I have gotten a lot of questions about the COVID-19 vaccine lately, so this seems like a good time to give my take on the topic.

Let me start by saying that it probably isn’t a surprise to hear that I am pro-vaccine. That isn’t to say that I “believe” in vaccines with some sort of religious fervor. This is science, not some pseudo religion. Even though pro-vaccine people like me say they “believe” in vaccines, that is really a shortcut to say that we are convinced by the scientific evidence on vaccines collected across hundreds of years and from billions of people about their safety and efficacy. We mean that we are convinced by the scientific evidence that vaccines are effective in preventing you from getting sick. We are convinced that vaccines are safe and that harmful effects are rare. We are convinced by the scientific evidence that, when these harms occur, the benefits of vaccination still outweigh the harms. Belief has nothing to do with it. Science doesn’t care if you believe or not.

The reason I am so excited about this vaccine is not just because it will stop this pandemic – this is way bigger than that. This vaccine is the proof that mRNA-based vaccines work. This is the demonstration for the new way we will develop vaccines. 

Moderna designed its vaccine in two days. Two days. Let that sink in. They didn’t have to grow the virus in a lab. They didn’t have to worry about all the other proteins that can cause reactions. They took a published genetic sequence and created a vaccine in about the time it takes to get an Amazon order. The first batch was ready for use in less than a month, and that was the first time we used this approach. It will only get faster.

The vaccine works

Both RNA vaccines have shown an efficacy around 95% after two doses; the Pfizer vaccine had an efficacy of 52% after just one dose. 

The math on this is very simple. There were eight cases in the 21,720 people who got the vaccine in the Pfizer trial. There were 162 in the 21,728 who got the placebo. If we calculate the incidence of disease in both groups, and divide one by the other, we get: (8/21720) / (162/21728) = 0.049401. 

In other words, vaccinated people have about 1/20th the incidence of disease as the unvaccinated. The easier way to say this is 1-0.049401 = 95%, which means that the vaccine prevents 95% of the infections. There were also no hospitalizations or COVID deaths in the vaccinated group. 

We do have to remember that there is a difference between efficacy (how it performs in the trial) and effectiveness (how it performs in the real world). In the trial, people got two doses at the ideal interval. In the real world, some will not get the second dose, and some will get it at the wrong interval. But overall, it works really, really well.

The vaccine is safe

I have seen a lot of comments from people who think the vaccine trials were rushed and they aren’t safe, and that they are going to be “guinea pigs”. 

This vaccine has gone through the same clinical trial that every drug and vaccine on the market has gone through. It was a randomized, double blinded, placebo-controlled trial of about 40,000 people. That means 20,000 were vaccinated and 20,000 got the placebo (a saline injection). The people get randomly assigned to either the vaccine or control groups, and neither they nor the researchers know what they received. With a group that large and a disease spreading as rapidly as COVID, the trial can be completed rather quickly. 

With two groups of 20,000 participants, it was easy to identify the most common adverse reactions. Injection site pain, fatigue, headache, muscle and joint pain, and chills were the most common, and they more often occurred after the second dose. This isn’t a bad thing, as those side effects are evidence of an immune response. 

More severe adverse events were rare, and there was no evidence of a causal relationship with the vaccine. People died in the trial (in both the placebo and control group) at the rate expected from the general population. 

It doesn’t cause Bell’s Palsy, and allergies aren’t a contraindication

Concerns about Bell’s Palsy (a weakness of the muscles on one side of the face) seem to be a favorite excuse for people not wanting the vaccine. For most people, it is mild and self-limited. In the U.S., about 35 people per 100,000 develop it per year. That means in 20,000 people followed for four months (like this trial), three people are expected to develop it. In the Moderna trial, three people in the vaccine group and one in the placebo group developed it. 

When people read about the vaccine causing three cases of Bell’s Palsy, they are missing the context. The way it should be explained is that the vaccine didn’t cause any cases of Bell’s Palsy above what is expected. 

There were also no anaphylactic or severe hypersensitivity (allergic) reactions in either group during the trial. However, two U.K. health care workers developed a reaction after vaccination and the U.K. advised people with “a significant history of allergic reactions” to avoid the vaccine until we had more information. These aren’t people who get puffy faces if they eat a particular food or get congested when the mulberry trees are blooming. These were people who had such serious allergy problems with general anaphylaxis that they carried an Epi Pen with them at all times. The CDC does not list it as a contraindication but does recommend that you weigh that risk against the benefit. 

It’s not made using aborted fetal tissues

It’s pretty much impossible to avoid these cell lines altogether in research, so if you look hard enough, you will find some link between every pharmaceutical or vaccine on the market and these cell lines (at the very least, much of the research that forms the basis of modern cell biology and virology does). 

While some COVID vaccines are produced in cell lines from aborted fetal tissue, the two FDA-approved vaccines, Moderna and Pfizer, do not use these cells lines as part of production. 

Several Catholic bishops in Colorado penned an open letter that stated “their use is morally acceptable since neither company used fetal cell lines from an aborted baby at any level of design, development, or production. However, we must also acknowledge that these two vaccine options are not untouched by abortion, as both relied on fetal cells from an aborted baby for one of the confirmatory lab tests. In our current circumstances, when better options are not available, the use of the Pfizer and Moderna vaccines remains a morally valid option.” 

Get it even if you’ve already been infected; and no, it won’t change your DNA

Not only can you be vaccinated if you’ve had the disease, the CDC recommends it. 

And with respect to DNA, yes, the idea of injecting genetic material into people seems to make a good prologue to a zombie apocalypse movie. But that is a complete misunderstanding of what is going on here. 

It’s been a few years since many of you have taken a biology course, so let me explain why that can’t happen. Your genes are encoded in DNA. For your body to use the genetic instructions, it has to read the DNA and create messenger RNA (mRNA). The mRNA serves as the instructions to produce a protein. In this case, your body is getting the instructions from outside without reading the DNA. The virus normally does this when it infects you, creating messenger RNA for your body to produce more virus. In this case, it just creates the protein that causes your immune system to respond and knock it out. 

The important thing to know is that there is no biological mechanism in your body to convert the mRNA back to DNA. If there were, humans would have been wiped out by viruses before they ever had a chance to evolve. Think of it like printing a recipe from the internet. Printing it doesn’t change the recipe on the internet, and you can’t shove another printed recipe into your printer and have it change the internet either.

The mutations found in the UK aren’t going to make the vaccine useless

SARS-CoV-2 has accumulated mutations at the rate of one to two per month. The strain that infected the U.S. isn’t exactly the same one that started in China. The one that was discovered in the U.K. has 23 mutations in it. Because of redundancy in the genetic code, six of these mutations have no effect (think of it like spelling color with the British spelling “colour” – the sentence means the same thing). There are three deletions and 14 non-synonymous (i.e. it changes the amino acid coded for). These all can lead to shape changes, and antibodies recognize invaders based on shape. 

We do know this when we develop vaccines, so we don’t just target one small region. The vaccine results in the production of polyclonal antibodies by your immune system, or different antibodies to all different areas of the protein so it can still recognize it with mutations. Think of it like this: you still recognize your friend after a nose job or a haircut because you look at a lot of different areas of their face, not just the one. The immune system does the same thing.

Nutrition isn’t a replacement for the vaccine

While I don’t disagree that proper nutrition will help your immune system in general, it is not a replacement for the vaccine. Your immune system running at peak performance is not going to prevent you from getting infected. An apple a day will not keep COVID away. Sure, it might help you recover or not be as sick, but it cannot stop infection. If it could, we wouldn’t be dealing with this outbreak. 

People think vitamin D is a cure – it isn’t. That’s a complete misunderstanding of the research on vitamin D and COVID. People with a vitamin D deficiency fared worse than those with normal vitamin D levels and bringing their levels back to normal made them fare the same as everyone without a deficiency to begin with. Vitamin D doesn’t cure COVID, nor do any other supplements. I don’t understand people who don’t trust an FDA-approved vaccine but will take a supplement completely unregulated by the FDA, but that’s a rant for another day.

The FDA has issued 152 warning letters to date against companies making fraudulent COVID claims on unregulated products. There isn’t a single supplement that has completed a clinical trial and shows any efficacy against COVID-19. I wish that were not the case, but all dietary supplements are going to do is give you expensive urine.

I’m getting mine as soon as I can, but not until my turn

Our vaccination priority groups are determined to give us the maximum benefit given limited supply. Pfizer's CEO, Albert Bourla, a person who could very easily get vaccinated before anyone else, has said he and the Pfizer executives were going to wait until it was their turn, as they are not frontline health care workers.

Personally, I am OK waiting a little while because there are other people at higher risk than I am. Yes, I work in public health, but I am working from home and I’m not dealing directly with the public. Sure, I am a professor, but my classes are online. Even if I am in those priority groups, I am at the back of them. That doesn’t mean I won’t go the first day they let me; it just means that I will wait my turn.

The short version of this post: get vaccinated as soon as you are eligible. I will. It’s safe. It’s effective. And it might save your life and the lives of the people you care about.