Measles cases in the [b]United States[/b] are at their highest levels since 2000, when the disease was declared eliminated. This year 514 cases have been reported – more than double the previous high, in 2011 – and the number isexpected to continue to climb, reports [s]The Washington Post[/s]. One reason is vaccine refusals but, the report notes, 10% of the cases occurred in vaccinated individuals. This has been attributed to lack of seroconversion – when antibodies are not created in the vaccinated person –and also the fact that when a successfully vaccinated person ages, the concentration of antibodies decreases. Until about six or seven years ago, waning immunity to measles would not have been a major concern because the US had high levels of what is called herd immunity. But, the report says, the recent string of outbreaks will continue if immunisation levels remain low.
[link url=http://www.washingtonpost.com/national/health-science/measles-cases-are-spreading-despite-high-vaccination-rates-whats-going-on/2014/06/23/38c86884-ea97-11e3-93d2-edd4be1f5d9e_story.html]Full report in The Washington Post[/link]