(RxWiki News) Measles may seem like an ailment from a bygone era, but new evidence suggests that many US children may still be at risk today.
A new study from Emory University Rollins School of Public Health found that 1 in 8 US children may be at risk for measles infection due to recent gaps in vaccination rates.
"Although we eliminated continuous measles transmission in the United States about 15 years ago thanks to the effectiveness of the MMR vaccine and robust vaccination rates, these study results show that we can't get complacent," said lead study author Robert Bednarczyk, PhD, an assistant professor of global health at Emory, in a press release. "While we currently have overall immunity in the population that should prevent sustained measles transmission, if the virus is introduced, there is the potential for large outbreaks. This is because there are clusters of unvaccinated children in some communities, which could allow a large outbreak to occur with spread to similar communities."
Measles is a highly contagious virus that typically spreads through the air by coughing and sneezing.
This virus is so contagious, in fact, that 90 percent of all non-immunized people who are close to an infected person will also become infected, according to the Centers for Disease Control and Prevention (CDC).
Symptoms typically include high fever, runny nose, cough and watery eyes. Three to five days after these symptoms begin, a rash usually breaks out.
Measles can lead to serious complications such as pneumonia, encephalitis (brain swelling), hospitalization and even death. Children younger than 5 and older adults are especially at risk of complications.
While no specific antiviral treatment exists for the measles virus, measles can be prevented with the MMR (measles, mumps and rubella) vaccine.
The MMR vaccine is given to children in two doses: the first between age 12 and 15 months, and the second between ages 4 and 6. According to the CDC, one dose of the MMR vaccine is about 93 percent effective for measles prevention. Two doses are about 97 percent effective.
In 1980 (before widespread vaccination), measles caused an estimated 2.6 million deaths each year, according to the World Health Organization (WHO).
In 2000, however, measles was declared eliminated from the US. Measles is still common in other countries.
For this study, Dr. Bednarczyk and team looked at national vaccination rates from 2008 to 2013.
These researchers found that 12.5 percent of all US children (8.7 million) were not fully protected by vaccination, and therefore may be susceptible to measles. This was primarily due to not receiving the MMR vaccine, or only receiving one of the doses.
About 25 percent of children age 3 or younger were found at risk, while about 5 percent of 17-year-olds had never been vaccinated.
According to Dr. Bednarczyk and team, measles is not currently widespread thanks to herd immunity. This means that the majority of people have been vaccinated, which ensures the number of people vulnerable to infection is small.
But all that could change if these trends continue.
This study was presented Oct. 8 at the 2015 ID Week. Research presented at conferences may not have been peer-reviewed.
Information on funding sources and conflicts of interest were not available at the time of publication.