How do COVID-19 vaccines compare? Here’s what you need to know.

Time saver 4 min read

Last updated: Friday, October 8, 2021

It feels like decades have passed since the beginning of the global pandemic. Thankfully, today COVID-19 vaccines are widely available in the U.S. But many people still have a lot of questions about how the vaccines work and possible side effects.

We’re here to help you understand and compare COVID-19 vaccines and provide insight into the authorization process.

Comparing COVID-19 vaccines: mRNA vs. vector

There are a few different COVID-19 vaccines available right now. They all work to fight the coronavirus, but they do so a little differently depending on their design. Currently, there are two types of COVID-19 vaccines: mRNA and vector.

How do mRNA vaccines work?

You’ve likely heard a lot of buzz about this type of vaccine in the news because it’s a relatively new, highly effective type of vaccine. The mRNA COVID-19 vaccines contain a small piece of genetic code from the coronavirus. This code gives cells instructions on how to make copies of the spike proteins that are unique to the virus.

In response, our bodies know that these new spike proteins aren’t meant to be there, triggering an immune response. The result? If we are exposed to the coronavirus, our immune system already knows how to fight it off.

mRNA vaccines won’t alter your DNA in any way — they don’t have the ability to change your genetic code. You also can’t get COVID-19 from mRNA vaccines as the vaccines don’t contain the coronavirus, just a piece of its code. Both the Pfizer and Moderna vaccines are mRNA vaccines.

How do vector vaccines work?

Vector vaccines, also called carrier vaccines, act similarly to mRNA vaccines in that they instruct our bodies to make spike proteins that trigger an immune response. But the instructions given via vector vaccines are received through a slightly different process.

In vector vaccines, inactivate viruses act as a “trojan horse” — carrying the genetic code for spike proteins to cells. Our body identifies this code as something to fight against and trains our immune system to fight off the virus if we’re exposed.

You also can’t get COVID-19 from a vector vaccine — the inactivate viruses the vaccine uses aren’t the same as the coronavirus. The Janssen (Johnson & Johnson) vaccine is a vector vaccine.

If I had COVID-19, should I get vaccinated?

Yes. Even if you already had COVID-19, we don’t know how long immunity lasts after recovery and people have been infected multiple times. Therefore, it’s recommended that everyone get vaccinated to protect themselves and others.

If you recently had COVID-19 and have questions about getting vaccinated, consult with your doctor.

Are the COVID-19 vaccines safe?

Many companies worked diligently to create vaccines against the coronavirus that would quickly and effectively protect our communities.

Think of it like moving into a new house. If you’re moving on your own, it can take a long time. But if you call a couple of friends to help you out, you’ll all be able to complete the same job in a much shorter timeframe. That’s exactly what these companies did. They had big teams invested in creating the same product.

Even though the vaccines were produced quickly, they weren’t produced carelessly. The COVID-19 vaccines aren’t any less safe or effective than other vaccines that have taken longer to make. In fact, researchers were studying and working on mRNA vaccine technology for many years prior to the pandemic. That hard work set the foundation for quick vaccine development.

In addition, all vaccines go through rigorous clinical trials and Food and Drug Administration (FDA) approvals before being administered to the general public.

Comparing COVID-19 vaccines

Let’s take a look at the COVID-19 vaccines to learn more about when they were authorized, how they are administered and possible side effects.

The Pfizer-BioNTech vaccine

The Pfizer-BioNTech vaccine was the first vaccine to be approved by the FDA. The Pfizer-BioNTech vaccine requires strict storage in temperature-controlled units at approximately 94 degrees below zero Fahrenheit before it’s thawed for injection. Research is still ongoing to see if the vaccine can be stored at higher temperatures, which would make for easier distribution

  • Status: Received FDA approval on August 23, 2021.
  • Type of vaccine: mRNA
  • Authorized for: Anyone 12 years and older.
  • Dosage: Two shots, 21 days apart.
  • Common side effects: Chills, headache, pain, tiredness and redness or swelling at the injection site. Side effects are generally mild and usually subside within a few days.

The Moderna vaccine

Authorization of the Moderna vaccine followed quickly after the Pfizer vaccine. The Moderna vaccine’s effectiveness is similar to the Pfizer vaccine, but it can be transported and stored at typical freezer temperatures. It can be stored that way for up to 30 days, which makes for easier distribution. The Moderna vaccine has a slightly longer waiting period between doses than the Pfizer vaccine.

  • Status: Received FDA emergency use authorization on Dec. 18, 2020.
  • Type of vaccine: mRNA
  • Authorized for: Anyone 18 years and older.
  • Dosage: Two shots, 28 days apart.
  • Common side effects: Chills, headache, pain, tiredness and redness or swelling at the injection site. Side effects are generally mild and usually subside within a few days.

The Janssen (Johnson & Johnson) vaccine

The Janssen (Johnson & Johnson) vaccine is the first authorized carrier (vector) vaccine against COVID-19. The Pfizer and Moderna vaccines are very similar to each other, but the J&J vaccine is a little different in how it works. The most noticeable difference is that the J&J vaccine is administered as one dose—making it easier and faster to distribute.

  • Status: Received FDA emergency use authorization on Feb. 27, 2021.
  • Type of vaccine: Vector
  • Authorized for: Adults 18 years and older. Expected to start testing on children.
  • Dosage: One shot. (A regimen of two shots, two months apart, is being studied).
  • Common side effects: Fatigue, fever, headache, injection site pain or myalgia (pain in a muscle group or group of muscles). Side effects are generally mild and usually subside within a few days.
  • Very rare incidents of blood clots have been reported in people receiving the Janssen (Johnson & Johnson) vaccine, occurring at a rate of about 7 per 1 million vaccinated. The FDA and CDC are confident that the Janssen (Johnson & Johnson) vaccine is safe and effective in preventing COVID-19, however women under 50 years old should be aware of this rare but increased risk.

Which COVID-19 vaccine should I get?

Get vaccinated today. All vaccines are effective, and all vaccines are considered clinically equivalent in preventing hospitalization and death due to severe COVID-19.

Stay informed about your COVID vaccine options

At Virtuwell, we believe that everyone should have the factual information they need to make informed decisions about their health. For more information and the latest details on COVID-19 vaccines, visit the CDC’s website and check with your state’s health department.

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