COVID-19 Vaccines — Starting 2021 on a Hopeful Note

Betty Chaffee/ January 6, 2021/ Coronavirus, COVID-19, immunization, vaccines/ 5 comments

Who would have thought that a needle in the arm could bring such a huge smile to so many faces? As a pharmacist immunizer, I was blessed to be one of the first healthcare workers at St Joseph Mercy hospital in Chelsea to be vaccinated in late December. My second dose is on the calendar for later this month. I'm happy to be able to immunize other folks, too, and spread the hope it brings. It finally feels like the world is on its way to overcoming the pandemic that has kept many of us isolated, unemployed, and/or frightened for almost a year now.

A big thank-you to all who sent in questions and comments about COVID-19 vaccination! There were too many good questions to get them all answered in one post, but let's get started answering some of them.

Some basics about COVID-19 vaccines

Two vaccines are currently in use in the United States, one made by Pfizer-BioNTech and one by Moderna. They've both been authorized for emergency use by the FDA. Emergency use authorization (EUA) is different from FDA approval (licensure). EUA can be granted by the FDA when a new product shows efficacy and safety in treating or preventing a disease during a public health emergency. EUA only allows use of the product during the health emergency -- after that it has to go through the traditional approval process in order to be used.




Both COVID-19 vaccines were created using messenger RNA (m-RNA) technology. In short, m-RNA teaches cells how to make all kinds of proteins like enzymes, hormones, and others. In this case, vaccine researchers learned the genetic code of the SARS-CoV-2 spike protein, and then produced m-RNA that teaches cells to make a protein just like that spike. Once that protein is produced, the immune system recognizes it as an antigen and starts making antibodies against it. Then when the real virus invades in the future, the immune system is ready to fight it off.

Traditional vaccines also use antigens that cause the body to produce antibodies. One example is the flu shot which contains inactivated virus particles. That technology works, but finding the right antigen and then mass-producing it takes a long time. m-RNA technology avoids that time-consuming step by using our own cells as tiny antigen manufacturing plants. That's a large part of the reason these vaccines are ready for use so quickly.

How did these vaccines come about so quickly?

Many people have voiced concern over the speed at which these vaccines came to market. There's worry that steps were skipped, studies weren't rigorous, or important information may have been ignored. But the reality is that many things came together perfectly to allow vaccine development quickly. 

We already talked about the way m-RNA vaccines save time identifying and manufacturing an antigen. But there are other reasons for the speed, too. First, governments all over he world subsidized the development, manufacture, and research. Having resources to do the work makes a huge difference in how quickly it can be done. Next, FDA allowed some of the usual steps in vaccine development to be done simultaneously instead of sequentially. That also saved quite a bit of time. But the other thing is that the mRNA technology was ready. All scientists needed was the genetic code of the SARS-CoV-2 protein spike, which was provided early on in the pandemic, and they were ready to start making and studying a new vaccine.

Does m-RNA technology have any effect on our own DNA?

No. m-RNA doesn't get into the center of cells where genetic material is stored and manufactured. After injection, it simply gets into surrounding cells and begins the process of protein production. Our body then quickly recognizes the m-RNA as foreign and breaks it down - it doesn't last long once it's done its job.

How can we know about other potential safety concerns with m-RNA technology?

m-RNA technology has been studied for many years; during that time initial problems were solved and the technology refined. (Here's an interesting report on the history of m-RNA technology if you're interested.) But no medicines based on that technology have been authorized for use until now. So while initial vaccine studies haven't shown major problems, the fact is that ongoing data collection and surveillance is the only way we'll learn about unexpected or rare side effects. In my next article you'll learn how you can help to provide information about vaccine safety!

Are there substances in the vaccine or vial stopper that may be dangerous?

People are frequently concerned about preservatives in vaccines, especially thimerosal (mercury). Most vaccines are now manufactured without heavy metals, though it's always best to check if you're concerned. In the case of these two new vaccines for COVID-19, neither contains preservative.

Another good question was about latex in the vial stopper. Historically, vial stoppers for injectable medications were made from rubber. But in recent years it's become evident that latex allergy may develop with repeated exposure. Most injectable stoppers aren't made with latex these days, but it's always best to check. In the case of these vaccines, neither vial stopper contains latex.

Will COVID-19 vaccines last a lifetime or require regular boosters?

Unknown. Most infectious diseases require an initial series of vaccinations (think shingles, measles, hepatitis), but none after that. Rarely only one is needed (adult pneumonia), while we need regular boosters for diseases like influenza and tetanus. Researchers will need to follow people who've been vaccinated for COVID-19 to learn how long the immunity lasts.

At the same time, we know that SARS-CoV-2 mutates -- that's not a surprise, all viruses do that. We don't know yet whether mutations will decrease vaccine protection. Recent mutations you may have heard about aren't expected to affect vaccine protection, but ongoing research will be needed.

How effective are COVID-19 vaccines?

The results of initial safety and efficacy studies were similar for the two vaccines. About 70,000 people participated in studies between the two vaccines. Roughly half received the active vaccine while the others received a placebo injection. There were about 370 cases of COVID-19 among the participants, but fewer than 20 occurred in those who received the vaccine. That's means both vaccines are about 95% effective at preventing COVID-19.

What happens if a person who's vaccinated actually gets sick with COVID? Will it be as severe?

Both studies looked at the occurrence of severe disease from COVID-19. Of the 40 cases of severe disease reported in study participants, only one occurred in those who had received active vaccine. That points to the possibility that the vaccine kept those who contracted COVID-19 from developing severe disease.

Are the Moderna and Pfizer-BioNTech vaccines identical?

No. Though there are many similarities, there are some differences, too. It's not clear yet whether the differences will be important over time, but at least for now they are NOT considered interchangeable. Here are some differences:

  • Pfizer-BioNTech can be used for those aged 16 and up, Moderna is for those aged 18 and up.

  • Pfizer-BioNTech's second dose is given at 3 weeks, Moderna's at 4 weeks.

  • Pfizer-BioNTech uses a smaller volume per dose (0.3ml); Moderna uses 0.5ml per dose.

When you get your first dose of vaccine, be sure to get a card showing which vaccine you were given. Your second dose should be the same type of vaccine, given at the appropriate time.

Risk and benefits

Just like all medicines, COVID-19 vaccines have risks and benefits to consider. And just like all health concerns, COVID-19 also carries risks. Knowing the facts is the first step toward making a decision on vaccination that's right for you. I hope this article has given you some helpful information. Readers had questions about side effects of COVID-19 vaccines, too. That will be a topic for the next article, along with information about how you can participate in safety monitoring.

There are still quite a few unknowns about COVID-19 vaccines, and new questions being raised all the time. Please send your vaccine questions my way and I'll continue to do my best to answer them! Contact us at BetterMyMeds for any help you need with medications or vaccines -- our goal is to help you stay as healthy as possible.



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About Betty Chaffee

Betty Chaffee, PharmD, is owner and sole proprietor of BetterMyMeds, a Medication Management service devoted to helping people get the maximum benefit from their medications.


  1. Thanks for clearing up some confusion. I had been under the impression that the Moderna formula only required a single dose. Apparently, that was wrong information. It’s good to know that its important to know which shot we need for the 2nd dose. Thanks for the link for the mRNA history. Will read that now

    1. Hi Tony,

      It’ll get even more complicated as more vaccines become available. There are several different types being studied – I think only one of them is a single dose vaccine but we’ll learn more as time goes on. Let me know what you think about the mRNA history article. I found it fascinating and a good read!

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