During a recent White House briefing, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, noted that the data from the UK showed the vaccines are 88% effective at preventing people from developing symptoms.
Vaccinated people are eight times less likely to get sick and 25 times less likely to end up in the hospital compared to unvaccinated people, Fauci said.
For context, the CDC has documented a total of 6,587 cases of fully vaccinated people who were hospitalized or died from COVID-19, among the more than 163 million people who have been fully vaccinated in this country.
That is a rate of 0.01% or less, Fauci said.
"The bottom line of what we are saying is: Get vaccinated," Fauci says. "The COVID vaccines give strong protection against the delta variant, and it protects you, your family, and your community.
Though the CDC only tracks breakthrough infections that lead to hospitalization and death, some states are keeping track of every case. According to an analysis by the Kaiser Family Foundation — among states that track the data — the rate of breakthrough cases among fully vaccinated people ranged from 0.01% in Connecticut to 0.29% in Alaska.
What about long COVID-19?
While the risk of getting sick if you're vaccinated is very low, if you do get a symptomatic case, it's still possible to end up with long-haul COVID-19 symptoms, according to virologist Angela Rasmussen, who works with the Vaccine and Infectious Disease Organization at the University of Saskatchewan in Canada. She notes the data is still quite limited, though.
"Even if you don't end up in the hospital, there's certainly a possibility that you could end up with long COVID," she says. "So, the safest thing to do is to avoid being infected altogether."
In fact, a recent study from Israel suggested that even people who experience "mild" breakthrough infections may be at risk for symptoms that linger.
The study found that about one in five people — 19% — who got infected even though they were vaccinated experienced symptoms found in long COVID patients that lasted at least six weeks, including headaches, body aches, fatigue and loss of taste and smell. The study, however, was very small, including only seven patients out of about 1,500 who experienced lingering health problems.
Should I go back to wearing a mask in public?
Yes, and many experts advise you up your mask game to wear the best-fitting mask you can.
In late July, CDC issued new guidelines that even fully vaccinated people should start masking up again indoors when they are places where the virus is circulating widely. (Check this map with data from the CDC to see if you need to mask up where you live.)
The CDC's new recommendation was based on an investigation of an outbreak that occurred in Provincetown, Massachusetts, around the July 4 holiday. Researchers discovered that fully vaccinated people who caught the virus could carry as much virus as unvaccinated people, which means they could spread the virus to other people. The findings are consistent with outbreak investigations, the CDC's Walensky said.
The CDC also updated its guidance to recommend everyone in schools wear masks, regardless of whether they are vaccinated.
"I understand this is all frustrating news, and I share this frustration," Walensky said. "We continue to learn each day from emerging science and use this evidence to update our recommendations."
Before CDC changed its guidance, many health experts were already calling for vaccinated people to resume masking indoors. Many said they'd never stopped masking.
Bill Miller, a physician and epidemiologist at The Ohio State University says he wears a mask in public places, even though he's fully vaccinated. "I know that I am extremely unlikely to get seriously ill. But I also know that if I am exposed, I may become infected and pass it on to others," he says.
Do I need a booster shot?
At this point, no. So far, the federal government doesn't recommend booster shots to enhance immunity, though it is actively studying the question.
"The CDC and the FDA are working very hard to get as much data as they possibly can to adequately address that question," Dr. Fauci told NPR's Here & Now recently. Federal health officials and vaccine makers continue to follow participants enrolled in the initial clinical trials to see how well immunity holds up with current vaccinations.
So far, experts say it's encouraging. "The level of antibodies seem to be holding up pretty well, so we have to watch and see what happens over the course of the coming months," Francis Collins, National Institutes of Health director, told NPR in an interview.
Eventually, as immunity wanes, a booster could be recommended for certain groups, including elderly people. There's also research underway to test a mix-and-match approach to booster shots. Researchers are giving study participants who were originally vaccinated with any of the three authorized vaccines a booster shot of the Moderna vaccine.
White House COVID-19 response coordinator Jeff Zients said that the administration is ready for the possibility of boosters "if and when the science shows they are needed."
However, some other countries have either already started or announced plans to start giving very vulnerable or older people boosters soon.
What about kids? Can kids get infected and spread delta?
Yes. Although children tend to have milder cases of coronavirus, they are certainly susceptible to infection. Children remain the least protected age group, since the vaccine is not authorized for children under the age of 12.
It's possible that children who get infected with the delta variant might have more symptoms than they would if they were infected with an earlier version of the virus. With a more transmissible variant, "when someone gets sick, they tend to have more virus, and they tend to have more symptoms," Chu, from the University of Washington, explains.
That being said, typically "children are not that symptomatic from COVID," she says. Her best guess? She thinks delta "probably will not lead to significant numbers of children getting hospitalized."
But there's still a reason to keep your kids masked up in public, and that's the risk they could spread it to more vulnerable people, says Rasmussen, from the University of Saskatchewan. "Even if it doesn't impact them, it could impact other vulnerable people in their household, such as people who may not have had a robust response to the vaccine, people who are immunocompromised."
Is it safe to fly, especially with my unvaccinated kids? Any other travel precautions to be aware of?
Infectious disease experts say to use extra caution when traveling. "We are now dealing with a different virus, and we are living in this highly contagious virus' playground," Dr. Ravina Kullar, infectious diseases specialist and epidemiologist, at UCLA, told NPR via email.
Airplanes themselves are generally deemed low risk, given that the air filtration is typically excellent and passengers wear masks. But getting to, and waiting around in, the airport could be risky, especially for unvaccinated kids. With that in mind, Kullar says she would hold off on flying with young kids "until delta plateaus" and plan a road trip instead.
Other experts said short flights may be OK. But if you do fly, make sure you and your kids wear well-fitted masks, ideally N95s or KN95s, or double mask. And keep masks on the entire time you're in the airport and plane.
Whether you plan to fly or drive, take a look at the level of coronavirus spread in the area you're traveling to, advises Dr. Helen Boucher, an infectious disease physician at Tufts Medical Center. She suggests canceling plans to travel to places with high or "substantial" spread, according to the CDC designation. (Check NPR's map here.)
Dr. Jeanne Marrazzo, infectious disease specialist at the University of Alabama at Birmingham School of Medicine, agrees strongly: "One should be very wary of taking a child too young to be vaccinated from a low-incidence state to a high-incidence state like Florida," she told NPR. "Glad I don't have to make those hard choices for my family."
If you fly, there's "no need to quarantine after flying unless a person has symptoms," Dr. Tina Tan, an infectious disease specialist at the Northwestern University Feinberg School of Medicine, told NPR via email. But do avoid busy, crowded vacation spots, she warns. Other agree: Beach parties, bars and crowded concerts, even outdoor ones, could pose a risk during the delta surge.
Should I turn down invitations to weddings and other large gatherings?
Many public health experts say it's safe to attend certain gatherings if you're vaccinated, but keep the variant in mind, especially if you're somewhere with rising cases.
OSU's Bill Miller says he encourages mask wearing for an indoor wedding or event "because you're bringing people together from different social networks, creating a great opportunity for an outbreak."
One case study serves as a reminder that the risk is not zero: Six vaccinated people got COVID-19 after attending a wedding near Houston, held in a large, outdoor tent. All of the infected people got symptoms, one was hospitalized, and another person — who had received India's Covaxin vaccine — died, according to a preprint study.
As scary as that sounds, "there could be rare events like these where people are in an enclosed tent and very close to each other. But the vast majority, the vast, vast majority of viral transmission is happening indoors," says Chu.
Does delta cause different COVID-19 symptoms?
Maybe. Some doctors and public health departments have reported that people infected with delta have different symptoms from the original, classic signs of COVID-19: cough, loss of taste or smell, and fever. Now, some of the more common symptoms appear to be runny nose, sore throat and headache, according to the ZOE COVID Study, an ongoing app-based research project based in the UK.
But Chu warns that it's hard to know what's behind that apparent change, "because the population that it's infecting is not the same population that was infected in the prior waves." The people getting sick now tend to be much younger, she says.
Since COVID-19 might present differently in younger people, any changes in symptoms could have less to do with the new variant and more to do with the people who are contracting it. "I don't know that you can disentangle that," Chu says.
"This is already a disease that produces a pretty broad range of different clinical presentations in people," adds Rasmussen. She'd like to see better data before concluding the symptoms are, in fact, different.
Do I need those bleach wipes again?
No extra surface cleaning is necessary. Even though it's more transmissible, delta still transmits the same way the original SARS-CoV-2 virus does. "This type of virus, which is an RNA virus that is enveloped, tends to transmit [through] respiratory transmission," Chu says.
That's backed by "some extremely detailed contact tracing" done in the recent preprint study from China, says Rasmussen. The researchers "determined that these cases were transmitted primarily through what they called indirect contact, which is most likely inhalation of infectious aerosols [while] breathing shared air, or through direct physical contact," she says.
That means the virus is most likely to be transmitted to someone indoors who is breathing in a nearby infected person's droplets or aerosols. With delta, the difference is that the infected person will make many more copies of the virus, faster, which makes it easier to spread.