Moderna vs. Pfizer: Is There a “Best” mRNA Vaccine?

Both of the mRNA vaccines available in the US are highly effective against severe COVID-19, but recent studies suggest that Moderna’s elicits a stronger immune response and might be better at preventing breakthrough infections.

Written byAlejandra Manjarrez, PhD
| 10 min read
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#TeamPfizer and #TeamModerna are two of the captions often found next to selfies of proud newly vaccinated people on social media. And both groups do have a reason to celebrate as the two mRNA vaccines available in the US have proved to be highly effective against severe COVID-19.

#TeamModerna when #TeamPfizer walks in. pic.twitter.com/5UimFI4rBf

Research published in recent weeks, however, suggests the Moderna vaccine’s advantage in terms of long-term protection. In multiple independent studies, significantly lower antibody levels and more vaccine breakthrough infections have been detected in the Pfizer/BioNTech-vaccinated population. These could be explained by a myriad of slight differences between the vaccines themselves: their distinct dosages, the intervals between the two doses, or the composition of the lipid nanoparticles used in each one. For now, all possibilities remain open.

By comparing vaccines and exploring the basis of their differences, “we are going to learn a ...

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Meet the Author

  • alejandra manjarrez

    Alejandra Manjarrez is a freelance science journalist who contributes to The Scientist. She has a PhD in systems biology from ETH Zurich and a master’s in molecular biology from Utrecht University. After years studying bacteria in a lab, she now spends most of her days reading, writing, and hunting science stories, either while traveling or visiting random libraries around the world. Her work has also appeared in Hakai, The Atlantic, and Lab Times.

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