March 16, 2021

How do the COVID-19 mRNA vaccines work?

Dr. Nicola Klein, director of the Kaiser Permanente Vaccine Study Center, provides insight into this new vaccine technology.

Serena Neeley, RN, gets vaccinated with one of the mRNA vaccines at the Kaiser Permanente Southwood Comprehensive Medical Center in Jonesboro, Georgia.

New virus. New vaccine technology.

The very first vaccines authorized to help prevent COVID-19 use mRNA, or messenger RNA, technology. While the technology itself is not new, using it in a vaccine is.

To better understand what an mRNA vaccine is and how it can help protect us, we spoke with Nicola Klein, MD, PhD, director of the Kaiser Permanente Vaccine Study Center.

“It’s an exciting technology,” said Dr. Klein. “There is good evidence from the vaccine clinical trials showing that the mRNA vaccines are highly effective and appear to be safe.”

You can help end the pandemic by getting a COVID-19 vaccine when one is made available to you and by understanding how the vaccines work and sharing that information with others.

How does an mRNA vaccine work?

When you look at images of the coronavirus, you see spikes sticking out from all sides; these spikes are actually proteins. The mRNA vaccines for COVID-19 contain the instructions cells need to make a piece of the spike protein but not the fully functioning COVID-19 virus.

The formation of these spike proteins tricks your body into making an immune response against the spike protein, which works to protect you against the COVID-19 virus if you are exposed to it. This immune response is what gives you protection against the disease.

How are mRNA vaccines different from traditional vaccines?

Most traditional vaccines inject an inactivated or weakened (attenuated) virus into the body to trigger an immune response. For example, the annual flu vaccine uses an inactivated virus. The vaccines for measles and chickenpox use a live attenuated virus.

The mRNA vaccines teach our own cells to make a piece of the spike protein that is unique to the coronavirus, and that causes the body to have an immune response.

With any vaccine, though, the goal is the same: to trigger an immune response that helps protect us from getting infected if the real virus enters the body.

The first 2 authorized COVID-19 vaccines in the United States use mRNA technology. Is there a reason for that?

Scientists began developing all the potential COVID-19 vaccines at roughly the same time using different types of vaccine technology. A big part of why the mRNA vaccines were authorized first is because making a vaccine using mRNA technology is a relatively fast process.

Making mRNA is a standard technique in a lab. So, once researchers got the genetic sequence of the coronavirus — essentially the instruction manual for making it — they were able to make the vaccine quickly.

What would you say to people who are afraid that mRNA vaccines alter your DNA?

It’s simply not true. In fact, it’s the other way around. DNA makes RNA. The mRNA in the COVID-19 vaccines only goes into a certain part of the cell — the outer part known as the cytoplasm. It doesn’t go into the cell’s nucleus, the part of the cell where the DNA lives. And, mRNA doesn’t last very long because its job is to give the information to the cell — a blueprint for how to make a protein — and then it goes away.

The mRNA vaccines currently authorized for use in the United States are safe and effective. By getting vaccinated when it’s your turn and continuing to do the things that work to save lives — wearing a mask, washing your hands frequently, avoiding gatherings, and keeping your distance from others — you’re doing your part to help end the pandemic.

Find the latest information on vaccine eligibility and how to get a vaccine when you’re eligible at Members and nonmembers can also call the KP COVID Vaccine InfoLine at 1-855-550-0951, available 24/7.