Herd Immunity


The measles outbreak in Washington keeps getting more distressing. Currently, there is a small selection of doctors willing to give exemptions to parents just because. I believe these doctors should be punished, because they are risking a lot of lives. There are currently 325 million people in the US. 3% of them are not immune to measles despite vaccinations. Meaning there are more than 9 million Americans that don’t get measles simply because herd immunity prevents measles.

Since 9 million is a lot of people to wrap your mind around, we’ll think about it in smaller terms. Between Facebook, Twitter, my blog, and my newsletter, I have roughly 2,000 followers. That means 60 people who follow me are not immune to measles despite being vaccinated.

And as I’ve said before, measles is one of those lovely diseases that becomes contagious before symptoms begin to show. This means a child with measles can infect people around them as early as 7 days before they start having symptoms. 7 days is a long time to spread measles without knowing you have it.

This becomes an even scarier thought when you consider how many people a child can come into contact with before showing symptoms: school, daycare, grocery stores, after-school activities, and family outings to the park.

This early exposure is why we have outbreaks of diseases like influenza every year. Once a person is sick, everyone avoids them. Until then though, they are exposing a lot of people to their germs. Influenza and viral pneumonia are usually only contagious for a day or two before symptoms show and neither is a very hearty virus, they don’t do well when exposed to the elements. Unlike measles, when exposed to the environment, influenza usually only survives a few hours. Measles can survive for a day or more on surfaces even in cold weather and rain.

However, because 89% of people in the US are vaccinated against measles, even when exposed to it, they don’t get it. Unfortunately, that percentage has been dropping since 2002. In 2002, the CDC listed measles as eradicated. Enough of the US population had been vaccinated against it that outbreaks and epidemics were unlikely. Cases still popped up, especially among unvaccinated populations, but we weren’t in fear of major spread.

But as I said, that percentage has slowly been dropping. As of 2018, we’d dropped to only 86% of the US population being vaccinated against measles. It doesn’t sound like a lot, but it means 9 million children have not been fully vaccinated against measles in just 16 years. And three percent is enough to significantly weaken herd immunity.

Now, the measles outbreak in Washington might be spreading. It made the news when it was 33 cases of measles. Now the state of Washington has more than 100 cases. Oregon has 22 cases and Idaho has 15 cases. These lower numbers in Idaho and Oregon aren’t alarming by themselves, but between 2016-2018 Oregon only had a total of 31 cases of measles. Idaho had 12. And the same time period in Washington had 37 cases. In two months, Washington has seen triple the number of cases in 2019 as they saw in the three previous years combined.Not surprisingly, Washington has one of the lowest vaccination rates in the country. It also has a larger population than the state of Oregon and Idaho combined.

For people like me, without measles immunity, Washington might as well be a third world country. Worse, most people who don’t have immunity don’t know it. Unless you work somewhere that requires you to have a titer test for measles (some health care facilities require them) or you get measles, you may not realize you’re part of the more than 9 million people that is not immune to measles.

I know, only because I got measles and this resulted in the University of Missouri demanding new MMR vaccinations followed by a titer test when I was accepted to attend college there. The only reason I haven’t battled measles multiple times is because of herd immunity. To people like me, herd immunity is literally a life saver. The mortality rate for measles is higher in adults than children. But if you don’t know you aren’t immune, and you are exposed to measles as a result of say a vacation, then you are taking measles back to your home, where 3% of the population is not immune.

Besides, it should be terrifying anytime the prevalence of a disease triples. This is how the H1N1 pandemic started in 2009. A pandemic is a global outbreak of a disease. It isn’t just Americans that suffer from 3% of the population not having immunity. Nearly all Western countries require vaccinations. That 3% applies to the population of the UK, Germany, France, Italy, so on and so on. In countries without vaccination protocols and/or where the population doesn’t have easily accessible vaccinations like Mexico, India, China, Egypt, and tons of other countries, the chances of outbreaks for measles is much higher and worse.

Measles has an 8% serious complication risk for children. This means 8 out of every 100 children that catches measles will suffer brain damage, hearing loss, digestive issues, lung issues, and death. In adults, it’s about 20% that suffer severe side effects from measles.

Going back to my original example, this means of the 60 people that follow me that don’t have measles immunity, 12 of them will either have hearing loss, brain damage, lung damage, problems with their digestive tract, or will die as a result of catching measles. On a national scale, if measles becomes an epidemic, more than 2 million people could suffer these symptoms or die as a result of the loss of herd immunity. This is especially difficult for someone like me, I have a chronic disease that affects my immunity to every day bugs, because the nerves in my digestive tract are hyperactive due to CRPS, I don’t have a good immune system. A poor immune system battling a disease it already can’t handle, makes me very high risk for death and the other serious side effects as a result of measles.

Herd immunity is defined as 89-95% of the population being vaccinated against a disease. It is that number the prevents outbreaks, epidemics, and pandemics. That 89-95% has immunity to the disease. If they catch something like measles, their bodies recognize the disease and immediately begins pumping out antibodies to kill the virus and dead viruses aren’t capable of causing illness.

Then there is something called partial immunity. Some portion of our population regardless of vaccination status is immune to measles. Most of them had a very mild case of measles previously and so when they are exposed to the virus again, their body begins to make antibodies to kill it. They usually get sick, but only have a mild case and they aren’t as contagious as those that do not have immunity.

However, it is the 89-95% that keeps the rest of the population from getting sick. Partial immunity means you probably won’t spread it to every Tom, Dick, and Harry that crosses your path, but that complete immunity population that received their immunity via vaccines are incapable of spreading the disease at all. Even if they got an extreme form of measles and got sick from them, their antibodies are killing the virus fast enough to keep them from being contagious. They are the ones that keep the 3% of us without immunity from getting sick, along with the 8% or so of Americans that are unvaccinated against measles. While 3% of children born after 2002 are not vaccinated against measles, roughly 11% of the population was not vaccinated nor had immunity to measles even with vaccinations in 2002. Only in 2014, did this 11% result in more than a hundred or so cases of measles in the US. In 2014, there were 616 cases of measles in the US, the highest number of cases in a single year since the 1980s.

But as I said, our vaccination rate has dropped from 89% in 2002 to 86% in 2018. We no longer have herd immunity to measles. Without it, every outbreak runs the risk of becoming an epidemic. This is especially disturbing given a new study coming out the UK. Between 2015 and 2018, whooping cough cases increased by 7%. The US saw a similar rise at 6%. Most of us have been vaccinated against whooping cough (pertussis). However, like measles, there will always be a small portion of the population that despite vaccinations, is not immune. As immunization rates have fallen in the US and UK, pertussis cases have risen and like measles, if you have been vaccinated, there is no reason for you to suspect you aren’t immune, until you get it.

Interestingly, most anti-vaxxers don’t realize they are benefitting from herd immunity. If you don’t vaccinate your child against measles, there’s a good chance your kid will still probably never get it, because we have herd immunity. It isn’t until your child tries to travel overseas that they’ll find their lack of immunizations a serious problem. Even with my titer results, I was forced to get a completely new set of MMRs in 2006 when I decided to travel to Germany. And I was told by my doctor that he would not sign off on the special immunization form I needed if I didn’t get them. I got them. I didn’t get measles, but again, Germany enjoys herd immunity from measles. When I jokingly told my doctor I was going to move to Belize, I was told it would be inadvisable, because I’d probably get measles and at 39, my risk of serious complications was high.

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