The United States has experienced a record number of measles cases this year — the highest number since 2000, the year that U.S. health officials declared that endemic measles had been eliminated from the country, according to new numbers released last week by the Centers for Disease Control and Prevention (CDC).
As of Oct. 31, there were 20 outbreaks and 603 individual cases of measles in 22 states, including Minnesota, which has had two reported cases so far this year.
To understand exactly how troubling those national numbers are, consider this: In 2011 — the year that, until now, had the most measles cases since 2000 — 222 people (including 21 Minnesotans) came down with the virus in the United States.
All outbreaks of measles since 2000 have occurred after people traveling to other countries became infected with the virus and then brought it back to the United States.
Measles is a highly contagious disease — one of the most contagious of those that can be prevented with a vaccine. The average person with measles would be able of infecting 12 to 18 other people if all of his or her contacts were unvaccinated or hadn’t developed immunity by already having had the disease, experts say.
Measles is also a serious disease, particularly in children under the age of 5 and in adults. Complications from the disease include diarrhea, dehydration, ear infections (which can result in permanent hearing loss), pneumonia, encephalitis, blindness and even death. In the United States, an estimated 0.1 to 0.3 percent of people who develop measles die from its complications. In the developing world, the death rate from the disease can be as high as 15 percent.
A single dose of the measles vaccine, if given before the second year of life, is 94 percent effective at preventing the disease. Two doses administered on or after a child’s first birthday and spaced at least a month apart protect almost everybody against measles for life.
The CDC, in conjunction with the World Health Organization, also issued an international report last week that had mixed news about measles. Between 2000 and 2013, vaccination programs have led to a 72 percent decline in the global incidence rate for measles and a 75 percent drop in the disease’s death rate. During that 13-year period, an estimated 15.6 million measles-related deaths were prevented — a stunning accomplishment.
But that progress has stalled. The number of deaths from measles increased from an estimated 122,000 in 2012 to 145,700 in 2013, mostly as a result of outbreaks in China, Nigeria and the Democratic Republic of the Congo, according to the report.
Reduced global funding for vaccination programs is a major factor behind those rising numbers, the health officials stressed.
What happens overseas has a direct effect on measles outbreaks in the United States. For, as two health experts note in a commentary published Oct. 30 in the New England Journal of Medicine, the contraction of the disease by susceptible U.S. residents travelling overseas is one of the major reasons behind the rising number of cases that are occurring here.
The other reason: the increasing number of U.S. parents who refuse or delay having their children vaccinated.
“Despite the overwhelming evidence that vaccines — including the measles, mumps and rubella [MMR] vaccine — are safe, too many people still believe that greater risk is posed by vaccinating than by not vaccinating,” the commentary’s authors write.
Measles in Minnesota
To find out about current measles trends here in Minnesota, MinnPost sent some questions last Friday to Emily Banerjee, an epidemiologist with the Minnesota Department of Health (MDH). Her lightly edited responses are below.
MinnPost: Is the MDH alarmed by the reported national jump this year in measles cases?
Emily Banerjee: Minnesota is concerned. With the exception of 2011, in which Minnesota had a measles outbreak of 21 cases, we have had an average of about one case per year since 2000. When there are more and more cases in the United States, there is a higher chance that Minnesota will also have cases as a result of people spreading measles to others during domestic travel.
MP: How many documented cases have we had this year in Minnesota?
EB: We have had two reported cases of confirmed measles in 2014. Measles is not a disease that is endemic in Minnesota, meaning it is not currently spreading among the population. MDH investigates suspect rash illness cases, and laboratories and health-care providers are required by law to report suspect cases of measles immediately to MDH so that we can collect the proper lab specimens and take immediate public health action if it turns into a case.
MP: What do we know about these cases? Were they contracted while the children’s families were traveling overseas?
EB: The first case contracted measles while traveling overseas and then transmitted measles to the second case (an adult business traveler) in passing at a U.S. airport gate. Both cases were confirmed by laboratory testing and had illnesses that were clinically compatible with measles, including high fever and maculopapular rash.
MP: What role did lack of immunization play in these cases?
EB: The first case was an age-appropriately vaccinated child with one dose of MMR, and represents the 2-5 percent of individuals who do not respond to the first dose (primary vaccine failure, which is why a second dose of MMR is routinely recommended). The second case had unknown vaccination status and is part of a large group of Americans born between 1963 and 1978 who may have received a far less effective version of the MMR vaccine.
MP: What is the current rate of childhood-disease immunization in Minnesota? Is it up or down from previous years?
EB: More than 90 percent of Minnesota kindergarteners were vaccinated against diphtheria, tetanus, pertussis, measles, mumps, rubella, polio, hepatitis B and chickenpox for the 2013-14 school year. MMR (measles, mumps and rubella) vaccination rates are steady from previous years — they have hovered at around 90 percent.
MP: How concerned are you and your colleagues about current trends in immunization?
EB: For the most part, we see level immunization rates, but, of course, we would like to see them inching upward. Most parents vaccinate their children. Parents who delay some vaccinations put their child at risk for serious diseases that can be prevented. Once those diseases are in your community, it may be too late for their child to get vaccinated. MDH does keep an eye out for areas where vaccine refusal is higher. This is done through the Annual Immunization School Report (AISR). Schools are a place where diseases can spread quickly among children who are unvaccinated.
MP: What should parents know about measles (and other childhood diseases) and immunizations for those diseases?
EB: Vaccination is one of the most amazing public health accomplishments that have happened in the past century. In years past, parents dreaded the diseases we no longer see. Measles is no exception. Measles is not a mild disease. Every day, somewhere in the world, 430 children die of measles. This is preventable. Two years ago, a young Minnesota boy almost died of pneumonia caused by measles. Parents have the power to prevent these diseases, including measles, from returning to our communities by making sure their child is vaccinated on time, every time.
You can read more about measles and its prevention on the CDC’s website.