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Published on July 16, 2021

5 Facts to Know About SARS-CoV-2 (COVID-19) Variants From Cynthia Snider, MD, MPH

5 Facts to Know About SARS-CoV-2 (COVID-19) Variants

The Delta variant of SARS-CoV-2, the virus that causes COVID-19, now makes up more than 50% of all COVID-19 cases in the U.S. and is already the dominant strain in some states. Regionally, it is estimated to be 35% of cases with a doubling time of two weeks. This means that the Delta variant will be the major strain by mid to late August.

This is alarming because data suggest that the Delta variant is 40-80% more transmissible than the Alpha variant first identified in the U.K., which was 50% more transmissible than the original strain first identified in China – which means one case of Delta-variant COVID-19 can cause five to eight additional people getting infected if they are not vaccinated. We are already seeing increasing COVID-19 cases this week by at least 50-75% locally and statewide, respectively.

Here are five facts you need to know about SARS-CoV-2 variants:

  1. Unvaccinated or partially vaccinated individuals are most at risk for severe disease and hospitalization.
  2. Our current vaccines are safe and effective against the Delta variant and still prevent hospitalization and severe disease… for now.
  3. The vaccine uptake in the communities we serve is 46%, which is far below the 90% of all eligible people who need to be vaccinated to achieve herd immunity.
  4. The SARS-CoV-2 virus will continue to mutate more rapidly unless we reduce its opportunities through vaccination.
  5. The new variants have the potential to replicate faster and be better at defeating our current treatments and reducing the effectiveness of the vaccines. 

Cone Health remains committed to sharing the most recent COVID-19 information with you. We gather our data and facts from a variety of reputable sources, including Centers for Disease Control and Prevention, the U.S. Food and Drug Administration, Johns Hopkins University & Medicine, and The Commonwealth Fund. Here’s what we know:

  • As of July 15, nearly 34 million cases of COVID-19 have been reported in the U.S. and more than 608,000 deaths have been attributed to the deadly virus.
  • Between Dec. 14, 2020, and July 12, 2021, more than 334 million doses of the vaccine have been given in the U.S.
  • The FDA requires health care providers to report deaths of patients who have received the vaccine. No causal link has been found between the reported deaths and the COVID-19 vaccine.
  • Thanks to the vaccine, the number of COVID-19 cases has fallen from more than 300,000 per day in January 2021 (the height of the pandemic) to fewer than 20,000 per day in mid-June. 

We need your help to protect our community. If you have not been vaccinated yet, please consider doing so – if not for yourself, then for those around you who can’t. The vaccines we have available are proven to be safe and effective. And they are free. Please encourage your family and friends to get vaccinated now before the Delta variant is the predominant strain. Reaching the 80% threshold is the only way we will stop the SARS-CoV-2 virus from mutating into potentially more deadly and transmissible strains.

It’s time to roll up our sleeves. Learn how to get your shot at

About the Author

Cynthia Snider, MD, MPH

Cynthia Snider, MD, MPH, is the medical director of infection prevention at Cone Health.