In 2000, the United States were declared measles free, due to high vaccine rates among the population. Two years before, the journal Lancet published a paper by Andrew Wakefield: in this paper the researcher stated a correlation between MMR vaccine (against measles, mumps and rubella) and serious complications like inflammatory diseases, regressive developmental disorder and autism. Many consider this the beginning of the anti-vaccination movement. However, in the following years it became clear that the data used by Wakefield were false: the paper was retracted and his medical license was revoked. His influence as a spokesperson in anti-vaccine groups, though, remained unchanged.
Although the vaccine coverage remains high, the relatively small drop in vaccination rates resulted in a significant increase in the number of measles outbrakes in the last two years, as shown by a report by the Centre for Disease Control.
In the early months of 2015 5 measles outbreaks happened already, often brought by tourists or visitors to the US but spreading in communities where groups of people are not immunized or whose immune system is not functioning properly because of other diseases. One example is the powerful outbreak that spread last December from Disneyland, in California: the vaccination rate of the people exposed may have been as low as 50%, and likely no higher than 86%. 147 Americans were infected, and the virus spread in other states, resulting in many cases in Canada, were the outbreak was active until April.
(Martina Di Ciano)