The risk you see, and the risk you don't

Like many people, I am worried and horrified by the recent outbreaks of measles around the country. There are more than 300 known cases of a disease that was considered eliminated in the United States. One child has died, and one adult died while infected with measles. These are the first deaths from measles in the United States in a decade.

Now, of course, many of the previously vaccine nervous parents are racing to immunize their kids, as they should. Adults are worrying if they need a booster. Meanwhile, places like Facebook are erupting with a rash of discourse.

Some people are blaming parents of those who choose not to vaccinate. But other parents are still full of fear. On one page, a man from my high school linked to a subheaded, 9 page document wherein he had piles of links.* Are the vaccines safe? Are they effective? Who’s accountable if my child is injured? What’s the “ugly” history of vaccine mistakes? It concentrated heavily on measles.

Before I get into this, I will declare my own bias: I have a Ph.D. in physiology and pharmacology, and was a neuroscientist. I have received all the vaccines I need and more. I in fact volunteered for the COVID vaccine trials (I didn’t get in), and for a Lyme Disease vaccine trial (I did get in, I received five shots, though I don’t know what I received. I look forward to being unblinded soon). I have studied the history and philosophy of science. Science is done by humans, and humans are pretty terrible. So I acknowledge it has problems. But I also think it is one of the only ways we develop life-saving medications. And I personally think vaccines are a triumph of human medicine. Many journalists believe firmly that our job is to cover both sides and avoid any appearance of bias. I think, much like scientists, journalists are human. We’re going to have bias whether we declare it or not. So I’m putting mine up front, so you can see where I’m coming from. That’s my side. I am trying to see his.

I wonder, a lot, what makes people distrust science. Not just what makes them nervous, but what makes them scoff, what makes them wave concerns off and declare everything will be fine.

So I went through the links he’d gathered with curiosity. Some were to actual scientific publications, others linked to deeply questionable sources like Mercola. There was a section called “follow the money” which mostly noted that vaccines are developed by pharmaceutical companies. His tone (studies are called “studies” with scare quotes when they promote vaccine benefits, and do not receive scare quotes when they note harms) betrays some pretty obvious bias on his own part.

The most detailed section was on safety. He’s a parent (I think), and so it’s no wonder that his biggest concern and the focus of his research so far was on the potential danger to his child. He was worried about the very existence of the Vaccine Adverse Event Reporting System. After all, why would there be a system if the vaccines were safe? (94.5 percent of adverse events reported for all vaccines are not serious, things like a red injection site, fever, etc.). He’s worried about cancer, about autism**, about behavioral disorders of every kind.

But one subhead, I noticed, was curiously incomplete. It was the section titled “what are the true risks of catching each disease.” There was one link, noting that no one dies of measles anymore, and even if they did, the death rate is low! But what’s the risk of dying of the MMR vaccine itself?, he asks.

And this is the issue I see most often with those who question vaccines. They are weighing (sometimes, as in this case, very deeply), two different risks.

And one of those risks is wrong.

What are the risks to weigh?

People like this person are weighing the risk of vaccine injury against the risk of nothing. Yes, vaccines are not perfect. Nothing is. Some cause side effects (I should know, I have received a lot of them). Everyone is different, every immune system is different (for a great intro to the banana-pants bizarro world that is the immune system I highly recommend the book Immune), and so yes, for a very few people, there might be side effects that are more serious.

For MMR, the highest risk is for febrile seizures, when a child’s fever is so high they have a seizure. They are scary, but temporary, mostly benign, and more common than you might think (2-5% of children will have them for pretty much any reason). The risk associated with the vaccine is four out of every 10,000, or 0.04 percent for one type of vaccine, and 1 out of 3,000 or 4,000 in another, or 0.3 percent.

But people are weighing this real risk against the risk of nothing. They are making an assumption that if they do not vaccinate their child, the alternative is that nothing will happen. That their child will never get measles.

This is the wrong risk comparison. The correct comparison is the risk of the vaccine, vs the risk of suffering from the measles.

They are making this incorrect risk comparison because, until very recently, it would not have harmed them. It would have been an intellectually wrong risk comparison, but practically, it wouldn’t have mattered so much. Because more than 95 percent of the population was vaccinated, herd immunity would have protected these parents and their kids. They never would have had a case in their county. The risk of their child contracting, let alone dying from, measles was a distant theoretical. The many loud articles filling their feed claiming “adverse events” from the vaccines feel far more real.

But now, herd immunity is decreasing. As more and more parents like this one fear vaccines and put them off or avoid them all together, overall rates fall. 25 states have below 95% vaccination rates, and 14 have below 90%.

Now, there are hundreds of cases in Texas. There are cases in Maryland. Cases flying through airports. Comparing the wrong risks is going to catch up to people.

It’s time to fill in that empty section.

I’m sure this is going to get some flak.

Measles

Measles is one of the most contagious viruses on the planet. One sick person in a room of unvaccinated people will infect 90 percent of those people. You are contagious for days before you show symptoms. It can linger in the air for hours. If you’re not vaccinated, and come into contact with measles? Don’t fool yourself you are somehow better. You’ll get it.

• The death rate for unvaccinated people is between 1 and 3 per 1000, which is roughly 0.2%. That is low. But if it is your child? That is far, far too high.

Another important risk, and the one people most often discount, is this: What risk does measles itself pose as a disease?

• 20 percent (one in five) of people who get measles end up hospitalized.

• One out of every 20 children (5%) will get pneumonia (this is the most common reason children die of measles).

• One out of every 1000 will suffer from brain swelling that can leave the child with hearing loss or intellectual differences.

• Pregnant women who get measles can suffer premature birth.

• Measles itself can cause immune amnesia, erasing the immune system’s memory of previous threats, which means someone who has had measles is much more likely to get sick from other causes. You don’t just suffer risks from measles, but from measles and the diseases you catch after it, diseases you wouldn’t have caught before.

Before the measles vaccine campaign began, there were around half a million cases of measles every year. Hundreds of children died each year. The vaccine has prevented 21.1 million deaths.

Weigh the risks, as any good parent does.

But make sure you weigh the right ones.

Sources:

1. Tiwari A, Meshram RJ, Kumar Singh R. Febrile Seizures in Children: A Review. Cureus. 2022 Nov 14;14(11):e31509. doi: 10.7759/cureus.31509. PMID: 36540525; PMCID: PMC9754740.

2. Azarpanah H, Farhadloo M, Vahidov R, Pilote L. Vaccine hesitancy: evidence from an adverse events following immunization database, and the role of cognitive biases. BMC Public Health. 2021 Sep 16;21(1):1686. doi: 10.1186/s12889-021-11745-1. PMID: 34530804; PMCID: PMC8444164.

3. Saey, T. What experts say about childhood vaccines amid the Texas measles outbreak. Science News, February 28, 2025.

4. Sanders, L. New details on immune system ‘amnesia’ show how measles causes long-term damage. Science News, October 31, 2019.

5. CDC. Measles Symptoms and Complications. Updated May 9, 2024.

6. Cleveland Clinic. Measles (Rubeola). Updated February 28, 2025.

7. Williams, E., Kates, J. Childhood Vaccination Rates Continue to Decline as Trump Heads for a Second Term. KFF Health News, November 18, 2024.

8. CDC. Measles, Mumps, Rubella (MMR) Vaccine Safety. Updated July 31, 2024.

9. Shastri, D., Seitz, A. A Texas child who was not vaccinated has died of measles, a first for the US in a decade. The Associated Press, February 26, 2025.

10. Godoy, M. With measles in the news, adults are wondering, do I need a vaccine booster? NPR, February 21, 2025.

11. Schreiber, M. Texas cities run short of MMR vaccine as measles outbreak drives demand. The Guardian, March 8, 2025.

Where have you been?

• Maybe it’s reading about this wonderful man. A man with an antibody in his blood that could save babies, and so he donated his blood, over and over and over, more than 1,000 times, never taking a single penny for it. He saved the lives of 2.4 million babies. This man? This man was a helper.

• Read about the woolly mouse? I’ve got THOUGHTS. So do many other excellent science journalists (like Sab Imbler here), and we all agree. This? Was a PR stunt that put a mouse in a genetic hamster outfit.

• A duck has been nesting in a planter just a few blocks from the White House. A guy who’s been checking in on her every day calls her Mallardy.

• Pet cats are, veterinarily speaking, still something of a black box. For a long time, people focused on dogs as a default.

• When your lover might eat you if you have sex, what’s a male blue-lined octopus to do? Poison her of course! Temporarily. Love is a battlefield.

• I am unshocked to find that wildlife are appearing in rehab facilities around the DC area with rat poison in their systems. In NYC, it’s 100% of wildlife studied, so DC’s 85% is sad, but not surprising.

• Many federal workers are facing fear and uncertainty, they’ve lost their jobs. And their families? Totally fine with it.

• NYC MAY be gaining ground in the war on rats! The reason? TRASH CANS.

• Ah yes, wasteful government spending. Good thing we don’t need to waste any more money hunting for a link between vaccines and autism, because there’s loads of evidence that vaccines don’t cause autism! So…yes…of course the government wants to study that. Again.

• In a truly amazing bout of symbolism, watch this lone Canada goose stave off a bald eagle. The eagle truly has regrets.

Where have I been?

• I mentioned in my last newsletter that I’d been on Freakonomics, in their first episode on the rat! Well they did three episodes and I was in the third one too. I talked about the origin of the lab mouse (and eventually the origin of the lab rat), and how these animals became useful to science in part because people never liked them!

• And I went to the Stand up for Science Rally in Washington, DC, to document the event! I got some pictures of some AMAZING signs…and one of them ended up in Rachel Maddow’s coverage. So that was exciting.

• And hey you can buy my book. It’s got a real human reading the audiobook and everything.

*This guy is an example, his concerns are real, and his feelings are real. I’m not going to link to or identify him personally. He’s just a very good (and exceptionally thorough) example of people who question vaccines, and the kind of information they rely on.

**People with autism are human beings. Saying that you feel the potential of your child becoming like them is a horror is a really awful thing to say.