Five years after COVID-19 was declared a pandemic, we seem to have a lot more contagious disease, not less. Some have called it the "Plague Years," or as journalist Ed Yong once described it, we might be living in the Pandemicene, “an era defined by viruses’ power over us.” The various conquered or almost conquered diseases making a comeback in these late years of COVID include tuberculosis, polio, syphilis, even dysentery. Also back is the world’s most infectious disease: measles. In the first decade of tracking measles cases and deaths after it became a reportable disease in 1912, an average of 6,000 Americans died from the disease each year. But a vaccine for measles (now given as MMR, a three-in-one shot that also protects against rubella and mumps), has been available in the U.S. since 1963, when it was received with joy and relief. Measles was declared eliminated (meaning no local spread in a 12-month period) from the United States as of 2000. It was the largest country to have achieved this milestone. Worldwide, vaccination has prevented an estimated 57 million deaths since 2000. But cases have surged since the COVID pandemic. Some 107,500 people around the world died from measles in 2023 (and it was worse the year before); most of them were children under five. As the Centers for Disease Control and Prevention reports, “Because measles is highly infectious, failures of routine immunization services to reach children are rapidly revealed by the occurrence of outbreaks primarily affecting unvaccinated children.” And indeed, in some areas, vaccination is becoming less fashionable. In a recent outbreak, lack of vaccination resulted in more than 200 cases so far, most concentrated in West Texas and New Mexico, with two deaths: a Texas child and a New Mexico adult, marking the first measles deaths in the U.S. in a decade. Neither victim had the vaccine (and, mind you, even vaccinated people still have a small risk of infection: the vaccine protects 95 percent of children who receive one dose of it and in 99 percent of those who receive the second dose, but this means breakthrough infections are still possible). The outbreak is still expanding. If not shots, why not host a version of the 1970s chicken pox party? These social gatherings were designed to deliberately sicken children to "get it over with" in the days before vaccines existed. Though there has been no confirmed cases of this happening in the recent outbreak, Texas health officials have warned against the practice (which was documented in New York during a 2018-19 outbreak, contributing to rapid spread) and urged patients to get vaccinated. Some folks are definitely listening, with some Texas cities running out of MMR vaccines due to sudden increased demand. While those behind the anti-vaccine movement have been busy reminding us that only a few children die of measles — tell that to their bereaved parents — they fail to point out a few vital things: One, that death is far from the only bad outcome to worry about. Two, that the claim that “I had measles as a kid and I’m fine” is a flagrant example of survivorship bias. Sadly, dead men, and dead children, tell no tales. “It’s kind of a challenge working on measles,” Dr. Natasha Crowcroft told Salon in a video interview from Geneva, where she works as senior technical adviser (specializing in measles and rubella control) at the World Health Organization. “Because everyone thinks ‘it’s just measles’. And there’s that ‘oh, I had it and I was fine’ kind of narrative you hear.” Crowcroft says one of the reasons it’s difficult is because "actually, most people are fine. It’s a bit like driving a car compared to flying in a plane. Most people who drive a car are fine, and most people who fly in a plane are fine. But everyone worries about the plane, because if something goes wrong, it goes really wrong … So everyone gets measles if you don’t have the vaccine, and most people are fine. But because everyone gets measles these rarer effects actually end up being quite common.” And indeed, in order to keep measles out of a community the vaccination rate in that community needs to stay above 95%. We’re not there anymore. Of all human-infecting pathogens, measles has the highest basic reproduction number; that is, the average number of people who will be infected by a single case in a freely circulating population. For every measles case, 12-18 other people will be infected with the disease. About enough for a party. “The reality is, we were in a much better place in 2019 than we are today,” Dr. Maimuna Majumder, a computational epidemiologist and faculty member at Harvard Medical School and Boston Children’s Hospital, told Salon in an email. “Even nationally, our vaccination rates have dropped below what is required for herd immunity against measles. This means that we have even more pockets of undervaccinated kids than we did in 2019 — and where people are unvaccinated, disease can spread. We’re seeing it happen right now as the Texas outbreak spreads beyond state lines. Given this, vaccine clinics (including mobile units that meet people where they are and make it easy to get vaccinated) are urgently needed.” Our lack of preparedness is striking. Sofi Papamarko, now in her forties, is a rare person to have gotten measles in the 1980s, but before a late resurgence in the disease that hit the United States, quickly infecting 55,622 Americans between 1989 and 1991. At the age of 14, then, Papamarko contracted measles from a spell at summer camp north of Toronto. No one thought much of the mysterious rash she came down with a week or two after returning home. So she attended a wedding and her brother’s graduation. Infographic chart showing weekly measles cases in the US since January 2023, according to the Centers for Disease Control and Prevention data. (Graphic by Janis LATVELS and Nicholas SHEARMAN / AFP via Getty Images) “We didn't know what it was until getting a letter from public health that said I may have been exposed to red measles from X date to X date at the name of the camp I attended,” Papamarko told Salon. "So it was pretty obvious at that point and when we went back to the doctor, he said I was a textbook case and he just had no idea because he'd never seen a case of measles in his entire career." In fact, while there must be many older survivors of childhood measles around, most people with expertise in the disease in North America would have been much older than the children of the '40s and '50s… meaning that there are virtually no doctors practicing exclusively in the United States who have direct experience with measles at all. They’ll all have plenty of experience giving MMR vaccines, though — and that’s the happy reason for their lack of measles recognition skills. “I'm lucky in that I didn't suffer any long-term ill effects,” Papamarko said. “But I also don't think we were at all knowledgeable about how potentially dangerous the illness is. The internet didn't exist back then and the doctors we saw were pretty uninformed about it.” So let’s talk about what happens after you send your kid to their measles party. The first dose of a measles vaccine is usually given after your baby is one year of age. So while you may have chosen to let your unvaccinated child get measles, you may be choosing for others as well, including families who have children too young to get vaccinated even if they desperately want the shot. It’s worth noting, if you live in an area with known outbreaks or if you are traveling with your baby, that the vaccine can be given as young as six months, so you should talk to your pediatrician about whether early vaccination might be wise. Some research suggests that it works but that its effectiveness, or perhaps effectiveness of some of the multiple ways in which children are protected following vaccination, may not last as long in kids who are vaccinated earlier than normal. Your eyes, your ears, your lungs Pneumonia is what most often sends a child with measles to hospital. One in 20 children with measles may get pneumonia, so the odds are high that someone at that measles party will get it. Pneumonia can be mild or it can be severe, and it can have long-term effects for a child, such as chronic lung disease, lung function deficits, and increased risk of adult asthma, chronic obstructive pulmonary disease unrelated to smoking, and bronchiectasis. And it can result in death: in fact, it’s the most common way measles kills young children. But it is far from the only threat. “Blindness is a very real threat to children with measles,” writes the American Academy of Ophthalmology. Measles was once the leading cause of childhood blindness, and there are several different ways in which it can harm vision. It can also cause temporary or partial but long-term vision loss. And retinitis, which can cause temporary or permanent vision loss during infection, can also appear years after the measles infection. You may have heard anti-vaccine claims that treatment with vitamin A is all you really need. This might come from official medical recommendations to provide a specific dose of vitamin A in cases of severe measles to reduce the risk of vision loss, which can be greater if the patient is malnourished or has a vitamin A deficiency. But a 2021 study, perhaps the first to look at whether there’s any reason to supplement vitamin A in young, hospitalized measles patients in higher-income countries where deficiency and malnutrition are less likely, found that it didn’t help reduce the risk of any complications of measles and it didn’t change the clinical course of the disease. Given that, and given the variety of risks measles infection poses for your sight, it would be far wiser not to get it in the first place. Vitamin A is also not effective at preventing measles infection, and it can be dangerous to take in large amounts. One in ten measles infections results in an ear infection, often accompanied by bacterial sepsis, and can result in hearing loss. Most children infected with measles are under the age of five. This coincides with the key developmental period for acquiring speech and language. As a result, of some 112 children with measles-induced hearing loss in one retrospective study, about 84% were not capable of speech. And your brain We’ve been here before, sort of. From 1989 to 1991, there was a resurgence of measles in the United States. During that time, 55,622 Americans came down with the disease. (For a variety of reasons, there used to be major disparities between vaccination rates of white vs non-white children, with rates 18% higher in white children in 1970. As a result, during that epidemic, non-white children were at four to seven times higher risk of infection and so at higher risk of long-term effects. Major targeted as well as universal policy initiatives were required to narrow that gap, and censoring words or banning concepts relating to race or ethnicity from epidemiological analyses and funding applications risks widening it again.) The 1989 to '91 resurgence unfortunately gave us an opportunity to remember the terrible pain measles causes to families and communities. Swelling of the brain, resulting in death or damage that could involve any part of it, is perhaps the most frightening thing that measles can do to your child. It can occur as part of the initial disease, it can be an immune reaction that occurs just afterwards, or it can occur years down the line. Famously, Olivia, the daughter of author Roald Dahl, died of encephalitis that occurred after she seemed to have almost recovered from a bout with the disease. He has written movingly of the way a bright and active child lost her faculties, becoming drowsy and then unable to do basic things: “I was sitting on her bed showing her how to fashion little animals out of colored pipe-cleaners, and when it came to her turn to make one herself, I noticed that her fingers and her mind were not working together and she couldn’t do anything.” Within an hour she was unconscious, and 12 hours later she was dead. Although Olivia died, other children may survive encephalitis, ending up with brain damage that can be severe or quite subtle, but life-changing for all that. “The person may seem like they function relatively normally, but they can really struggle with everyday activities,” Crowcroft explained to Salon. “I’m speaking to somebody who, for example, was still having trouble figuring out the order that you had to do things in. So she knew that to brush her teeth, you need a toothbrush and toothpaste and water, and you go to the bathroom, and you’d have the sequence of events. But she was having trouble figuring out what to do in what order.” Issues child survivors of measles can carry into adult life range from similar difficulties with executive function and organizing daily life to personality problems, aggression or complete inability to function. “It may be less obvious, but still it can change the trajectory of where their life is going to end up,” Crowcroft said. The worst long-term complication of measles is a form of delayed encephalitis called subacute sclerosing panencephalitis (SSPE). It’s a central nervous system disorder that only strikes seven to ten years after a measles infection, especially when the child was under two years old when they had that infection. It’s almost always fatal. “Often it’s hard to diagnose because it comes on as a progressive neurological problem,” Crowcroft explained. "A child who has seizures, has trouble walking, seems to be losing concentration, and no one’s really sure what’s going on, and it’s not until they do a spinal tap and find the evidence of measles infection in the cerebrospinal fluid that the diagnosis is made. So that can take some time because — well, again, it goes back to where we don’t have any measles around and everyone’s vaccinated and everyone’s forgotten about it.” So the child gets measles (perhaps at the local measles party), gets red spots, recovers … and after seven years or perhaps a decade of loving and caring for and living with that child, they begin to lose their faculties and, other than a small percentage of cases in which spontaneous remission occurs, the vast majority die in a particularly cruel way. Families may never recover from the suffering of watching their child die from SPPE. There seems to be no relationship between how bad the initial case of measles is and whether the child later gets SSPE, making survival and "being fine" afterwards a poor measure of whether that measles party is a good idea. And disturbingly, a 2017 California study suggests that SSPE is far more common than was previously believed. Of the cases reported following the measles resurgence that ended in 1991, one in every 609 children under the age of 12 months at the time they contracted measles eventually came down with SSPE. As the authors of that study conclude, “SSPE cases in California occurred at a high rate among unvaccinated children, particularly those infected during infancy … SSPE demonstrates the high human cost of 'natural' measles immunity.” There’s also an adult-onset form of the disease that is again usually fatal, although more spontaneous remission seems to occur, especially if the adult was unusually young when they contracted measles. Like other measles complications, SSPE cannot be caused by the MMR or measles vaccine. The health care system “Events promoting intentional exposure to measles, such as 'measles parties,' can overwhelm local public health and medical services while endangering the lives and health of many community members,” warned Dr. Theresa Chapple-McGruder, associate professor of health policy and management at the University of Pittsburgh School of Public Health. In an email interview with Salon, she noted that the extreme infectiousness and long infectious period of the disease means isolation periods are necessary and are very long: 21 days for someone who’s just been exposed to measles but who lacks immunity. The alternative is returning to the days when one in 4 children was hospitalized every year due to measles. Chapple-McGruder says that Americans have forgotten to celebrate successes, like the roughly 12,500 children’s lives saved in the past 25 years thanks to vaccination. The result: “Many have no frame of reference as to what measles can do to a child, family or community. We are seeing this firsthand with what is happening in Texas. I saw it firsthand during the Chicagoland measles outbreak of 2024,” Chapple-McGruder recalled. And then there’s another long-term effect of measles: it can wipe out your immune system’s memory, putting kids who’ve survived even a mild case at risk of far more frequent and severe cases of the entire Petri dish of infections in which kids are immersed at daycare and school by wiping out the antibodies they’ve previously acquired. All-cause mortality Perhaps it should be obvious that if more people get more infections because measles has caused their immune systems to lose their memory of the pathogens they need to fight, some proportion of that greater number of people will eventually get really sick. But even if you are aware of that, abstractly, it can be hard to really grasp the implications. So yet another long-term effect might come as a surprise: you’re more likely to die of infection — any infection — if you’ve previously had measles. Getting vaccinated has long been known to reduce the amount of other infections a child gets. But looking at mortality data, it looks like the immune system is significantly disabled against other infections for up to three and perhaps up to five years, a period in which your child is more likely to die. So once you’ve been to your measles party, it might be wise to hold off on that chicken pox party. Or any party, really. Or at least wear a mask. Mind you, there’s another possible reason for lowered child death rates among vaccinated children, and that’s if the measles vaccine gives your child some kind of protection that goes beyond its goal of preventing measles infection. This is called a non-specific beneficial effect. There’s significant evidence to support this: for example, a generally lowered death rate (what the experts call a child survival benefit) from measles vaccination even in places where measles doesn’t exist. And children who are vaccinated with the MMR vaccine are less likely to be hospitalized with any infection. This effect is stronger in kids who are vaccinated at younger ages. Who wouldn’t line up to get this child survival benefit for their kids?