Samoa a measles threat to U.S.A, research finds
Samoa has among the highest risk of exporting measles to the United States of America.
This is according to new research from the Johns Hopkins Whiting School of Engineering published in the Lancet last month.
Using vaccination rates from U.S. counties and studying arrivals to the country, researchers calculate that Samoa, the Philippines, New Zealand, Israel and Ukraine pose the highest risk to the United States of America (U.S.).
While air travel is largely suspended while world grapples with the COVID-19 pandemic, the World Health Organisation is concerned the pandemic will majorly disrupt routine vaccinations like the measles, mumps and rubella (M.M.R.) vaccine, as might as growing vaccine hesitancy.
“Decreasing vaccination rates, combined with an increase in measles outbreaks abroad and high volumes of international travel, places the U.S.A. at increased risk of measles introduction and local outbreaks,” the researchers state.
“U.S. counties at high risk in this study could represent high risk locations for future COVID-19 outbreaks, if they remain similarly resistant to a COVID-19 vaccine; however, changes in risk perception could increase vaccine uptake.”
Between 2016 and 2018, measles cases shot up 167 per cent globally as vaccine coverage dropped, and in Samoa coverage loss resulted in at least 83 deaths, mostly of children, in late 2019.
Just four months in 2019, the U.S. was experiencing the highest number of cases across the country since the disease was eliminated in 2000, with 704 confirmed cases in 22 states.
Last May, the same researchers identified 25 U.S. counties most at risk of importing measles and experiencing an outbreak in 2019, based on air travel, vaccination data and population data.
Their research was published in the Lancet, and included an interactive web-based tool which coded each county by risk level.
In the months since the 2019 research was published, Samoa’s measles vaccination rate has improved dramatically, driven by a nationwide campaign that included shutting down the country for two days while mobile teams went door to door vaccinating people.
According to the latest W.H.O. estimates based on figures from the Ministry of Health, 87 per cent of eligible children received their first dose of M.M.R. and 44 per cent received their second.
The Johns Hopkins researchers said the main limitations in their study are that the risk model is unable to incorporate the risk for domestic spread. They were also only able to use WHO-confirmed measles cases, which may underestimate risk in counties with limit case confirmation capacity.
The effects of COVID-19 on M.M.R. rates globally have also not been factored into the study.