July 14, 2021
In July, an outbreak of COVID-19 was documented in a single Massachusetts town; 469 people there tested positive, including 346 people (74 percent) who had been fully vaccinated. Genomic sequencing showed that 90 percent of 133 cases that were sequenced were caused by the highly contagious variant of SARS-CoV-2 – the virus that causes COVID-19 – known as the Delta variant.
The Delta variant, which is also known as B.1.617.2, has been making headlines since the winter as it spread its way across the world. It was first identified in India in December 2020, then discovered in the United States in March 2021. People in all 50 states have now tested positive for COVID-19 caused by the Delta variant. The Center for Disease Control and Prevention’s (CDC) national genomic surveillance program estimates that between 78 and 86 percent of new COVID-19 cases in the U.S. are caused by the Delta variant.
Some fully vaccinated people who become infected with the Delta variant don’t experience symptoms, while others do, including some of the people in Massachusetts who were a part of the outbreak. Whether or not vaccinated people experience symptoms, it’s possible that they may pass the Delta variant to others, including the non-vaccinated. For this reason, the CDC revised its recommendations for fully vaccinated people on July 27th: It now recommends that fully vaccinated people should wear masks when they’re in indoor public spaces with a substantial or high risk of transmission.
Doctors and researchers are still learning about the Delta variant, but they know many things so far.
Here are three things that everyone should know:
- The Delta variant is more contagious than other SARS-CoV-2 virus strains. Research has shown that the Delta variant spreads more easily between people, and it appears that people are transmitting the virus to others sooner than people spread the original strain of the novel coronavirus. New data from Massachusetts shows that fully vaccinated people can become infected and experience symptoms, although no deaths were reported among the vaccinated there.
Additionally, one recent study from China found that people who were presumably unvaccinated and infected with the Delta variant had a viral load within their respiratory systems that was 1,000 times higher than the amount of virus that was present among people who had been infected by the original strain of the virus.
The combination of a higher viral load, the ability to spread the virus to others earlier (when people may not realize that they’re sick) and the fact that this variant spreads more efficiently makes the Delta variant worrisome. The CDC has classified it as a “variant of concern,” which is a term that’s used when a virus is more transmissible, causes more severe disease or involves other complications.
- People who are infected with the Delta variant may get sicker. Recently published research from Scotland has shown that unvaccinated people who are infected with the COVID-19 Delta variant are twice as likely to be hospitalized, due to severity of illness, than people who are infected with the COVID-19 Alpha variant, which had previously been identified as more contagious than the original strain of the virus. More research is needed to determine whether the Delta variant causes more severe illness than other strains, but the presence of a higher viral load may contribute to more symptoms among affected people.
- COVID-19 vaccines offer the best protection against the Delta variant. The current research suggests that the COVID-19 vaccines that are available within the U.S. offer protection against the Delta variant, although researchers will continue to study their effectiveness. Studies have shown that COVID-19 vaccines prevent symptomatic disease and hospitalization among the majority of people who are exposed to the Delta variant.
The CDC recommends that people who aren’t vaccinated should get the COVID-19 vaccine to protect themselves from the risk of illness from COVID-19, including the Delta variant. In the event that someone who is vaccinated gets COVID-19, the vaccines protect against the severity of illness, which helps to prevent hospitalization and death.
For those who aren’t vaccinated yet – including those who are not yet eligible – other ways to help protect against the Delta variant include:
- Wearing a mask over your nose and mouth while you’re spending time around people from other households, especially when you’re in poorly ventilated indoor spaces or crowded areas
- Staying 6 feet away from people who aren’t part of your household
- Washing your hands frequently (or using hand sanitizer when soap and water aren’t available)
- Steering clear of crowded indoor spaces, including poorly ventilated ones
- Paying attention to local COVID-19 infection rates, including Delta variant rates, and avoiding unnecessary social contact with others when infection rates surge
Next Steps & Resources:
- Meet our sources: Barry Kreiswirth, Ph.D., member of the Hackensack Meridian Center for Discovery and Innovation (CDI) and Jose Mediavilla, M.B.S., M.P.H., manager, Infectious Disease Lab, CDI.
- To make an appointment with a doctor near you, call 800-822-8905 or visit our website.
The material provided through HealthU is intended to be used as general information only and should not replace the advice of your physician. Always consult your physician for individual care.