SARS-CoV-2 is responsible for the COVID-19 pandemic that started late in 2019 and quickly spread worldwide. All viruses mutate over time, and this Coronavirus is no exception. Many viral mutations are not a problem, but some make the virus more powerful. That’s the situation with the new Delta Variant of SARS-CoV-2 that was first identified in December 2020 in India. It has now spread worldwide and is the dominant strain causing COVID-19 in the United States (80% of cases).
The Delta variant has changed the COVID-19 landscape and we’re now seeing a resurgence of the pandemic.
What we know so far….
- Delta is more contagious than the other SARS-CoV-2 variants (original one, alpha, beta, etc.). Recent reports indicate its as infectious, or more infectious, than Chicken Pox. One big reason it is more infectious is that there are 1000 times more virus particles in the nose of a person infected with Delta compared to the original strain. F. Perry Wilson of Yale University says,
“In a completely unmitigated environment—where no one is vaccinated or wearing masks—it’s estimated that the average person infected with the original coronavirus strain will infect 2.5 other people. In the same environment, Delta would spread from one person to maybe 3.5 or 4 other people. Because of the math, it grows exponentially and more quickly.”
- Vaccination is the best protection against Delta.
For the original COVID-19 strain, the Pfizer and Moderna vaccines prevent 94% of infections with COVID and are nearly 100% effective at protecting against serious disease (hospitalization, death). Latest studies indicate these vaccines are about 85-88% effective at preventing infection with Delta, and remain 95-96% effective at preventing serious disease with Delta.
- There is still more to learn about Delta.
Because it’s new, there are many unanswered questions about Delta:
- Does it cause more severe disease? Preliminary data suggest it might
- Are the symptoms different? Cough and loss of smell seem to be less common with Delta. And more typical “cold symptoms” with runny nose and sore throat seem more common.
- Is it associated with more “Long COVID syndrome”? Too early to know
- Is the incubation/transmission timeframe the same as the original strain? Don’t know.
For more information on this topic, check out this great article from Yale Medicine