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High school biology refresher. Let's bring it back old school.

As you are all likely aware of by now, COVID-19 cases are back on the rise which is contributing to what is now being called the "third wave". As of the July 30 reporting of data, Florida had a New Case Positivity rate of 18.9% (for comparison, the New Case Positivity rate ending 6/11/2021 was 3.4%). The New Case Positivity rate is the number of people who test positive for the first time divided by all the people tested that week, excluding people who have previously tested positive. This FLORIDA data can be found here. Locally in Duval County, by the August 9 reporting, the New Case Positivity rate was higher at 27%. 95% of the ICU beds in Duval County are occupied. Only 42.7% of COVID-vaccine eligible people in Duval County are fully

vaccinated. Duval county data can be found here.

Let's talk vaccines. I understand that this subject is deeply personal to many of you and that this is and has always been a sensitive topic. I'm not going to talk about the socio-ethical implications of vaccinations. What I want to discuss is purely the science of vaccinations. This is my job and responsibility as a physician. I present the science and evidence that allows a patient to make a responsible, well-informed decision. Our days are filled with products and results of research and evidence. Airplanes, electric cars, contact lenses, toothpaste, refrigeration. We build cities, countries and lives around evidence-based decisions on a daily basis. We don't think twice about questioning the evidence because we trust the scientists who have put in the work. On the other hand, we make other decisions everyday that are not based on science or evidence and still we don't think twice about questioning it, not once. Taking OTC multivitamins or supplements (or taking anything OTC that is branded "natural" for that matter), using artificial sweeteners instead of sugar, eliminating every source of carbohydrate from your diet, wearing copper jewelry, e-cigs are better than regular cigarettes. Those choices don't seem to have the same requirements to "prove" themselves safe and effective like others. Why? My job is to present the evidence so patients can make informed decisions. INFORMED decisions. Let's be clear. "INFORMED" in this context means -- evidence, data, objective measures. It does NOT include opinions, gut feelings, anecdotes, hearsay. Those are two different conversations. The type of INFORMED decision physicians talk about are based on data. Not on anecdotes.

What I hope to do is to make things a little more simple to understand. If you don't understand what everyone is talking about, then you really can't make an informed decision can you? Read that again. If you don't REALLY UNDERSTAND what everyone is talking about ... please do not offer pseudo-advice. Not when the stakes are this high. Please. If you want to be a part of the conversation, please at least understand the basics. This is information we all learned in high school biology. I promise we did. For this post, let's just first review the basics for viruses and herd immunity. In my next two posts, we will go into the immune system and vaccinations a little bit more.


Viruses and, specifically, RNA VIRUSES.

Unless you are a science savant, most of us don't really remember the difference between a virus and a bacteria and how a virus even works. A bacteria is a living thing. It contains all of the components to maintain its own survival without a host. A virus is not a living thing. A virus can't live on it's own. A virus is simply some genetic material. It needs a host cell in order to survive and replicate. In order to attach to a host cell, the genetic material needs to be protected by an outer covering, sometimes called an envelope. This is how a virus travels safely, within this protective envelope. The envelope finds a susceptible host cell, attaches to it and BAM! it makes contact and starts doing it's virus thing.

Here's how a virus works.

  1. The virus' envelope is able to attach to a host cell.

  2. Once attached, it can inject the viral genetic material into the host cell.

  3. The viral genetic material can then use the host cell nucleus to make copies of itself. The copies of this genetic material can then be used as instructions to tell that same host cell to make the exact proteins as in the original blueprint. Once the proteins are made inside the host cell, they can then be reassembled and make new virus particles. (Think of this host cell working like a 3D printer. The genetic material is the computer code that gives the 3D printer instructions on what to make).

  4. The host cell bursts and releases the new viral particles. The host cell dies.

  5. The new viral particles can then make their way within this new host OR outside of the host to another host to find other host cells to do the same thing. And now we're off to the races. Now we're cooking, says the virus.

Most of us have forgotten the differences between RNA viruses and DNA viruses. It's really not that important except to say that not all viruses are the same. RNA viruses are a very unique group of viruses. Some RNA viruses you may be familiar with are Ebola virus, Measles virus, RSV, Polio virus, and of course Coronavirus. RNA viruses are NOTORIOUS for their ability to mutate at very high rates. It's their thing. Their ability to rapidly change their genome and then emerge as a slightly different version is what RNA viruses do. Sometimes this helps the virus. Sometimes it doesn't. In the cases where it does help the virus, the virus can mutate and evolve and change enough to circumvent disease resistance in the population and overcome vaccine immunity. RNA viruses are smart, sneaky little boogers. If you think you might sit back and outsmart an RNA virus, well....



We've heard the term. Do you really understand what that means and why it's so important? Especially using COVID-19 as our living, breathing example. Look at the graphic below. The red color is the virus activity. When 0% of the population is vaccinated, the red color takes up the entire square. Makes sense right? As you see more of the

square become vaccinated, there is less of the red color that you see in the square. The virus affects fewer people in the square. When you see 95% of the square vaccinated, you see very little of the red color. That's an eradicated virus in that scenario. This doesn't work though if either not enough of the square gets vaccinated or if we take too long to get to 95% vaccinated because remember, this virus is trying to figure out how to mutate. Once it mutates, it could mutate enough to make the vaccine ineffective, and now we are back to square one (literally).

That's all I have for high school biology refresher, part 1. Hopefully, we'll start to see how this all comes together in part 2 when we start talking about the immune system and part 3 when we talk about vaccinations and *gasp* the dreaded mRNA vaccine.

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