A tragic reminder of the power of vaccination

In February, an unvaccinated child in Texas became the first to die of measles in the U.S. in a decade. The country’s most recent outbreak of the vaccine-preventable virus has resulted in more than 250 cases in the state since January. The same day this death was reported, I spoke with Adam Ratner, a pediatric infectious disease physician in New York City and the author of the new book Booster Shots: The Urgent Lessons of Measles and the Uncertain Future of Children’s Health.

Uncertain, indeed. Twenty-five years ago, the U.S. declared measles eliminated. Eliminating measles is not the same as eradicating it — smallpox is the only human virus ever to be eradicated globally. While measles eradication is possible, as Ratner suggests in his book, the effort is unlikely to garner the political or economic support required to achieve it anytime soon. Elimination, a much more achievable goal, requires stopping the sustained spread of the virus.

The U.S. measles elimination in 2000 was accompanied by worldwide progress in tackling the virus. By the late 1990s, global measles deaths had decreased by about 85%, according to Booster Shots. Simultaneously, global vaccination rates were up approximately 70%. By the time the U.S. declared measles eliminated in 2000, the entire Western Hemisphere was on the path to being measles-free.

But in recent years, these trends have reversed. The U.S. has faced a resurgence of measles, as well as other once ubiquitous, vaccine-preventable childhood diseases. Cases of pertussis (whooping cough) are on the rise, according to the U.S. Centers for Disease Control and Prevention (CDC), and other rare infectious diseases are popping up. In 2022, an intentionally unvaccinated young adult in New York was diagnosed with paralytic polio resulting from infection with the poliovirus. Wastewater testing in that region of the state, including New York City, suggested evidence of community spread. That same year, Ratner encountered his first patient with Hib, a disease caused by infection with Haemophilus influenzae type b bacteria, rates of which had decreased by 99% since the vaccines were introduced in 1987.

It is the recurring outbreaks of measles, however, that serve as the strongest harbinger of public sentiments toward vaccination, partly because the virus itself is so infectious that it quickly illuminates populations that are the most vulnerable.

One of the more extensive measles outbreaks in the U.S. occurred in 2014. That year the country amassed 667 measles cases, including a notable outbreak in California that started with a child at Disneyland and set off waves of infection among unvaccinated or under-vaccinated children (those who have not received the required two doses of the vaccine). That outbreak was deemed to be directly connected to the growing anti-vaccine movement in the country, and in California, in particular.

This movement, much like the virus itself, is spreading. In 2019, there was an explosion of cases linked to outbreaks in Orthodox Jewish communities in New York City and its nearby suburbs. These outbreaks were remarkable not only for their size but also their longevity and were attributed in part to many parents seeking religious exemptions from vaccinating their school-age children. By the end of that year, the U.S. recorded the highest number of measles cases since 1992. “We had taken vaccines for granted and were paying the price,” writes Ratner. Quite literally — curbing the 2019 outbreak cost the New York City Health Department alone more than US$8 million.

Global trends at that time were equally discouraging. In 2019, the global burden of measles was 9.8 million cases with 200,000 deaths — a 50% increase in deaths due to measles since 2016. “Measles, as always, was a bellwether, illuminating the challenges that we faced, the areas in need of attention, the holes in our defenses,” Ratner writes. “This time the message that it was sending was that we were losing ground in immunization delivery, trust, and public health.”

The World Health Organization even listed vaccine hesitancy as one of the top threats to global health in 2019.

Then came COVID-19.

COVID-19 vaccines were developed in record time and were incredibly effective at preventing death from SARS-CoV-2 infection. Yet the pandemic seemed to strengthen anti-vaccine sentiments. Disinformation related to vaccines reached a fever pitch, and this led to skepticism of doctors, public health authorities, and even science in general. “It was all there with measles, and it all fed directly into the issues that we faced during COVID-19 and continue to face today,” Ratner says. 

In 2024, there were 16 separate measles outbreaks in the U.S., racking up 285 cases of the vaccine-preventable disease, according to the CDC. Only two months into 2025, there are nearly as many cases already and two deaths.

“Given that we have had a safe and effective vaccine against measles for nearly sixty years, every single measles case that occurs in the world is a massive unforced error,” says Ratner. “Developing a vaccine is essential to solving the problem, but it isn’t sufficient. The vaccine has to make it into the arms of people who need it.”

Ratner and I spoke recently about the uncertain future of children’s health, how and why vaccine skepticism is spreading, and the idea of immunologic amnesia. What follows is an edited version of our conversation.

In your book, you outline two main reasons why parents may choose not to immunize their children. One is the fear of vaccines. For measles, you attribute this largely to the failure of doctors and public health experts to communicate effectively and some confusion when the vaccine was initially introduced. What are the most important lessons from the introduction of measles vaccines?

There are a few missteps that I wish we hadn’t made with the measles vaccine. The first issue is that two vaccines were licensed at the same time. One was like the Salk polio vaccine, a killed virus vaccine, and one was more like the Sabin polio vaccine, a live-attenuated virus vaccine, which is the predecessor to the measles vaccine we still use today. It’s completely reasonable that they were both introduced at the same time as they both looked safe and worked. The problem was that the live-attenuated vaccine that came out at that time was associated with a pretty significant fever, so you had to administer it with a low dose of gamma globulin, which meant it was two shots. That made the live-attenuated vaccine less appealing to parents.

Then there was the killed virus vaccine, which caused fewer side effects, but based on the data available at the time, it looked like this vaccine wouldn’t work as well as the live-attenuated vaccine. In the end, the killed virus vaccine didn’t end up working as well as the live-attenuated version, which is why we no longer use that type of measles vaccine now. But that initial introduction was confusing.

The second issue is that we, as a country, hadn’t figured out how to finance vaccines yet — there wasn’t a dedicated system to pay for these things. After the Salk polio trial, everyone wanted the polio vaccine for their kids, so the country had to figure out how to make that happen both logistically and financially. To address this, the government outsourced the production of polio vaccines to a bunch of different companies, which, in one case, ended up leading to the Cutter incident. The March of Dimes ended up paying for some of the rollout, and then U.S. President Eisenhower agreed to provide federal funding for the distribution of polio vaccine, but that was solely dedicated to polio. There still wasn’t a federal plan to pay for future vaccines, including measles. The live-attenuated measles vaccine would have cost about $10 a dose then, which is like $100 a dose today, and so it was out of reach for a lot of families, particularly those who were more likely to have kids with severe measles because it’s always poor and less well-nourished kids and those who live in more crowded spaces who suffer more.

Altogether, it was a logistical and financial nightmare, and we had a lot of lessons to learn in a short time.

Another factor at play is the minimization of the dangers of the viruses these vaccines are designed to protect against. As you say in the book: “Vaccines are masters of making nothing happen.” As a result, people forget how terrible some of these childhood diseases were. But with repeat outbreaks of measles and having just gone through the COVID-19 pandemic, why do scientists and physicians still have to convince the public of the benefits of vaccination?

This is mind-boggling to me. In my book I talk about when I got my first dose of the COVID-19 vaccine and how I felt this incredible sense of relief. My wife is also a physician and we’d both been working in COVID wards. It was really frightening, so when the vaccines were available, and my wife, daughter, and I had all been vaccinated, I felt this enormous sense of relief that we were going to get out of this and that vaccines were what was going to save us. I thought that people were going to have seen a pandemic and millions of people dying and then see vaccines developed and then, as a result, millions of people not dying anymore. This is exactly what happened. But then I thought this would be a fatal blow to the anti-vaccine movement, and that didn’t happen. It is still hard for me to wrap my head around that.

Some of it, of course, is a loss of trust in public health voices. I think public health officials, both those who were providing medical care and those in charge of public health agencies during the pandemic, were absolutely doing the best they could at every point. We had limited information, and things were changing over time, and as a collective, we were not always great at communicating that uncertainty. When the vaccines came out, we all felt, to some extent, this incredible relief, and the data for short-term protection against acquisition and long-lasting protection against death and severe disease looked incredibly promising. But we didn’t have years of data so none of us could have predicted that you’d need booster shots to enhance protection or say with certainty how many or what types of boosters you’d need. We didn’t have that information. But, again, I don’t think we communicated that uncertainty effectively in some cases, and in other cases, we did communicate it effectively and it just wasn’t heard.

The lessons that a big chunk of the population took away from the pandemic were never to shut down schools again, never to do masking again, and never to have any kind of restrictions. That’s the wrong lesson. There were millions of people dying, and though the response wasn’t perfect by any stretch, we did a good job. Still, that’s where in 2025 the bulk of the anti-vaccine sentiment lives.

There is also a growing anti-science sentiment, which seems hard to counteract because it is based on emotional arguments, not facts or figures, as you discuss in the book.

I think it is linked to emotions but my feelings on this have changed a bit. I think it’s actually an identity argument. There was a recent book called What We’ve Become: Living and Dying in a Country of Arms by Jonathan M. Metzl, which is about gun policy. It’s a wonderful book; not a happy read, as you might imagine, but he’s a public-health-focused person who believes in stricter gun laws and gun control. He’s also a psychiatrist who wants to understand why people make the decisions they make. At the end of the book he talks about having this public health lens on things and that what he realized over the course of talking to people on both extremes of the argument over guns is that doing another study that shows that gun laws decrease the number of dead children is not going to move the needle because one side is talking about statistics, while the other side is talking about identity. And I think that is true for vaccines too.

Let’s switch to something that is, ironically, much easier to understand: the immunology of measles. You detail how the measles virus preferentially attacks memory B cells from prior infections or vaccinations, resulting in what is called “immune amnesia.” This is one of the ways that measles infection is so problematic and why vaccination has much broader health implications.

It is the most interesting thing I know about measles.

How does it work and what are the consequences?

The virus infects immune system cells that express the SLAM [signaling lymphocyte activation molecule] receptor on their surface. These cells hitch a ride to lymph nodes and there the virus encounters other SLAM-expressing cells, including dendritic cells. But some of the most important SLAM-expressing cells are memory B and T cells, and these get wiped out by the measles virus. It is sort of analogous to how HIV uses CD4 to infect cells and so you get a depletion of CD4-expressing T cells, wiping out a critical part of the immune system. But in this case, it’s immune memory that is depleted — the cells that the body has stored away based on prior infections or vaccinations. As a result, measles leaves us vulnerable to other infections even after the virus itself is gone. Immune amnesia doesn’t happen to kids who are vaccinated against measles, so the vaccine not only protects kids against measles, but preserves their defenses against many other infectious diseases as well.

You say in the book that you are an optimist by nature. How do you maintain that optimism?

Well, I finished the book a year ago and I think it’s harder to be optimistic now then it was then, but we must be because we have to maintain some agency.

I did a book event this past weekend and a wonderful public health student stood up to ask a question at the end. His question was how students going into public health or pediatrics can maintain faith in what they’re doing. And the answer is it’s hard, but you have to. I am lucky in that a piece of my career involves being in the hospital and taking care of children. When other things are bad, when I can’t get research grants, or when the political system is breaking, I can go into the hospital and see patients, and I can feel like for that patient, right then, I’m doing something that matters. But it’s hard. We’re in a very different place than we were just a year ago, just in terms of thinking about what it’s feasible to do. It’s almost not a fair fight because it’s so easy to spread disinformation that you either drown out the good information or just make the information confusing enough to raise questions. 

It is still technically feasible to eradicate measles, but I think it will be a long time before that occurs. What I learned from the measles outbreak in New York City in 2019 shares a lot of factors with the one that’s happening now in West Texas. The religion and the geography are different, but there are many recurring themes. The thing that I learned here is that the outbreaks start in communities that have a deep distrust of public health for reasons that started out having nothing to do with vaccines. But this distrust makes communities much more susceptible to anti-vaccine ideas, and this makes it much harder in the thick of a measles outbreak for public health officials to do their jobs. I think the thing that helped here was the work of small groups of people in the community who were spreading the word door-to-door and organizing locally. That’s really important. It’s hard to replicate but is critical.