What happens if you don’t get the second shot in a COVID vaccine two-jab regimen?

Credit: Getty Images
Credit: Getty Images

Two separate vaccines due to be released from pharmaceutical firm Pfizer and biotech Moderna appear to be more than 90% effective in preventing COVID-19. Critically, however, that’s only after people receive two doses taken 21 days apart for Pfizer’s vaccine and 28 days apart for Moderna’s remedy.

[S]tudies show just over 80% of people who get a two-dose vaccine for shingles, a viral infection that can cause a severe rash, typically return for the second treatment. Factor in the side effects associated with the COVID-19 vaccines, which include headaches, fever and muscle pain, as well as misinformation that is likely to circle around the vaccination, and the percentage of people who don’t return for a second dose for the coronavirus shot could be high.

The consequences of people skipping a second vaccine dose could be significant. Although the coronavirus is unlikely to become vaccine-resistant, that could change if millions of individuals only get one dose of a vaccine that requires two treatments, said biologist David Kennedy, who studies viruses at Penn State University and co-authored a recent paper urging drug makers to look for signs of mutation in the coronavirus.

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“In imperfect vaccines, that’s where we see resistance pop-up,” Kennedy said. “The more individuals who have one dose of these vaccines, the more concerned I would be.”

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