Authorities in Samoa are racing to contain a deadly outbreak of measles , one of the world’s most infectious diseases, as the death toll climbed to 65 on December 7 and the number of cases passed 4,400 – more than 2 per cent of the Pacific nation ’s population. The government on Tuesday told Samoa’s 200,000 residents to hang red flags on the door of any house containing an unvaccinated person. Two days later, even the residence of Prime Minister Tuilaepa Sailele Malielegaoi had a red flag on its gate. The outbreak came after immunisation rates plummeted to just 31 per cent in the wake of the July 2018 deaths of two infants, who died shortly after receiving a wrongly mixed measles vaccination. The nurses responsible were jailed, but anti-vaccine sentiment spread widely on social media and was played up by anti-vaccination groups outside Samoa. Even the Prime Minister's residence has a red flag. Tuilaepa Sailele Malielegaoi had the jab the other day at the cabinet table, but clearly there's some here who need the needle. #SamoaMeasles pic.twitter.com/H03t5rn9L7 — Alex Perrottet (@alexperro) December 4, 2019 All but three of the deaths have been people under 20, with more than half of the victims under the age of four. Some families have lost multiple children, and nearly 150 new cases were recorded in the past 24 hours alone. After declaring a state of emergency and putting the nation on a two-day lockdown to conduct a door-to-door mass vaccination campaign, Tuilaepa’s government on Thursday arrested vocal anti-vaccination campaigner Edwin Tamasese and charged him with incitement. The government said it had been flooded with anti-vaccination material from groups based in the United States and elsewhere. Communications minister Afamasaga Rico Tupai said anti-vaxxers were hindering Samoa’s mobilisation to immunise 93 per cent of the population. “Don’t get in the way, don’t contribute to the deaths,” he warned anti-vaxxers. How did the outbreak start? After a traveller with measles who was not exhibiting symptoms arrived from New Zealand – which is experiencing an outbreak – in early October, the disease spread quickly among the unvaccinated population of Samoa. Public health experts say travel is a major reason for the spread of the disease, which can incubate for up to two weeks before symptoms appear. Raina MacIntyre, head of the biosecurity research programme at UNSW Medicine in Sydney, said: “You need very high rates of vaccination to stop the transmission – we still see travel-related outbreaks in Australia, despite having vaccination rates over 93 per cent.” Measles cases spike in Indonesia, Malaysia and Philippines as anti-vaxxers take to social media Four years ago, Samoa’s measles vaccination rate was above 80 per cent. But in the wake of the two deaths last year, which were incorrectly attributed to the vaccine itself rather than the error of the nurses, public trust in vaccine safety plummeted – and anti-vaccination sentiment from around the world swamped social media in the country. Low coverage rates made it easy for the disease to spread, and by mid-October there were 16 cases. “When an infected traveller arrives in a non-immune community, shedding the world’s most easily transmitted viruses, the result is exactly what we have seen in Samoa,” said Ian Mackay, a virologist at the University of Queensland’s Child Health Research Centre. Privileged anti-vaxxers are pretending to help the Samoa measles epidemic they helped cause by sending...vitamins? That's like the NRA sending band-aids to victims' families of mass shootings. No thanks. #Samoa #SamoaMeasles #antivax pic.twitter.com/4xsei2g2Db — TheReal Truther (@thereal_truther) November 27, 2019 What has the government done to contain the outbreak? Prime Minister Tuilaepa this week promised to bring vaccination coverage rates up to the 93 per cent recommended by disease experts. The government closed schools, banned people under the age of 19 from public gatherings, and made vaccination mandatory. On Thursday and Friday the country instituted a dawn-to-dusk curfew while health officials went door-to-door on an immunisation drive. Speaking to the South China Morning Post from capital city Apia this week, Unicef Pacific representative Sheldon Yett said the roads were empty except for vaccination teams, and there were long lines of mothers and children at government-run vaccination stations. Explained: how Taiwan’s Pacific allies are being wooed by mainland China The international community has mobilised to help the government of Samoa contain the outbreak. Unicef has provided more than 260,000 vaccines, Yett said. Additional medical personnel have been sent from the US, Australia, New Zealand and French Polynesia, as well as the World Health Organisation. But critics say that compared with the proactive moves made by neighbouring American Samoa, Fiji and Tonga – such as being sure incoming travellers have been vaccinated – Tuilaepa’s government was too slow in declaring an outbreak and moving to contain it. Infectious disease experts say if someone has been exposed to the virus, they could still be at risk for contracting it for up to two weeks after receiving the vaccine, though their risk of doing so is lowered. Why should Samoa’s outbreak make Asia worried? Public health experts warn that Samoa’s outbreak is a cautionary tale for any nation where the vaccination rate could drop below 90 per cent – and a deadly example of the effects of anti-vaccination movements growing around the world. Mackay at the University of Queensland said: “The world should be seeing the tragedy in Samoa for the threat it could be in their own backyards, should vaccination rates drop back.” In Singapore, where the measles vaccine is required for children to go to school, there is a 95 per cent vaccination rate. The country saw just 158 measles cases this year, according to the World Health Organisation, fewer than Australia’s 195. Malaysia – where measles vaccination rates are 96 per cent, but which has a vocal anti-vaccine movement on social media – reported 760 cases this year. US Coast Guard looks to bolster Pacific allegiances as Chinese clout grows The Philippines, which has a measles vaccine coverage of just 67 per cent, is facing the largest outbreak in Southeast Asia, with more than 42,000 cases reported this year. Samoa’s neighbours Fiji and Tonga have seen smaller outbreaks, but both have higher vaccination rates. Christmas is usually the busiest time of year for tourism in Samoa, but potential visitors and members of the Samoan diaspora alike have cancelled trips, jeopardising the 25 per cent of GDP that tourism contributes to the country’s economy. Fiji, where tourism contributes 40 per cent to GDP, could be even harder hit if holidaymakers stay away. Yett at Unicef Pacific said outbreaks could be avoided if the right precautions were taken. “You need to make the investments in immunisation and tackle cases quickly – treat a single case as an emergency.”