What you need to know:
- At least 63 people, mostly children, have died since the outbreak began in mid-October, with the crisis blamed on so-called "anti-vaxxers" convincing parents that immunisations were dangerous.
Samoan authorities warned Friday that anti-vaccine propaganda would not be tolerated, after a social media campaigner was arrested for opposing a mass immunisation drive aimed at containing the Pacific nation's deadly measles epidemic.
At least 63 people, mostly children, have died since the outbreak began in mid-October, with the crisis blamed on so-called "anti-vaxxers" convincing parents that immunisations were dangerous.
Samoa was on Friday enduring its second day of a lockdown as government and aid workers spread out across the nation of 200,000 people to vaccinate as many as possible.
But Communications Minister Afamasaga Rico Tupai said anti-vaxxers spreading conspiracy theories were hindering the unprecedented public health mobilisation.
"The anti-vaxxers unfortunately have been slowing us down," he told TVNZ.
"We've had children who have passed away after coming to the hospital as a last resort and then we find out the anti-vaccine message has got to their families and that's why they've kept these kids at home."
He warned anti-vaxxers: "Don't get in the way, don't contribute to the deaths".
The government-backed its tough rhetoric by arresting vocal anti-vaccination campaigner Edwin Tamasese late Thursday and charging him with incitement against a government order.
Officials said they acted after Tamasese had ignored previous warnings to stop his campaign.
Tamasese, who has no medical training, has railed against vaccines on his Facebook page and advocates using quack remedies such as papaya leaf extract to treat measles.
In a final post on Thursday before his arrest Tamasese described the vaccination drive as "the greatest crime against our people", and said vitamin C would save children.
The post had more than 7,000 shares, comments or interactions.
The government has special powers after declaring a state of emergency to deal with the measles crisis and the Samoa Observer reported that Tamasese could face two years in jail.
However, officials in the Pacific can do nothing about foreign-based anti-vaxxers, who the Observer reported were swamping government websites with material that Tupai described as "nonsense".
Examples include Texas-based conspiracy theorist Ellen Dann, who claims the vaccines, not measles, have caused Samoa's mounting death toll as part of a scheme by pharmaceutical companies to sell more medicines.
Prime Minister Tuilaepa Sailele Malielegaoi said Thursday's first day of the shutdown was a success, with 17,500 people, or almost 10 percent of the population, receiving their jabs.
As part of the lockdown, all businesses and non-essential government services were closed and residents ordered to obey a dawn-to-dusk curfew.
Families were also ordered to display a red flag outside their home to alert mobile immunisation teams if people inside were unvaccinated.
Yet the infection continued to spread, with the health ministry reporting on Friday morning 140 new cases over the previous 24 hours.
One more person died, bringing the confirmed death toll to 63, with 55 of the victims aged four or under.
Twenty children were critically ill in hospital, according to the ministry.
Infants are the most vulnerable to measles, which typically causes a rash and fever but can also lead to brain damage and death.
Samoa's measles immunisation rate dropped to about 30 percent after an incident last year involving the death of two babies that anti-vaxxers incorrectly blamed on the medication.
The drastic action currently underway is aimed at lifting the rate to the global standard of 90 percent, which should help curb the current outbreak and stop future epidemics.
UNICEF's regional chief on Thursday told AFP that social media giants such as Facebook and Twitter were "incredibly irresponsible" for allowing the misinformation to spread on their platforms.
Samoa has received aid to combat the crisis from Australia, New Zealand, France, Britain, China, Norway, Japan, the United States and the UN.
But Malielegaoi appealed for more aid from the international community.
"Health facilities have been overwhelmed in coping with the influx of patients," he said.
"The impacts of this emergency will be far reaching on Samoa and our people particularly our young generations."