The immunization drive came in the wake of a measles outbreak in Vancouver and a string of individual cases on Vancouver Island and the 100 Mile House area, majority contracted while travelling.
Following Cook and Los Angeles counties on the list were Miami-Dade County in Florida, King County in Washington and Queens in NY, where John F. Kennedy and LaGuardia airports are located. Harris County ranked ninth and Tarrant County ranked 12th. They cited data from the CDC and various state health departments, which said that at least 45 US counties reported measles cases in 2019. Andrew Wakefield lost his medical license and the paper was retracted from The Lancet.
"These outbreaks can only happen if someone brings measles into the country and there's a low vaccination rate in a population", Gardner explained.
The annual number of measles cases in Australia has ranged between 10 and 340 since 2000, with the spike attributed to returned travellers. Although measles was officially eliminated from the U.S. in 2000, the ongoing outbreak shows that the nation remains at risk.
For the current school year, 1,447 students in the county were granted religious exemption status for immunizations, according to the Florida Department of Health. So, 4 to 5 percent of the people vaccinated rely on the rest of us to protect them.
The researchers observed that measles cases don't respect county lines and recommended that local officials be alert for outbreaks in adjacent counties. Their analysis is based on global air travel volume, non-medical exemptions from childhood vaccinations, population data, and reported measles outbreak information.
So far in 2019, Harris County has reported four cases of measles.
The model doesn't just factor in a county's vaccination rate (excluding people with medical exemptions) as past attempts to quantify measles risk have, but also where recent and current outbreaks elsewhere in the world have happened and their size, as well as the amount of global travellers from these countries that these counties typically receive. The reality is this: the majority of diseases have not disappeared - they simply have been prevented by vaccinations.
"We're just asking for the parental right to choose whether or not our children are vaccinated". The agency attributes the recent outbreaks to measles being imported, when an unvaccinated traveler visits a country where there is widespread measles transmission, gets infected with measles, returns to the USA and exposes people who are not vaccinated.
"We have long known that vaccine avoidance is a critical public health issue in the USA and Europe", Sahotra Sarkar, the study's lead author and a philosophy and integrative biology professor at UT Austin, said in a statement. The researchers warned the most at-risk areas that have yet to report a case are those with worldwide airports, such as Miami, Orlando and Tampa.
The analysis correctly identified regions in Washington, Oregon, and NY that have already seen major measles outbreaks this year.
Sarkar and colleagues listed counties that have not yet had a measles outbreak, but because they are close to major global airports, they are at risk of imported measles cases.
Travel to and from China, India, Japan, Mexico, the Philippines, Thailand and Ukraine appears to pose the greatest measles risk, according to the study. With the virus set to make a slow comeback in countries once hoped to be free of the disease, Australian health authorities can expect to see more outbreaks sparked by returning travellers, spreading predominantly in communities with low immunity.