Image copyright Getty Images Image caption CDC Director Dr Brenda Fitzgerald says anti-vaccination sentiments in part spurred the shooting in Virginia
A sharp decline in vaccination rates across the United States has increased the risk of outbreaks of vaccine-preventable diseases, according to a new study.
About 80 million Americans are now unvaccinated – a rise of 14 million in two years, according to the CDC.
Current law prohibits under-vaccination.
Anti-vaccination activists have said their movement began after health authorities allowed the spread of vaccine-preventable diseases.
In December 2017, parents who chose not to have their children vaccinated – or who were unable to vaccinate them due to medical reasons – triggered an outbreak of measles in California.
One of the Californian women who became infected with the disease at Disneyland in 2014 was a mother who had elected not to have her child vaccinated.
At the time of the outbreak, there were about 30 people in California who were too unvaccinated to protect themselves from measles, but not enough to draw attention to the issue.
The California outbreak spurred the passage of legislation that requires parents who do not want their children vaccinated to wait at least three months before applying for a vaccination exemption.
Now, unvaccinated adults account for about 1% of the US population and the number of those who have not been vaccinated because of either personal or philosophical or religious objections to vaccines has quadrupled.
That has sparked fears over outbreaks of vaccine-preventable diseases, such as measles and whooping cough.
It also increased the risk of infection from other vaccines, which immunise not only people who have been exposed to diseases but also health workers, who can become seriously ill if they are exposed to vaccine-preventable diseases.
Image copyright Getty Images Image caption ‘Data shows that we need to do more’ to prevent vaccine-preventable diseases
That is why the CDC released a study, titled “Inadequate Adult Vaccination and Risks to Public Health,” that discusses vaccination uptake and impacts on vaccination and public health.
During a recent live chat on Facebook, the CDC’s Dr Brenda Fitzgerald said that although outbreaks caused by unvaccinated people in the community were rare, there were “anomalies” in public health based on the country’s changing climate.
In California and other states, it is difficult to combat unimmunised people by limiting access to services or stop them from getting insurance, Dr Fitzgerald added.
“But there are other ways we can do this,” she said.
“Data shows that we need to do more… we know that many adults are often unvaccinated and have a lower likelihood of acquiring immunity due to more modest conditions.
“It’s hard for them to vaccinate because they may be caring for children, so we have to give them more information about the benefits and risks of vaccinating.”
In Pennsylvania and North Carolina, people whose income levels and education levels are not high enough to have insurance can apply for a vaccine waiver. This option does not require written proof, unlike the current exemption for personal or philosophical reasons.
Image copyright Getty Images Image caption Tennessee and North Carolina currently allow people who make less than 200% of the poverty level to apply for exemption from vaccine immunisation
A CDC spokeswoman added that it was doing “extensive research in the field to engage young adults in a public health conversation”.
Some vaccine exemption movements began in the 1960s in the UK and North America. A movement based in California during the 1990s reached a peak in 2009, when about half of California’s kindergarten students were not fully vaccinated.
Many Americans started not having their children vaccinated because they were worried about the safety of vaccinations – claims that have been disputed by the CDC and other medical experts.
President Donald Trump said last month he is “pro-vaccine” but has also said he had a “lot of respect” for people who are anti-vaccine.
He said his son Barron had measles, which is contracted by being exposed to it during school, but not by having the vaccine.