WASHINGTON – US public health experts sounded the alarm on Wednesday over the outbreak of measles in recent years, mostly in communities where people refuse vaccines and obtain waivers for religious or other reasons. "personal".
Since January 1, six outbreaks of the disease have been reported in the United States, for a total of 159 cases in the states of Washington, Colorado and New York.
Since 2000, between 50 and several hundred cases have been reported each year, although the highly contagious disease was declared eradicated at the beginning of the century.
His return is "really unacceptable," said Antony Fauci, director of the National Institute of Allergy and Infectious Diseases, at a congressional hearing. "We must reach zero."
The virus is one of the most contagious that we know. He may linger in a room or on an area up to 2 hours after the departure of the infected person.
In most measles outbreaks in the United States, the virus has been imported by travelers returning to the United States, the disease being very active in many other countries.
It then spreads among unvaccinated people, who tend to live close to each other.
"There are pockets of people who are reluctant to get vaccinated," said Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases (NCIRD).
In the past five years, 12 of the 26 measles outbreaks in the United States – an epidemic is defined as more than five people infected – have occurred in "welded communities," she said.
Three-quarters of cases are concentrated in such communities. Examples include an outbreak in the Somali community of Minnesota in 2017 and in the orthodox Jewish community of Brooklyn last year.
Experts pointed out that misinformation about vaccines is an important factor, accusing social networks of spreading false information about the risks associated with vaccination. Recently, Facebook, YouTube and Pinterest, under pressure from Congress, announced measures to block the content of anti-vaccines.
The MMR vaccine against measles, mumps and rubella is "incredibly safe," said Messonnier. Since its inception in the 1960s, millions and millions of doses have been administered, the most common side effect being painful arms.
"We are victims of our own success," said Messonnier.
While the number of measles cases has decreased by 99% since the 1960s, parents have become less aware of the risks posed by the disease.
Measles has already claimed 400-500 lives a year in the United States. In addition to fever, tiny red spots and other symptoms, complications of the disease include ear infections (1 in 10 cases); pneumonia (1 in 20 cases); and encephalitis, an inflammation of the brain (1 in 1,000 cases).
To achieve "collective immunity", in which unvaccinated people are protected by the high proportion of other people vaccinated, one needs to vaccinate between 92 and 95% of the population, said Fauci.
The national immunization rate for children is about that, but there are large disparities between states, from one city or school to another.
The most egregious example is Clark County, a jurisdiction located just north of Portland, Oregon, where are concentrated 65 of 159 measles cases in the United States.
Fifteen years ago, 96% of the county's 5-year-olds had been vaccinated against measles. During the 2017-2018 school year, this proportion had dropped to 84%.
In some schools, especially private schools, the MMR vaccination rate was as low as 20 or 30%.
Lawmakers in the state of Washington responded by proposing legislation that would eliminate exemptions for personal or philosophical reasons. The opt-out for religious reasons would remain. Other states are also considering a similar action.
In the United States, only 3 of the 50 states – California, Mississippi and West Virginia – grant exemptions only for medical reasons.