The current vaccination policies in Australia, Ireland, Italy, the United Kingdom and the U.S., may not be robust enough to keep measles at bay and prevent a resurgence of the infection, according to a study published in BMC Medicine.
Italian researchers used a computer model to show the evolution of measles immunity in seven countries between 2018 and 2050. The countries were Australia, Ireland, Italy, Singapore, South Korea, the U.K. and the U.S., all of which have a two-dose vaccine program and high rates of primary school involvement in vaccination programs. But the countries have different demographics and vaccination histories.
They found that with the current vaccination policies in these countries, five countries may not succeed in eliminating measles and preventing its resurgence through 2050. Only two of them, Singapore and South Korea, may be able to be able to eliminate measles, with current vaccination requirements keeping the proportion of the population susceptible to measles below 7.5 percent. Previous research shows that the proportion of the population that does not have immunity needs to stay at 7.5 percent or below to eliminate measles.
In 2018, the proportion of the population susceptible to measles in the seven countries ranged from 3.7 percent in the UK to 9.3 percent in Italy. In Australia, Ireland, the U.K. and the U.S., vaccination from routine programs would need to continuously cover more than 95 percent of the population to result in eliminating measles.