The highly-transmissible COVID-19 delta variant is spreading fast, prompting some health officials and experts from the Centers for Disease Control and Prevention to once again recommend masks in crowded indoor settings for people who are fully vaccinated against COVID-19.

What should you do? If you’re fully vaccinated, should you wear your mask again indoors?

The answer is “yes” for many people, and certainly for anyone who feels more comfortable wearing a mask. Of course, individual circumstances make a difference when you’re deciding when to wear a mask. So, we reviewed specific scenarios with Dr. Michelle Barron, senior medical director of infection prevention and control for UCHealth and a professor of medicine and infectious diseases at the University of Colorado School of Medicine on the Anschutz Medical Campus. Barron is one of the top infectious disease experts in Colorado and also has coped with the loss of family members to COVID-19.

First, why is the COVID-19 delta variant so dangerous?

The delta variant is much more infectious than the original strain of the virus that causes COVID-19. Each person who contracted the original strain on average sickened about 2 to 3 other people. The delta variant, on the other hand, is almost twice as infectious. People infected with the delta variant are passing the virus on to about 4 or 5 other people.

“It’s huge. It’s the perfect storm,” Barron said. “Even if you don’t have a huge portion of the population who are infected with the delta strain, it can spread like wildfire. If you look across the U.S., rates of COVID-19 positivity are skyrocketing because the delta variant is so highly transmissible.”

To help drive down COVID-19 infections, leaders at UCHealth are now requiring all employees, medical staff, volunteers, students, vendors and contractors to get fully vaccinated against COVID-19.

“Providing the highest level of safety for our patients, staff and providers is always the top priority for UCHealth,” Barron said.

More and more employers and government entities are requiring vaccines to keep people safe. New York and California officials  announced vaccine mandates in recent days.

How can I stay safe from the delta variant?

The best way to stay safe from the delta variant is to get a free vaccine now to prevent COVID-19. Learn more about getting a free vaccine. The COVID-19 vaccines are safe and highly effective in preventing severe illness and hospitalization, even those from delta variant.

A small percentage of people who are getting sick with COVID-19 now have been fully vaccinated. But, the vaccines continue to work well against all strains of the virus that cause COVID-19.

Most of people who are getting breakthrough cases of COVID-19 (meaning they are getting infected after having been fully vaccinated) have suppressed immune systems. A new study by several experts, including Dr. Adit Ginde, an Emergency Medicine doctor at UCHealth University of Colorado Hospital, found that vaccines were highly effective in preventing hospitalizations for COVID-19. But, for immunocompromised patients, like transplant and cancer patients, the vaccines were effective about 60% of the time, lower than the 80 to 90% range for people with fully functioning immune systems.

What is the new guidance about the delta variant and masks from the CDC?

Due to increasing infections and hospitalizations related to the delta variant, CDC experts on July 27 reversed earlier guidance and recommended that people who are fully vaccinated against COVID-19 should once again consider wearing masks in indoor settings in parts of the country where the virus is spreading widely.

In addition, fully vaccinated people might choose to wear a mask regardless of the level of transmission in their community, particularly if they are immunocompromised or at increased risk for severe disease from COVID-19, or if they have someone in their household who is immunocompromised, at increased risk of severe disease or not fully vaccinated.

The CDC experts also are recommending that everyone in schools – from teachers to staff to students and visitors – should wear masks regardless of vaccination status or how widely the virus is spreading in their community. The priority among health experts is to provide in-person learning for all students.

What is happening in hospitals now? Who is getting sick?

Due to the highly infectious delta variant, the number of hospitalized patients in UCHealth’s 12 hospitals and in other hospitals throughout Colorado and the U.S. has been spiking since the recent low point in hospitalized patients in mid-June. Nearly all of the patients who are sick enough with COVID-19 to need hospital care now have not received COVID-19 vaccines.

In Colorado, according to new data from the Colorado Department of Public Health and Environment, 95% of all patients who have been hospitalized since January with COVID-19 had not received a vaccine.

In addition to getting a COVID-19 vaccine, what can I do to stay safe from the delta variant?

Wearing masks can greatly reduce the risk of spreading the delta variant. Masks and social distancing helped immensely in reducing the spread of the coronavirus before vaccines became widely available this year.

While most state and local officials have lifted mask mandates, some communities, like Los Angeles County, once again are requiring masks in indoor settings. This new mandate is aimed at keeping people safe and tamping down infections from the delta variant.

Should unvaccinated people wear masks?

Absolutely, Barron said.

“If people aren’t fully vaccinated and aren’t wearing masks, they’ve removed all the layers of protection,” she said.

Do I still need a mask in a hospital, clinic or on a plane?

Yes. Everyone who is in health care settings must wear a mask, even if you are fully vaccinated against COVID-19. And, masks are still required on airplanes and in airports.

If I’m fully vaccinated, should I consider wearing a mask again in crowded indoor settings like grocery stores, gyms, hair salons, restaurants and movie theaters?

The key to deciding whether to wear a mask again in crowded indoor settings is to assess your own risk and the risk of people with whom you live or have close contact.

“If you have vulnerable people in your home, even if they are fully vaccinated, you might want to wear a mask again,” Barron said.

The people most at risk are older adults and people with compromised immune systems such as those with chronic illnesses or transplant patients. The vaccines are protecting everyone, but they are not as effective for people with compromised immunes systems.

Also, families with children under age 12 who cannot yet get their vaccines may want to be cautious since the delta variant is spreading so widely. In general, children who get COVID-19 do not get as sick as adults. But, some children can get very sick and some can develop long-lasting symptoms, known as long COVID. COVID-19 can cause critical illnesses in people of all ages.

Barron, herself, is still wearing a mask in crowded, indoor settings.

“I’ve never stopped wearing a mask in the grocery store. I don’t wear a mask when I’m outdoors. I don’t wear a mask if I’m around fully vaccinated individuals,” Barron said. “But, if I go anywhere in a crowded environment, I wear a mask.”

Since Barron cares for hospital patients with compromised immune systems, she takes precautions to stay as healthy as possible.

“I want zero risk. I have an obligation to keep others safe,” she said. “For regular folks, you need to be aware of who is in your environment in indoor spaces.”

Do fully vaccinated people need to wear masks outside?

No. Very few infections have spread outdoors. So, fully vaccinated people should not need to wear masks outdoors.

What if I’m fully vaccinated and I’m socializing with fully vaccinated friends or family. Do we need masks?

No, fully vaccinated people are fine socializing without masks with other fully vaccinated people, as long as none of the people are trying to protect someone who can’t get a vaccine or a person who is immunocompromised, and therefore, can’t get the full benefit of the vaccine.

If vaccines are working so well, why are masks necessary?

“About 94% of people who are getting vaccines are not getting COVID-19 or not needing to be hospitalized. That is very good,” Barron said. “But, some people who are older or who have cancer, diabetes, lung disease or have had transplants, can get sick after getting a vaccine.”

For them, wearing masks may increase their protection, especially since the delta variant is so infectious.

“Masking is a very safe way to keep yourself healthy and a very simple way to protect others,” Barron said.

What do you think when you hear people say that the pandemic is over?

Unfortunately, the pandemic is not over, Barron said. It’s most certainly not over for people in other countries who do not have the same access people in the U.S. do to safe and highly effective vaccines. And, resistance among many Americans to getting vaccines is extending the pandemic and allowing variants like the delta strain to proliferate and spread.

“The pandemic is here and will continue to be here for the foreseeable future,” Barron said. “Vaccination is still the most important tool for protection. Even if you get COVID-19 after getting vaccinated, the vaccine will likely keep you from going into the hospital and from dying.”

And, wearing a mask can add another layer of protection for people who are at high risk.