Dangers of Delta, a Summer Surge, and Masks: One Expert's Take

Damian McNamara

July 19, 2021

Of the many questions that continue to circulate about the COVID-19 pandemic, what the future holds with the Delta variant is likely one of the most prevalent. 

"If you're vaccinated, you should not worry about the Delta variant. If you're not vaccinated, you are really in trouble because it is likely that you will get infected," Carlos del Rio, MD, said at a media briefing today sponsored by Emory University in Atlanta.

In the past 2 weeks, US COVID-19 cases increased by about 140% and hospitalizations and deaths are up approximately 30%.

"The pandemic is not over," del Rio said. The global death rate now exceeds 4 million, including 1.8 million deaths last year. "More people died in the first 6 months of 2021 that in the entire year of 2020."

Dr Carlos del Rio

He attributed the rise in cases, hospitalizations, and deaths to the Delta variant. "I want to emphasize the Delta variant is incredibly infectious, highly transmissible," said del Rio, professor of medicine, epidemiology, and global health and executive associate dean of Emory University School of Medicine at Grady Health System.

To put the higher transmission in perspective, each person infected with the original SARS-CoV-2 virus was likely to infect 2.5 to 3 others. Someone infected with the Delta variant is likely to infect eight or nine people, who in turn can infect another eight or nine people, and so on, triggering exponential spread.

Most of the growth is occurring in places with low immunization rates, such as Arkansas and Missouri, but it's also beginning to impact Tennessee, Alabama, Georgia, and Florida, he said.

"Please, if you haven't gotten vaccinated, get vaccinated because that is the best protection you have against this very transmissible Delta variant." The best time to get vaccinated was 1 month ago; the second-best time to get vaccinated is today, del Rio added.

New Cases in Young Adults

Because vaccination was prioritized for people over age 65, risks of infection and severe outcomes are lower in this group, del Rio said. The higher risk group is now younger people who may have thought, "Oh this is no big deal. I'll get infected and that's that," he said.

The biggest increases in cases are among people ages 29 to 40 who are not vaccinated, del Rio added.

The Delta variant has not led to higher case numbers among children too young to get vaccinated, he said. "Because it's more transmissible, they're more likely to get infected. But we have not really seen a huge increase in cases among very young children, children under 12."

Mask Up Even if Not Mandated?

"I was recently down in Miami, Florida where they have a significant surge in cases," del Rio said. "And again, you go to the grocery store, who's wearing masks? People my age, people in their 60s, people that likely are all vaccinated. Who's not wearing masks? Young people who are likely people who are not vaccinated."

Del Rio recommends everyone wear a mask indoors in public places, even if fully vaccinated.

Asked his opinion of the CDC dropping its mask recommendations for the fully vaccinated, del Rio said, "the principle behind what they did…was very good and I fully support it. The implementation is what's a challenge."

"My observation has been that, unfortunately, the CDC recommendation became an excuse for people not to wear masks."

During the briefing, del Rio also said that the evidence does not support that fully vaccinated people who develop a "breakthrough infection" are at risk for long COVID illness. Furthermore, people with natural immunity to SARS-CoV-2 from a previous infection should likely wait about 3 months and then get vaccinated, as he's recommended to relatives, he said.

"Natural immunity is actually pretty good, but it is not as good as vaccination."

The Summer of Delta?

Although the pandemic has proven unpredictable so far, del Rio said. "This Delta variant is so quickly transmissible that I expect over the summer we're going see a surge and then it's going to come down.

"But they'll be other variants coming and they'll be other changes coming."

What happens in the fall "is going to depend on what happens with our vaccination rates," he said.

The vaccines are "amazing," del Rio said. "I just continue to be astonished at seeing people who are unvaccinated."

During a recent hospital service, "every single person I saw hospitalized with COVID had not been vaccinated," he said. "At the end of the day, we have to do a better job of convincing our communities about the benefits of vaccination. If we do that, we will not be dealing with this problem [like we are] right now."

Based on a July 19 media briefing sponsored by Emory University.

Damian McNamara is a staff journalist based in Miami. He covers a wide range of medical specialties, including infectious diseases, gastroenterology, and critical care. Follow Damian on Twitter:  @MedReporter.

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