COVID-19 is likely to follow a seasonal pattern — similar to some other respiratory viruses — with fewer cases come summer 2021 followed by a jump next winter, experts predicted in a briefing Thursday.
If that pattern holds, it could mean a need to reinforce the mask-wearing message as the weather gets colder and people once again congregate indoors.
"Right now, we are projecting the United States all the way to Aug. 1 [will have] 619,000 deaths from COVID-19, with 4.7 million globally," said Ali H. Mokdad, PhD, a professor at the Institute for Health Metrics and Evaluation (IHME) at the University of Washington in Seattle, during the briefing sponsored by the Infectious Diseases Society of America (IDSA) and IHME.
As of Friday morning, more than 570,300 Americans had died of COVID-19, 3.07 million worldwide, according to Johns Hopkins University.
The encouraging news is the vaccines appear to be working and more Americans are getting them. "If you look at the data for these vaccines, they are extremely safe, they are extremely efficacious, and they make you basically impervious — for the most part — to getting serious disease, hospitalization, or death," said Amesh Adalja, MD, senior scholar at Johns Hopkins University Center for Health Security in Baltimore."These vaccines do what they were meant to do: defang this virus," Adalja said. New data out of Israel and other countries suggests a vaccinated person is less likely to transmit the virus as well, he added.
Still Aiming for Herd Immunity
Furthermore, the FDA is likely to approve emergency use authorization (EUA) among teenagers 12 to 15 years old " at any moment, expanding the pool of people protected by vaccines.
Such authorization could help with overall public health efforts. "That's simply a mathematical formula," Adalja said. "The more people that are vaccinated, including children, the quicker we'll get to herd immunity."
In addition, with lower case numbers expected this summer, herd immunity might become more achievable, said Mokdad, who is also chief strategy officer for population health at the University of Washington.
As important as herd immunity is, so-called decoupling is "more important to me," Adalja said. Decoupling refers to separating infections from the more severe outcomes, so people who get COVID-19 are less likely to need hospitalization or die from it.
Vaccines get the credit here, he added, including with the variants. "Even if you get a breakthrough infection (after you’re vaccinated) with a variant, it's not likely to land you in the hospital or cause serious disease or death," Adalja said.
Masks and the Uncommon Cold
Wearing a mask until we reach herd immunity is important because it's not possible to tell who is vaccinated and who isn't, Mokdad said. "Remember, as many people are waiting to get a vaccine, all of us have access to a mask," he said.
Adalja agreed, adding that public health guidance on masks will likely stay in place until we cross that herd immunity threshold and community circulation of the virus goes down.
"People are probably going to want to continue wearing masks, at least some proportion, because they see the benefit for other respiratory viruses," Adalja said. "How many of you had a common cold this year?"
Variants: Some Good News?
Experts are monitoring the spread of variants of concern in the U.S. and abroad. On a positive note, the B.1.1.7 variant first identified in the United Kingdom appears to be dominant in the U.S. at this time, which is potentially good for two reasons. One is that the available COVID-19 vaccines appear to be working against the strain, Mokdad said.
Second, a predominance of B.1.1.7 makes it more difficult for other emerging variants of concern like P1, first seeni n Brazil, or B.1.351, which first emerged in South Africa, to gain control, Adalja said.
"B.1.1.7 is such an efficient transmitter," he said. "That's kind of an advantage…because the more B.1.1.7, you have the less opportunity B.1.351 and P1 have to set up shop."
Hesitancy From Misinformation
Vaccine hesitancy remains a concern, particularly at a time when some predict a drop in the number of Americans seeking vaccination. Although needle phobia plays a role in dissuading some from vaccination, the bigger issue is vaccine misinformation, Adalja said.
"Some people are just terrified when they see the needle. That's a small part of the proportion of people who don't want to get vaccinated," Adalja said. In contrast, he attributed most hesitancy to misinformation about the vaccine, including reports that the vaccines are fake.
Even celebrities are getting drawn into the misinformation.
"I just had to answer something about Mariah Carey's vaccination," he said. Someone believed "that it was done with a retractable needle that didn't really go into her arm."
Vaccine hesitancy is more about people not understanding the risk-benefit analysis, taking side effects out of out of context if there are side effects, or being influenced by "arbitrary statements about microchips, infertility, or whatever it might be," Adalja said.
The Future Is Subject to Change
"We're expecting another rise in cases and more mortality in our winter season here in the United States," Mokdad said, adding that the efficacy of the vaccines is likely to attenuate the mortality rate in particular.
However, as the epidemiology of the pandemic evolves, so too will the long-term predictions. Factors that could influence future numbers include the expansion of vaccination to teens 12 to 15 years old and (eventually) younger children, a need for booster vaccines, emerging variants, and the changing proportion of the population who are fully vaccinated or were previously infected.
Again, getting people to adhere to mask wearing come winter could be challenging if the scenario over the summer is "close to normal with less than 200 deaths a day in the United States," he added. Asking people to wear masks again will be like "swimming upstream."
"I think it's a mistake to think that we're going to get to 'COVID zero,' " Adalja said. "This is not an eradicable disease. There's only been one human infectious disease eradicated from the planet, and that's smallpox, and it had very different characteristics."