A Thought Experiment on Herd Immunity

You may have heard of the concept of “herd immunity.” I am not referring to anything having to do with groups of large, hoofed animals, although I suspect the concepts would apply to them as well. What this refers to is the resistance of a population to a disease.

Let’s consider a highly-contagious, fictional disease by the name of Sauderosis. Assume we have a vaccine for Sauderosis which is effective in preventing the disease in 90% of the people who are vaccinated and subsequently exposed to the disease.

Imagine a school with one hundred students who have all been vaccinated against Sauderosis. Since the vaccine is 90% effective, ten of the students in the school will be susceptible to Sauderosis if they are exposed. If there are 20 students in each class, that means two students in each class who are susceptible, so there is not likely to be a widespread problem with the illness in the school, even if someone comes to school sick with the disease.

Now consider that same school if only 50% of the students are immunized against Sauderosis. There are now 55 unprotected students in the school, all 50 who were not vaccinated and five who were (10% of the 50 immunized students). That would mean there are, on average, 11 students in each class who are susceptible so there is a significant chance of a large outbreak if the illness is introduced to the school.

Now imagine your child has an underlying medical condition which makes him more likely to have complications of Sauderosis. If he gets this illness, he is likely to end up in the hospital and may even have life-threatening complications. Which school population would you want him to be in?

Random Thoughts While Running

This is another blog post that really doesn’t have anything to do with pediatrics but for some reason was what I was thinking about while running today.

A few months ago, one of our vehicles had a flat tire. For a variety of reasons that I won’t bore you with (in part because I can’t remember them), the only time I had to change the tire was late on a Saturday afternoon. But when I went to take off the flat tire, one of the lug nuts was stripped and the wrench just kept slipping off. I really couldn’t figure out what to do and knew we needed to have the vehicle available Monday morning.

I texted a friend for advice and called around until I found one tire place in town which was open for another 30 minutes. I pumped up the tire with the bicycle tire pump, threw the pump in the back, and headed to town hoping for the best.

After I arrived safely, it took them about ten minutes to remove a nail, patch the tire, and get it pumped up again for me. We chatted about college football while they were doing it and I was ready to leave in no time. When I went to pay, the charge was $10. Forty-five minutes earlier I had been in a panic trying to figure out what to do and these guys saved me. I told them to charge me more but they insisted $10 was the charge.

That made me think about how we determine the value of things. The guys who fixed my tire possess equipment and knowledge to know how to patch a tire. That is a valuable thing to a guy like me who does not know how to do it himself.

We all have our own niche and expertise and need to value that in each other. When I have a patient who needs more help than I can provide, I refer them to a doctor who specializes in the problem they have. When an oak tree fell on our garage roof, I called guys who could remove it safely. If I want to understand a scientific issue, I read things written by the scientists who work on it. If I have a problem with the house, I call a contractor. When my snowblower quit working, I called folks who know how to fix snowblowers. If I don’t know which E&M code to use for a visit, I ask our office manager.

We all depend on each other for different things. I know some really handy and talented people but I don’t know anyone who can get through life all on their own. At the risk of sounding preachy, it reminds me of I Corinthians 12:14 and following which talks about the need for every part of the body to do its job for the body to function properly.

So look for the value in others and acknowledge it. It will make their day and it will help you appreciate them more.

What's the Deal with Artificial Sweeteners?

One topic which seems to be talked about a lot without much definitive data is the effect of artificial sweeteners.

There are six low-calorie, artificial sweeteners approved by the FDA – saccharin (Sweet’N Low), aspartame (Nutrasweet), Ace-K, sucralose (Splenda), neotame, and advantame. These compounds work by stimulating human sweet-taste receptors while providing minimal to no calories. They are excreted unchanged from the body so have been considered to have no direct physiologic effect.

However, there have been concerns about indirect effects such as alteration of the gut microbiome (the bacteria living in the intestinal tract) and the dissociation of sweetness from calories. It is hypothesized that these alterations could result in changes in the way our bodies process nutrients and govern our sense of hunger and satiety.

There are studies which have shown weight controls benefits when drinking beverages with artificial sweeteners instead of sugar. Other studies suggest that artificial sweeteners may actually increase the risk of weight gain and type 2 diabetes. Results differ depending on the study group and it is difficult to tell how the results in one study group apply or do not apply to groups with other characteristics.

So it is difficult to draw any definite conclusions. But there are two things I know for sure on this topic. Drinking sweet drinks such as soda, sweet tea, and sports drinks add a lot of unnecessary calories. A 16 ounce soda has around 250 calories in it. To burn that many calories, one would need to walk or run approximately two miles. It is much easier to skip the soda than to add two extra miles to your daily workout. The second thing I know for sure is that water has no calories and is great at quenching thirst.

So next time, reach for the water instead (assuming your water source is clean and free of harmful substances which is another topic for another day).

Vaccines 101

Some things I have heard and read lately make me think we have been so busy debunking spurious claims about vaccine side effects that we have not been doing a very good job of educating people about basic vaccine facts, how they work, and why we give them.

Vaccines incorporate microorganisms (bacteria and viruses) or pieces of microorganisms which are given orally or through a shot. If a whole virus is used, it is “attenuated” (weakened) so it does not produce illness. The recipient’s immune system mounts a response to the weakened germ or pieces of germs in the vaccine so that when it encounters the real thing, it has a response in place to fight it off before it can produce illness.

In 1921, there were over 200,000 cases of diphtheria in the United States and over 15,000 deaths from it. I do not know any doctors who have ever seen a case of diphtheria, though it is still present in some parts of the world. What was previously a feared and deadly illness was eradicated from the United States in the 20^th century.

When I was a child, I remember asking my father once about why a man was limping and had a leg that did not seem to be formed quite right. My father’s reply was that the man had had polio as a child. I have never seen a case of polio and probably (hopefully) never will. Vaccine campaigns have eliminated it from everywhere in the world except a couple of pockets in Africa and the middle east and the hope is that total eradication is not far off.

Smallpox is another disease I have never seen and we do not even immunize against it anymore because it has been eradicated from the entire globe through immunization. The last known case was in 1977.

A now-retired colleague of mine used to talk about how common Haemophilus meningitis used to be and how it was something that kept pediatricians awake at night worrying that they could have missed a case in a child who appeared to have a more benign illness. I have only ever seen one case of Haemophilus meningitis and that was with a strain not included in the vaccine which was introduced in the mid 1980s. This same germ can also cause a condition called epiglottitis. The memories of children being strangled by their own swollen airways led the older pediatricians who trained me to spend a significant amount of time teaching about this. Fortunately, having graduated from medical school in 1993, I have never seen a case of epiglottitis.

The measles vaccine was also introduced prior to my medical training and I have never seen a case of measles. However, recent outbreaks in under-vaccinated parts of the United States are a warning to us not to become complacent about immunizing.

I have also seen the effects of the introduction of new vaccines during my career. When I was a resident physician, it was not unusual for us to care for children hospitalized with complications of chicken pox. Most people do not realize that prior to the introduction of the vaccine, about 100 children in the United States died each year from complications of the disease. Now I can’t even remember the last time I saw a child with chicken pox.

Similarly, the Rotavirus vaccine was introduced since I have been in practice. We used to see a lot of this illness in the winter time and often had children admitted to the hospital for dehydration resulting from it. But it has basically disappeared since the introduction of the vaccine.

So it is important to remember that we do not give vaccines just for something to do. They are given to prevent real diseases, with real consequences, in real people.

 

Hand, Foot, and Mouth Disease

Over the past month or so, we have seen a lot of cases of hand, foot, and mouth disease. This disease is generally benign but seems to cause a lot of concern, especially if affected children are in daycare or a school situation.

Typically we see children with some sores in and around the mouth and small blisters on the palms and soles. There are variations in presentation and sometimes children will have rash on other parts of their body as well. The buttocks are another common place for the rash. Fever is sometimes present and sometimes not.

If there is pain from the mouth lesions or fever, acetaminophen or ibuprofen can be used to make children more comfortable. There are no medications available which shorten the duration of the illness and most affected children have minimal discomfort.

The viruses which cause hand, foot, and mouth disease can also infect children without causing any symptoms at all. When symptoms do develop, children are contagious from before the rash starts and continuing for several weeks thereafter.

Because the contagious period lasts so long and there are likely to be other infected children in the class who have no symptoms, exclusion from daycare or school is generally not recommended because it is unlikely to have any effect on the spread of the disease.

So if your child has hand, foot, and mouth disease, there is no cause for alarm and he should get back to normal fairly soon without causing any undue risk to his classmates.

Yes, Your Epipen is Expensive but...

Many of you have probably heard about the increase in EpiPen prices recently. An EpiPen is a device that can be used to deliver a dose of epinephrine (adrenaline) to a person having a serious allergic reaction to keep things in check until emergency medical attention can be accessed. Many people with food allergies, allergies to bee stings, etc. carry these with them and they can potentially be life-saving.

As I understand the situation, the price has risen as one company has developed a virtual monopoly on the product. Essentially, this is the free market at work. There is a lot of demand and one company has the supply with little competition so the price has gone up. In addition, more people now have insurance plans with high deductibles and co-pays so patients are seeing more of that cost themselves than they used to. This has led to a lot of publicity about the high cost of this commonly-prescribed medication. One could argue about whose fault that is and how it should be fixed.

This got me to thinking about people in similar situations with less commonly used treatments. There are patients who pay thousands of dollars a year out-of-pocket for treatment for disorders which most people have never heard of. They would be delighted to have the $600-a-year problem of EpiPen users. But since their disorders are uncommon and not many people use the medications they use, there is not a large group of patients to catch the ear of politicians and the media. And the treatments are often not covered by insurance at all.

So they end up paying large sums for treatments that are almost certainly not that expensive to make and are just as important to treat their disorders as an EpiPen is for a person with a serious allergy. I don’t know the answer to the problem, but I think it is important for people to know it exists.

Some Thoughts on Youth Sports

While watching our youngest son, Jacob, play soccer last spring, one of the other fathers asked me “Do you think sports teach life lessons or do you think we overdo it?” I replied “Yes.”

I have loved sports for as long as I can remember. As a child I could spend hours by myself playing make-believe sporting events or sorting my baseball cards. And I played hours of driveway basketball with friends or baseball in the pasture across the road from my best friend’s house. We would use major league line-ups and bat the way the actual players batted. That’s why as a natural left-handed hitter, I usually chose Mike Easler over Bill Robinson to play left field in my version of the late 1970s Pirates. It got me another left-handed bat in the line-up.

As I got older, I discovered soccer and ended up being pretty good at it and played both soccer and baseball in college. My wife, Cindy, played college volleyball. So when we had children, I naturally started playing all kinds of ball with them. We ended up involved in youth and high school sports from the recreational to “elite” levels and everything in between. This has included swimming, baseball, football, basketball, volleyball, and soccer.

And we have had some great times with all of these activities and I have enjoyed the times traveling with our kids to games and the opportunity to help coach some of their teams. But sometimes things seem a bit over the top. I hate that seasons have gotten longer and now overlap. What is a kid supposed to do when two different coaches, from two different sports, want them two different places at the same time?

And I have witnessed ten year olds standing on the pitcher’s mound crying. Baseball is fun! I don’t think we ever cried while playing baseball unless we got stung by a bee we stepped on while rounding third base barefooted through a patch of clover or collided with a backyard swing set while attempting a Willie Mays over-the-shoulder catch.

And I know I have my own youth sports weirdness. I like making trading cards of my kids which is clearly mainly for my enjoyment, not the kids’ (if anyone needs a 2013 Rachel Sauder basketball card, I have extras). And we have had some great experiences with youth sports and it is not unusual for us to have conversations that start with “Remember that game when…” And I do think there are a lot of life lessons to be learned. How do you deal with being the best player on the team? How do you deal with not getting to play very much? What do you do when the coach puts you at a position you don’t like? How do you react to getting cut from a team? How do you react when the season is only half over and you don’t want to play anymore?

I recently finished reading Overplayed, which was co-written by Dave King who is the athletic director at Eastern Mennonite University where Zach, our oldest child, attends and plays soccer. It has some great practical insights for parents who may be figuring out how to proceed with youth sports (or not) in their family. It is written from a Christian perspective which may not resonate with everyone but I think everyone would find the insights from the perspective of a college athletic director helpful.