who were scared of vaccines, citing rumors they read on Facebook.

Only after 95% of eligible people were vaccinated on Dec. 29 did the government lift the state of emergency. "There wasn't a village that was not affected, one way or another, by the outbreak," Yetts said.

Anti-vaccine activism

As a small island nation, Samoa may seem a unique case. But most countries have anti-vaccine activists, including the United States. Such views tend can take deep root in societies where distrust of authority is widespread.

A polio vaccine was first discovered 70 years ago. It has largely been successful: Cases worldwide have decreased by over 99% since 1988. Yet wild transmission still occurs in Pakistan, Afghanistan and Nigeria. And last year, the number of cases in Pakistan surged to 147 — a five-year high that alarmed experts.

Experts say that the central problems in Pakistan are distrust and mismanagement. Among the Pashtun ethnic community, anti-vaccine sentiment was especially rife after the CIA used a door-to-door vaccination effort a decade ago to hunt for al-Qaida leader Osama bin Laden.

When rumors of vaccinated children falling sick in a village school spread last spring, it prompted a wave of violence against medical workers and their guards. Vaccination rates plummeted.

But vaccine hesitancy is not just the province of conspiracy theorists. Vaccines can be inconvenient. The oral vaccine that is prevalent in Pakistan (partly because it costs less) must be administered multiple times. Teams go door-to-door, leaving people jaded and skeptical of a formulation that involves a live virus.

"As a parent you're sick and tired of it, as a vaccinator you are sick and tired of it," said Babar bin Atta, the country's top anti-polio official until last year.

The Independent Monitoring Board of the Global Polio Eradication Initiative also blames senior Pakistani officials, arguing in 2018 that there had been "divisive and dysfunctional working relationships" within Pakistan's anti-polio and U.N. teams.

Dysfunction and division are not limited to developing nations. There is an effective vaccine for human papillomavirus (HPV), but the Japanese government avoided promoting its use for years, putting the lives of thousands of women at risk.

HPV, which is passed on through sexual contact, is remarkably widespread. Some strains of HPV can eventually lead to cervical cancer — it caused an estimated 266,000 deaths globally in 2012.

Japan's multidose HPV vaccination rate was once around 70%. But just a few months after it was added to the country's official vaccination program in 2013, media reports alleged shocking side effects, and the government pulled its backing.

The evidence of adverse side effects is slim. Doctors cautioned that only a tiny fraction of recipients reported symptoms. But the government hesitated, in part due to fear of legal repercussions, and the vaccination rate dropped below 1%.

Following a lengthy political battle, the HPV vaccine is expected to return to the country's immunization program this year. But the cost of the seven-year pause is high: A study published by the Lancet this year estimated that the crisis could result in up to 5,700 deaths unless coverage increases.

The coronavirus pandemic

Globally, more than a dozen COVID-19 vaccines have reached clinical evaluation already, with more than 100 others in the works. President Donald Trump has bragged of a "warp-speed" U.S. process for developing a vaccine, while other nations are racing forward with their own programs.

Some experts hope COVID-19 could go the way of smallpox, which was eradicated in 1980. "It's a hard time to be an anti-vaccination activist right now," said Riko Muranaka, a Japanese doctor and journalist who tracks HPV vaccine misinformation.

But vaccinating an entire planet is an enormous task. It took decades of work to eradicate smallpox. Similar efforts to quash measles and polio have yet to succeed. And the coronavirus pandemic is disrupting vaccination efforts, not aiding them. UNICEF warns that routine immunization services have been hindered in at least 68 countries.

Some advocates worry that the spread of coronavirus misinformation could fuel anti-vaccination sentiment. "Global narratives of vaccine development for COVID-19 may contribute to an upsurge in anti-vax messages, including in Pakistan," said Rana Muhammad Safdar, coordinator for Pakistan's polio program.

“If and when we get a COVID-19 vaccine, we will see claims about the vaccine being dangerous and ineffective join this story, regardless of what the evidence says,” said Julie Leask, a professor at the University of Sydney and an expert on vaccinations.

Polls show a significant minority of Americans say they would not get a coronavirus vaccine.

In Samoa, that may seem unlikely. The country, having learned just how hard it is to stop an outbreak once it begins, went into lockdown early this time around. It has not reported a single confirmed coronavirus case.

But anti-vaccination sentiment lingers.

Tamasese, the businessman arrested last year over allegations that he spread misinformation, said in an email that neither the measles outbreak nor the coronavirus pandemic has changed his mind. “My position on vaccination has actually been reaffirmed,” he wrote.