What to know about the delta variant: Infectious disease experts weigh in

July 17, 2021 Swedish Health Team

Key takeaways:

  • The highly infectious delta variant now makes up the majority of COVID-19 cases in the U.S.
  • This variant spreads quickly among unvaccinated individuals and is causing more severe illnesses than the previous variants.  
  • Vaccines offer lifesaving protection against COVID-19, including the delta variant.
  • Masking, physical distancing and hand hygiene can help reduce individuals’ risk of becoming sick. 


As vaccines for COVID-19 became readily available in the U.S., many of us were able to return to the activities we missed:

Seeing family and friends.


Celebrating birthdays and holidays with loved ones.

We’ve been able to enjoy loosening restrictions in our communities, yet at the same time, we must remain vigilant as mutations like the delta variant begin to spread. Questions remain:   

Do I need to wear a mask if I’m vaccinated?

Who is the most at risk of the delta variant?

How can I keep myself and my family safe and healthy?

Do vaccines protect against the Delta variant?

How do I handle social settings with my unvaccinated kids?

Evan Sylvester, MPH, regional director of infection prevention at Swedish, shares the facts about the COVID-19 delta variant, how you can reduce your risk of becoming sick, how to protect unvaccinated people in your home and why vaccination is safe, effective and our path to ending the pandemic.

Understanding the delta variant

It’s common for any virus to mutate. It’s often those changes that make it easier to spread and infect more individuals – a virus’ ultimate goal. The delta variant is just one of the many mutations we’ve seen of COVID-19.

The delta variant was first detected in India in Dec. 2020. Currently, the Centers for Disease Control and Prevention (CDC) estimates that the Delta variant accounts for 51.7% of new cases – making it the most common strain in the U.S.

Sylvester explains that Washington state is seeing a similar increase in delta transmissions.

“In the last 30 days, the delta variant reached 39% of COVID-19 cases circulating in Washington. In the past few days, that percentage has gone up to nearly 50%. We expect that increase to continue,” he says.

One recent study suggests this delta variant is more infectious and spreads more readily.

“One recent study suggests this variant is more infectious and spreads more readily. Individuals infected with the virus have one thousand times more copies of the virus in their respiratory tract,” Sylvester explains.

Simply put – when you’re infected with the COVID-19 delta variant, you have more of its “germs” (viral load) in your body and are able to spread it earlier in your illness – often before you even realize you are sick.

“A recent study showed that the delta variant was twice as likely to result in hospitalization within unvaccinated individuals compared to the previously circulating variants,” explains Evan. “Additionally, we are starting to see a slight variation in presentation of symptoms between the delta variant and previous variants. Individuals with this strain are less likely to experience loss of smell or cough.”

More common symptoms include headache, sore throat, runny nose and fever.

Vaccine protection against the delta variant

The three vaccines available authorized for emergency use by the U.S. Food & Drug Administration (FDA) do offer protection against the Delta variant. In fact, 99% of the individuals who died from COVID-related causes in June were unvaccinated. Although this is a startling and somber statistic, it does paint a picture of the safety and efficacy of the vaccines.

“We know the vaccines reduce severe disease, hospitalization and death from the delta variant,” Sylvester states.

Even with vaccinations, some fully vaccinated individuals may occasionally become infected with the delta strain. These are called “vaccine breakthroughs.” Fortunately, these people have a lower viral load, which makes them less likely to become severely ill or spread it to others.

Slowing the spread of COVID-19 is key to protecting loved ones who are unable to get vaccinated – including children.

Still on the fence about getting a COVID-19 vaccine? Get the facts.

Protecting the unvaccinated

People ages 12 and up are eligible for the Pfizer COVID-19 vaccine, and the Johnson & Johnson and Moderna vaccines are available for people ages 18 and up. But there are still some groups that are unable to get the vaccine – those under age 12 or who have had a severe allergic reaction to ingredients in the vaccines.

Fortunately, experts hope a vaccine will be approved for emergency use in children between the ages of 5 and 12 early this fall.

Fortunately, experts hope a vaccine will be approved for emergency use in children between the ages of 5 and 12 early this fall.

If you have a member of your family who is not yet vaccinated, there are steps you can take to reduce your loved one’s risk of becoming sick with COVID-19 – precautions that you are already familiar with:

  • Wear a mask. The CDC recommends that all unvaccinated individuals ages 2 and up wear a mask in indoor public spaces and outdoor crowded areas. And in Washington state, a new indoor mask mandate went into effect on Aug. 23, 2021. 
  • Practice social distancing. Encourage children and loved ones to stay at least 6 feet away from unmasked teens and adults when you’re unsure about vaccination status.
  • Wash hands regularly. Good hand hygiene continues to be an important line of defense in keeping your family healthy from all germs and bacteria. Wash for at least 20 seconds or use a hand sanitizer when a sink is unavailable.
  • Quarantine immediately if exposed. It’s important to quarantine for 14 days as soon as you are aware of a COVID-19 exposure – even before you test positive or have symptoms of illness.

Play it safe

It’s understandable to feel overwhelmed about new information about COVID-19 and vaccines. What we do know has held true from the beginning of the pandemic:

  • Masks, hand washing and physical distancing can slow the spread of the virus.
  • Vaccines are a safe and effective way to keep you and your loved ones healthy.
  • COVID-19 can lead to serious and long-term health complications.

Find a COVID-19 vaccination clinic near you

To locate a vaccination site near you, visit the Washington State Department of Health Vaccine Locator website or call the Washington State Department of Health at 1-800-525-0127 and press #.

We encourage everyone who is eligible and able to get the vaccine to do so. Please continue to wear your mask, practice physical distancing and wash your hands frequently.


Find a doctor

If you have a question about COVID-19 or vaccines, please let us know. We’re here to help you make an informed and educated decision you are confident with.

Whether you require an in-person visit or want to consult with a doctor virtually, you have options. Swedish Virtual Care connects you face-to-face with a nurse practitioner who can review your symptoms, provide instruction and follow-up as needed. If you need to find a physician, caregiver or advanced care practitioner, you can use our provider directory.

Find out the latest updates on how we’re handling COVID-19.

Related resources

Lifting COVID-19 restrictions: Q&A with Swedish experts

Updated COVID-19 safety guidelines for fully vaccinated people

Still on the fence about getting vaccinated?

Tackling COVID-19 hot spots: More than 9,000 vaccines administered

This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

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