Measles and mumps, referred to as childhood diseases, that were claimed to be eliminated in the United States a decade ago are slowly making a comeback.
According to officials at Centers for Disease Control and Prevention (CDC) the resurgence of the disease is due to an increasing number of Americans choosing not to get vaccinated.
"I think one of the biggest misconceptions is that these diseases aren't a problem anymore," said Gregory Wallace, a medical epidemiologist with the CDC.
"People have associated vaccines with health risks and studies have not shown that to be the case," Wallace said.
In 2000, the CDC announced measles had been eliminated in the US. But in 2011, 220 Americans contracted the disease, the most cases the government health agency had seen in 15 years, officials said.
"It's one of the most contagious vaccine-preventable diseases," Wallace told RIA Novosti.
Approximately two-thirds of the 220 Americans who caught measles in 2011 fell ill because they had not received the measles vaccination and had contracted the disease during international travel or after coming into contact with someone who had been traveling, particularly in Western Europe, Wallace said. The remaining cases of infections were foreigners visiting the US.
In some cases measles can result in a serious lung infection, such as pneumonia. And while severe cases are rare, measles can cause swelling of the brain and even death particularly in infants and in people who have weakened immune systems including the elderly and those with HIV or types of cancer.
Mumps has also seen a resurgence in the US, though the circumstances surrounding the spike differ from measles, CDC officials said.
"The vaccine advocacy for mumps isn't quite as good as measles," Wallace said. "In certain settings if mumps gets a foothold in a community it can sometimes overwhelm the vaccine."
And because the virus has mutated in recent years, the standard vaccine has become less effective, CDC officials said.