A friend called recently asking about measles. She’s the mother of four very young kids and wanted to know if she should be worried. She’d heard about the large measles outbreak in northwest Texas. Since January, more than 159 people are known to have been infected, and the outbreak has resulted in two deaths and dozens of hospitalizations. Now, this measles outbreak has spread into nine other states, and there’s an alert to travelers passing through the Los Angeles Airport.
Contrary to statements by Health Secretary Robert F. Kennedy Jr., outbreaks of this deadly disease are highly unusual. The U.S. declared measles eliminated more than 20 years ago, thanks to an exceptionally safe and effective vaccine. But efforts to undermine confidence in that vaccine have contributed to these recent outbreaks. There are things we can do, individually and collectively, to protect our most vulnerable and hopefully eliminate measles in this country again.
My friend understands the settled evidence behind the safety and efficacy of vaccines. She’s following the vaccine schedule her pediatrician recommended. Measles vaccines are among the most protective shots we have, so when she gets her kids vaccinated, they are protected. But the large outbreaks we are starting to see are still creating risks, including among our very youngest kids, our immunocompromised kids, and even among vulnerable adults.
Measles vaccines are highly effective: 93% after the first dose, 99% after the second dose. The problem is the timing. The first dose is not recommended until a child is 12 to 15 months old, and the second dose usually between the ages of 4 and 6. Infants have some passive immunity from their mom’s antibodies for the first 6 months, but not enough to be fully protective, which is why the U.S. Centers for Disease Control and Prevention strongly recommends that parents of children too young to be vaccinated avoid travel to areas with measles outbreaks.
Read More: What to Know About the Measles Vaccine
All children under the age of 1, before they get their first measles vaccine, are at risk if they come near someone with measles. Given that measles is one of the most contagious diseases on Earth, outbreaks mean we are likely to see more infections among children in this age range, including kids whose parents fully intend to vaccinate. And while the first dose is highly protective, the best protection comes after the second dose, which is usually given when a child is ready to start school. Between those two doses, children may still be at some risk, especially if they come into repeated contact with measles from others refusing or unable to be vaccinated.
Beyond the youngest kids, two other groups need special attention. The first is children who are immunocompromised. Some of these children, such as those undergoing cancer treatment, cannot get the measles vaccine because the vaccine is a weakened form of the live virus, and in someone who is immunocompromised, it can actually cause the disease. Therefore, these immunocompromised kids rely on high levels of population immunity to protect them. When population vaccination rates fall below 95%, the virus can begin to circulate, and vulnerable children can become infected and will get very sick if they do.
The second potentially vulnerable group are elderly and immunocompromised adults. Most elderly people should have some immunity against measles; people born before 1957 likely had measles, and starting in the 1960s, people started getting vaccinated (though through 1968, the available vaccine was a little less effective). In general, we assume that everyone has lifelong immunity, whether from an infection or vaccines. But we don’t really know for sure. If a senior in her 80s had measles when she was 5, is she still protected? What about an adult undergoing chemotherapy? Immunity in these two populations may hold up fine—but we urgently need studies to better understand the risks of being exposed to measles for these types of individuals. Measles in an elderly or immunocompromised adult who isn’t protected—either because they cannot be vaccinated or because their immunity has not held up over time—is likely to be quite severe. And it is possible that the elderly may need an additional shot to protect them if they live in a high outbreak area. We don’t know, and we can’t make recommendations without data.
Read More: A Study Retracted 15 Years Ago Continues to Threaten Childhood Vaccines
Years of scaremongering about vaccines have led to low vaccination rates in many communities across America. A now-standard refrain is that parents are simply putting their own kids at risk but not harming anyone else. The truth is this: low vaccination rates create risks for many others. They create risks for kids who are still too young to get vaccinated. They create risks for kids who are immunocompromised, who can’t get vaccinated. They may also create risks for older or immunocompromised adults whose immune systems are not robust enough to protect them.
So when my family friend with a child under one called about protecting her children, my advice was clear. Stay away from areas with outbreaks. Get your child vaccinated as soon as they are eligible, and encourage your friends and others in your community to do so, too—because while she can eventually get all of her children protected, no such option exists for the child battling leukemia. And no such option exists for all those who are immunocompromised or at risk because of waning immunity. We owe it to all of them to make sure we stamp out measles in the U.S. again.
The post Measles Is Back. And a Lot More People Are at Risk appeared first on TIME.
