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Research and Innovation

Vaccine Q&A: Which Vaccine Should I Get? Does It Matter?

covid vaccine clinic parking sign
Photo credit: Joshua Hoehne.

Which vaccine works best? Should I get one shot or two? Is there any real difference in terms of protection? If you are wondering about these things, we have good news for you.

To address those questions, we spoke with Matt Koci, a virologist and immunologist whose work focuses on host-microbe interactions in birds. Koci is a professor in NC State’s Prestage Department of Poultry Science.

This post is part of a series of Q&As in which NC State experts address questions about the vaccines on issues ranging from safety to manufacturing to how the vaccines will be distributed.

The Abstract: With three vaccines authorized for use in the U.S., and more people about to be approved for vaccination, many people want to know if one of the vaccines is better than the others. Is there a difference? How do people pick which one is right for them?

Matt Koci: Great questions. The short answer is that the best vaccine is the one you can get first. I know that sounds like the answer your parents gave you when you asked who their favorite child was, but all three vaccines are pretty similar in the protection they provide.

Here are five questions that people can use to assess the vaccines. (This is how I decided that it didn’t matter to me which vaccine I got.)

1) Which one is better at protecting me from death?

All three vaccines being used in the U.S. (as of April 2021) are 100% effective at preventing death from COVID-19.

2) Which one is better at keeping me out of the hospital?

Again, all the vaccines currently being used are 100% effective at keeping you out of the hospital from COVID-19. [Note: in the Moderna trial one person in the vaccine group was hospitalized, but they weren’t confirmed to have COVID-19 positive.]

3) Which one is better at preventing mild to moderate symptoms?

Again, believe it or not, they are all about the same here. When the Johnson & Johnson vaccine was first announced, the media made a lot of noise about how the two mRNA vaccines had 94-95% effectiveness and J&J was 72% effective at preventing mild to moderate disease. But as we’ve continued to follow people who’ve gotten the J&J vaccine we’re learning that the level of protection goes up with time, and maybe we weren’t comparing apples to apples.

TA: Time out — can you explain that last part for me a little more?

Koci: For all the vaccine trials, the companies focused on assessing effectiveness starting two weeks after the last shot. The J&J is just one shot, so the clock starts two weeks after that shot. However, the clock doesn’t start for the mRNA vaccines (Moderna and Pfizer) until two weeks after the second shot. That’s 5-6 weeks after you received your first mRNA shot. If you line up the comparisons based on the first shot instead of the last shot the J&J vaccine looks to be about as effective as the mRNA vaccines.

TA: Okay, sorry for interrupting. What are the other two questions you can use to assess the vaccines?

Koci: Number three was about mild to moderate symptoms, so….

4) Which ones protect better against new variants?

Right now, they all do about the same against the variants we know about. Other variants may pop up that change this equation, but that is no reason to wait. The sooner we get everyone vaccinated, the fewer variants we’ll have to deal with. And even if a new variant pops up, that doesn’t mean the current strains disappear. You still need protection from them.

I’ve had several people say “there’s no point in getting vaccinated if a new variant is just going to emerge down the road anyway.” That’s like saying some thieves will figure out how to pick the locks on my house, so there’s no reason to lock the door.

5) Which vaccine is safest?

All three vaccines are safe. There are some minor differences in which ones might cause more or less temporary (12- to 24-hour) flu-like symptoms, but those are minor.

Ultimately, from a “what protects me from the virus” standpoint, there really isn’t a difference between the vaccines. So, the choice comes down to which vaccine are you the most comfortable getting. The important thing to know is that all of the options will protect you, so pick the one you feel best about.

We’re so close to being able to get this virus under control and start to go back to our lives. We can’t do that without vaccines. So please get vaccinated when you get the opportunity.

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  1. Missing questions:
    Does age play a role in determining which vaccine is most appropriate?
    Do comorbidities play a role in the choice of the vaccine?
    Do combinations of age and comorbidities play any role in determining which vaccine is least likely to cause problems? For example, do different vaccines affect people over 70 with heart and lung problems more than younger, healthier people?