Are there two sides in the vaccine debate?

Headline from a debate about vaccine hesitancy,

from December 2020.

I keep getting into debates with people about the safety and efficacy of vaccines. I’m not talking about anti-vaxxers (though I’ve encountered plenty of them), but level-headed, rational people who genuinely have doubts.

Usually their doubts about vaccines come from dubious sources, but there’s so much misinformation out there, often coming from people with the letters M.D. or Ph.D. after their names, that I can understand why it’s confusing.

So let me engage in what is sometimes called “both-sides-ism” (a disparaging term, of course) and consider, briefly, the pluses and minuses of vaccines. While I’m at it, I’ll include some points specific to the Covid-19 vaccines.

Let’s start with the pluses, shall we?

1. Vaccines are the single greatest public health innovation in the history of medicine. They’ve saved millions of lives.
2. Vaccines completely eliminated smallpox from the planet. They have nearly (but not quite, due to anti-vax resistance) eliminated polio.
3. The new mRNA vaccines for Covid-19 are remarkably effective, have very few side effects, and are easy to modify as the virus itself mutates over time.
4. Vaccines protect us so thoroughly against childhood infections that many formerly common infections–including measles, mumps, and Haemophilus influenza–have almost disappeared.
5. Child mortality from infectious has plummeted in countries with robust early childhood vaccine programs.
6. The vaccine against human papillomavirus (HPV) will prevent many thousands of cases of cervical cancer, throat cancer, and other cancers, saving lives for decades to come.
7. Vaccines train our immune system to recognize and fight off infections, in many cases stopping the infection before we even have symptoms.

I could go on, but the bottom line is that vaccines continue to save millions of lives every year. They also dramatically reduce non-fatal illnesses, sparing people a great deal of suffering as well as long-term harms caused by some infections. (For example, mumps can cause permanent hearing loss.)

Given all of these benefits, you might wonder why everyone doesn’t get every vaccine available. Well, some people do, and part of the answer is simply that we don’t have enough vaccines for everyone, and many countries lack the public health infrastructure to deliver vaccines. But there are a few very small minuses, so let’s consider the downsides of vaccines:

1. The shot (or “jab”) hurts a little bit, and your arm might be sore for a day.
2. In very rare cases with some vaccines, some people might have allergic reactions. One example is that some flu vaccines are manufactured in chicken eggs, and people with egg allergies might react to those.
3. In a few rare cases, the live polio virus vaccine has caused some people to get polio. This vaccine was discontinued in the U.S. decades ago.
4. In rare cases, some people might have an immune response to a vaccine that causes ongoing inflammation. This includes the Covid-19 vaccine. However, the risk is much smaller than the risks associated with an actual infection.

That’s pretty much it. I hope it’s clear that the pluses far outweigh the minuses, but I imagine that some people looking at this list are wondering why I didn’t include a host of other supposed harms of vaccines, such as an increased risk of autism.

That’s because vaccines don’t cause autism or any other neurological disorder, as I’ve written before. Studies involving hundreds of thousands of people have been done to investigate this possibility, starting in the early 2000s, and all of the science points the same way: vaccines do not cause autism.

This supposed risk, and others like it, are inventions of the modern anti-vaccine movement. I won’t go into the history of the anti-vax movement here (I’ve done that before, many times), except to point out that many people promoting anti-vax misinformation are making lots of money selling “cures” for problems that don’t exist in the first place.

Anti-vaxxers continue to invent new harms caused by vaccines, and spread these claims on social media. Even with no evidence whatsoever, some of these claims catch on, because - well, the Internet.

Now back to the title of this column: are there really two sides to the vaccine debate?

Well, no.

Among doctors, scientists, and public health professionals, virtually everyone agrees with my first point in the “pluses” list above. However, we all recognize that when a foreign substance (a vaccine) is injected into one’s body, it’s possible that something unexpected might happen, and we must continually monitor vaccines so that we’ll know if something goes awry.

Let me end with an analogy. Seat belts in cars have been around for decades, and they’ve prevented millions of injuries and deaths. And yet people have argued (and probably still do) that it’s possible that wearing a seat belt might cause harm, for example if the belt jams and one cannot escape a burning car after an accident. (This seems to happen all too often in movies.) Thus you can’t argue that wearing a seat belt is 100% risk-free. Even so, wearing a seat belt is a really good idea, because the benefits are so much greater than the risks.

The same is true of vaccines. There might be some very, very small risks, but the benefits vastly outweigh them. And modern vaccines are safer than ever. There’s no serious debate about that.

Do telomeres measure our true biological age, and can we do anything to maintain them?

Telomeres are one of the keys to aging. We’ve known this for decades, and the scientists who first figured it out won the Nobel Prize in 2009. (One of them was my former colleague at Johns Hopkins University, Carol Greider.) Not surprisingly, many people have been trying, ever since, to use this discovery to slow down or reverse the aging process.

No luck so far, but that doesn’t mean you can’t spend money on your telomeres.

Over the past decade or so, a number of companies have started offering to measure your telomere length, which they suggest will tell your true, biological age. Sometimes, along with these measurements, they will offer to sell you something that they claim maintains or even lengthens your telomeres, thereby making you younger. What’s all the fuss?

Well, let’s start by explaining what telomeres are. Every cell in your body contains your DNA, arranged into 23 pairs of chromosomes. (That’s the origin of the company name for 23andMe, by the way.) Your chromosomes are very long strings of DNA letters (usually written A, C, G, and T). Through a quirk of biology, the very tips of our chromosomes are special: they contain thousands of copies, repeated end-to-end, of the 6-letter sequence TTAGGG. These are the telomeres, and they are a common feature in all animals, plants, and pretty much every living thing except for some single-celled microbes.

What’s fascinating about telomeres is that they provide a molecular “clock” that you can use to tell how old a cell is–sort of. You see, each time your cells divide, they have to copy all of that DNA, and sometimes they don’t quite copy the entire telomere. Over time, your telomeres get shorter.

This means that, in theory at least, your telomere length can tell you something about your age.

When humans are still infants, our telomeres are about 10,000 DNA letters long, and they slowly get shorter. By the time we’re in our 80s and 90s, our telomeres might be only 4000-5000 letters long–but this varies enormously. Telomere length varies from tissue to tissue–even your blood has many different types of cells in it, with different telomere lengths–and from person to person. Thus it’s entirely possible for a healthy 40-year-old to have telomere lengths that are typical of 80-year-olds, and vice versa. Here’s a graph from a scientific study that looked at telomeres in over 800 people, showing how they get shorter as you age. Length is on the vertical axis, measured in thousands, versus age on the horizontal axis:

Part of Figure 1 from “Collapse of telomere homeostasis in hematopoietic cells caused by heterozygous mutations in telomerase genes, G Aubert, GM Baerlocher, I Vulto, SS Poon, & Lansdorp, PLoS Genetics, 2012. © 2012 Aubert et al. This is an open-acce

AUBERT G, BAERLOCHER GM, VULTO I, POON SS, LANSDORP PM (2012) COLLAPSE OF TELOMERE HOMEOSTASIS IN HEMATOPOIETIC CELLS CAUSED BY HETEROZYGOUS MUTATIONS IN TELOMERASE GENES. PLOS GENET 8(5): E1002696.

As you can see, telomeres decline from about 10,000 letters (bases) at birth to about 5,000 in 80-year-olds, but many people have telomeres that are thousands of bases shorter or longer than the average.

When its telomeres get too short, a cell will die. So the reasoning goes, if we can keep our telomeres nice and long, we’ll live longer! It might seem simple, but it’s not.

First, it’s not clear that there’s anything we can do if we know the length of our telomeres. As my Hopkins colleagues Mary Armanios explained, “Within the normal telomere length range, it is not possible to determine a person’s exact biologic age, nor is it a good marker of a person’s ‘youthfulness.’”

The other problem is that it’s not clear that we can take any action to make our telomeres longer, or even to prevent them from getting shorter. But there are a couple of things you can try:

Exercise regularly. There is some evidence that regular exercise is correlated with longer telomeres. A study in 2017 concluded that “adults who participate in high levels of physical activity tend to have longer telomeres, accounting for years of reduced cellular aging compared to their more sedentary counterparts.”

Avoid stress. Another study in 2016 found that stress tended to make telomeres shorter.

Even if both of those studies are wrong about telomeres, the general advice to exercise and avoid stress is good for all sorts of reasons, so I’m happy to endorse these recommendations.

In addition, there are companies (like this one) that claim you can take supplements that will maintain telomere length, but I couldn’t find any solid evidence to back up those claims. So no, you can’t take a supplement or a pill that will restore your telomeres to the lengths they had when you were a baby.

Finally, there is some promising early research that uses mRNA technology–the same technology used to develop the new COVID vaccines–to deliver enzymes that rapidly increase telomere length in human cells. A huge caveat is that this only works in cells growing in a laboratory culture, and no one knows if it’s possible to do this in a living human. But it isn’t a crazy idea, so I’ll keep an eye on this research.

So what about companies that offer to measure your telomere length? Well, they really can do it, although the accuracy of various technologies will vary. Given what we know today, it seems unlikely that these tests will provide anything of value, unless you’re among a very small cohort of people who have a telomere-related genetic disorder. So my advice is, don’t waste your money. But it can’t hurt to exercise regularly and avoid stress, and both of these pieces of advice might help maintain your telomeres as well.