Measles outbreaks across the country have created a public health crisis. Sometimes, infectious diseases spread because we don’t have the tools to fight them. That’s not the case with measles. Growing vaccine skepticism, fueled by misinformation, is largely responsible for the resurgence of this preventable, highly contagious virus.
Characterized by an angry red rash, fever, a dry cough and a runny nose, measles can be transmitted via sneezing, coughing or breathing. Complications from the virus can be life-threatening, and according to the Centers for Disease Control and Prevention, 1 or 2 in 1,000 children who have measles will die. The introduction of a measles vaccine in 1963 effectively curbed this once common, serious childhood illness. By 2000, cases of measles were so few and far between that the CDC declared the disease eliminated in the US. But that designation could change if the number of measles cases continues to climb.
If those were the only people in the country at risk of getting measles, there wouldn’t be a crisis.
So far this year, measles has resurfaced in 28 states, with the majority of cases concentrated in a few areas of the country, including in and around New York City and parts of California and Washington. Outbreaks have been linked to travelers bringing the disease back from countries with low vaccination rates. As of June 20, the CDC recorded 1,077 measles cases total. That’s the highest count since 1992 — and experts say it could indicate a reversal of progress against a disease we shouldn’t still be fighting.
Doctors and public health officials are worried about what’s to come, expressing concerns over the possibility of larger and more serious measles outbreaks, as well as other preventable illnesses making a similar resurgence. Here’s why measles is back, how we’re dealing with its return and what might happen next.
What’s behind the return?
In the US, the measles vaccine is bundled with inoculations against two other contagious illnesses, mumps and rubella; it’s collectively known as the MMR vaccine. The CDC recommends that children receive two MMR injections: first, around 12 to 15 months old, and again between 4 and 6 years old.
To be fully protected against any of these three illnesses, you need to receive both MMR injections. A few segments of the population haven’t, including very young children and people who have compromised immune systems or allergies to the vaccine. Many adults born before 1957 had measles as children, making them immune to reinfection, but those who never had it remain susceptible. Finally, pregnant women who haven’t been vaccinated fully can pass on measles to developing fetuses, potentially leading to miscarriage, stillbirth, low birth weight and increased risk of preterm delivery.
If those were the only people in the country at risk of getting measles, there wouldn’t be a crisis. When a large enough portion of the population is vaccinated against an infectious illness, we’re all protected from it, including those who haven’t been vaccinated. This concept is called herd immunity, and the percentage of people who need to be vaccinated to protect the whole herd varies from one disease to the next, depending on how transmissible it is.
For the flu, a 50 percent vaccination rate would do the trick. But measles is one of the most transmissible diseases around, requiring a 92 to 95 percent vaccination rate to build herd immunity against it. One sick person with measles will, on average, infect 18 others. So we can’t afford to let a swelling number of people opt out of vaccinating their kids.
“Vulnerable populations like pregnant women and younger children who are not eligible to be vaccinated rely on everybody else,” says Dr. Umair A. Shah, a physician and public health researcher who serves as the executive director and local health authority for Harris County Public Health in Texas. “We’ve taken our foot off the pedal with measles.”
New York State agrees. In June, Gov. Andrew Cuomo signed a law banning any unvaccinated children from attending school unless they have a medical exemption. For the sake of public health, Cuomo said, religious vaccine exemptions are no longer allowed.
The most commonly cited reasons for skipping vaccination, according to a 2016 study, include religious, personal or philosophical beliefs, safety concerns and a desire for more details from medical professionals. Study authors noted that “education is a key player in equipping parents with the necessary information so they can make responsible immunization decisions for their children.”
In 1998, one now-retracted study linked the MMR vaccine to autism. Despite being thoroughly debunked and denounced by autism advocates, the theory has proved hard to extinguish. In April, the CDC acknowledged that vaccine misinformation, shared quickly and easily online, has played a substantial role in the return of measles.
“Social media is not a credible news source,” says Shah. “There is a lot of credible information out there, such as through the World Health Organization, the CDC and the American Academy of Pediatrics.”
What’s next for measles?
It’s anybody’s guess how long the current spate of measles outbreaks will last. It would almost certainly help if other states followed New York’s lead on eliminating nonmedical exemptions. Still, Shah thinks things will get worse before they get better. “It will definitely go beyond the summer,” he says. “When you get into close settings, which happens during the winter months, typically during the holidays, that’s where you have the potential for transmission as well.”
To speed up the process of putting measles behind us (again), experts say it’s time to double down on education. The government could increase funding for vaccination advertising campaigns, create policies that lower or cancel out the costs of vaccines, and use archival images to show people what untreated measles and other preventable illnesses look like,” says Dr. Beulette Y. Hooks, a family physician and chair of the commission on the health of the public for the American Academy of Family Physicians. “Most people living today have not seen the effects of these illnesses on children and adults. If you have not seen how something affects a child, you are more likely to say it cannot happen to my child or grandchild.”
Ultimately, Shah says, current measles outbreaks should serve as another reminder to get vaccinated and stay up to date on immunizations. Even with advancements in medicine, there are so many diseases we don’t understand well. Measles is one we do. Why move backwards?
The other two
Since the MMR vaccine protects against two other illnesses, experts say they wouldn’t be surprised if mumps and rubella diagnoses rise as a result of declining vaccination rates. Mumps, a viral infection like measles, typically presents with swollen salivary glands (those telltale puffy cheeks). Other symptoms include fever, muscle aches and loss of appetite, and severe cases can require treatment in the intensive care unit. Rubella, also known as German measles, can cause a mild fever, rash and headache, says Shah, with complications including meningitis and encephalitis. For pregnant women, contracting rubella can lead to miscarriage or serious birth defects. The US sees fewer than 10 diagnosed cases each year.
A few mumps outbreaks have already sprung up, Shah notes. As of April 30, there were 1,002 mumps cases in 42 states in 2019. That number is above average, although not unheard of. Since the MMR vaccination program began three decades ago, a few hundred cases of mumps have typically been reported each year, with outbreaks occurring about every five years. But it hasn’t been five years since the last outbreak, which spanned 2015 to 2017 and involved about 9,200 reported mumps cases.
Beyond MMR
Shah also worries about under- or unvaccinated travelers picking up things like whooping cough (pertussis) and yellow fever, which can be transmitted to humans via mosquito bites.
“In the case of whooping cough, a recent Kaiser Permanent study suggested that it’s not necessarily just unvaccination or undervaccination, but rather waning immunity since the last time the child has been vaccinated that may be at play,” says Shah.
Americans aren’t routinely vaccinated against yellow fever because it’s not endemic to the US, but travelers can bring it back from parts of Africa and South America. In addition to avoiding mosquitos, Shah says, “It’s important for those traveling to such areas to get the yellow fever vaccine in advance. The CDC makes recommendations, but travelers can choose not to follow them.”
Unless a traveler is visiting a country that requires yellow fever vaccination for entry, it’s an optional precaution that someone might not take for multiple reasons, says Shah. For one thing, travelers’ vaccines typically aren’t covered by insurance.
While Shah hasn’t personally seen any data to indicate declining vaccination rates among travelers specifically, he says he wouldn’t be surprised to see such a trend emerge, given increased distrust of vaccination in general.
Quick facts
- Measles can linger in the air (e.g., after someone coughs) or on infected surfaces for up to two hours. An infected person can transmit the virus from four days before their rash appears to four days after it erupts.
- If you’re not sure whether you received both MMR doses, see your doctor about getting a booster shot. According to the CDC, “there is no harm in getting another dose of MMR vaccine if you may already be immune to measles (or mumps or rubella).” You can get a blood test to check for immunity (it’s the same blood test used to diagnose measles and mumps). If you were born before 1957, you’re presumed immune.
- Infants under 6 months old whose mothers are immune or vaccinated are presumed to have partial protection, but they shouldn’t knowingly be exposed to anyone with measles. If an infant is exposed, they should immediately see a doctor, who can administer immune globulin within six days of exposure to prevent or lessen the severity of an infection.
- Unvaccinated adults or older children who may have been exposed to measles should also seek immediate medical attention for an emergency vaccine (within 72 hours of exposure) or immune globulin.