What's different about the delta variant, now COVID-19's dominant strain

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On Aug. 23, 2021, the U.S. Food and Drug Administration approved the Pfizer COVID-19 vaccine for the prevention of COVID-19 disease in people 16 and older. As what we know about COVID-19 evolves, so could the information contained in this story. Find our most recent COVID-19 blog posts here.

“Fastest and fittest” yet. That's the World Health Organization’s description of the delta COVID-19 variant, which is quickly spreading throughout the United States and the world.

First identified in India, delta is now the dominant strain in the United States, accounting for the majority of new COVID-19 cases. In Ohio, delta will most likely knock out the main strain here, known as alpha, which originated in the United Kingdom. The number of new COVID-19 cases caused by delta is doubling about every two weeks.

The U.S. Centers for Disease Control and Prevention says delta is a “virus of concern,” and for good reason. It’s transmitted faster and more efficiently than any other strain out there. It’s at least 50% more contagious.

What does all this mean for us? It’s simple — if you haven’t been vaccinated, you’re more at risk of getting and spreading COVID-19 because it’s so much more contagious. COVID-19 hotspots are expected to pop up in communities where vaccination rates are low. That translates into more hospitalizations and deaths.

In May, 99% of COVID-19 deaths in the United States were in unvaccinated people.

Because this is a new variant, it’s not known if it’s more deadly. Some data indicate it may cause more severe illness, but we don’t know for sure. The good news is that public health data from England show that mRNA vaccines like Pfizer and Moderna provide a high level of protection from delta. Johnson & Johnson recently released data showing its vaccine is also effective in combating delta. It’s important to remember that COVID-19 vaccines aren’t 100% effective. There will always be breakthrough cases, but the amount of protection COVID-19 vaccines provide is impressive.

With the increase in COVID-19 cases and loosening of restrictions, some are wondering what to do to protect themselves. Put a mask on, social distance from others, limit outings?

If you’re not vaccinated, the answer is obvious: Get the vaccine. Not only will it protect you but everyone you interact with.

If you’re already vaccinated, your antibodies are providing ample, but not foolproof protection. If you want to skip large gatherings or slip a mask on, go ahead. It’s not only your physical but mental well-being that’s at stake.

Ashley Lipps is an infectious diseases physician at The Ohio State University Wexner Medical Center and an assistant professor in the Division of Infectious Diseases at The Ohio State University College of Medicine.