At a particularly crucial juncture in the pandemic, the Centers for Disease Control and Prevention has a messaging problem.
The CDC and its director, Dr. Rochelle Walensky, have been the subjects of growing criticism over statements and guidance that have been revised or walked back.
The U.S. faces something of a conundrum. Millions of Americans are getting vaccinated every day, and state and local governments are relaxing restrictions. Meanwhile, as case numbers rise in parts of the country, public health experts worry about the possibility of a fourth surge.
There are no easy answers.
"One of the most important things we say in public health is that you have to have a very simple message," said Dr. Wafaa El-Sadr, a professor of epidemiology and medicine at Columbia University. "But we're in a situation where the message is very complex."
The problems started last week with what were perceived as mixed messages about the state of the pandemic and what's safe for people who have been fully vaccinated.
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Walensky warned March 29 of "impending doom" because of recent increases in case numbers across the country. In an interview with MSNBC the same day, she raised eyebrows by suggesting that "vaccinated people do not carry the virus." Many researchers criticized the comments, saying it's too soon to know for certain what effect the vaccines may have on transmission. The CDC walked back her statement a few days later.
The agency then relaxed its travel guidance for people who are fully vaccinated, but in light of the steady rise in case numbers and the fact that majority of the U.S. population is still unvaccinated, Walensky said, "I would advocate against general travel overall."
The recent back-and-forth caused confusion and frustration, and it muddied public health messaging at what some experts say is a precarious moment. The CDC is being criticized at a shaky time as it tries to rebuild trust that has eroded over the past year, largely because of political interference from the Trump administration.
"Whether you're a public health agency or doing a communications campaign of any kind, an erosion of trust is incredibly damaging," said Alison Buttenheim, an associate professor of nursing and health policy at the University of Pennsylvania.
She said Walensky's comments about vaccinated people and transmission were "not super thought-out," but she added that missteps in public health messaging can be rescued if they are handled transparently.
Others have been less sympathetic.
"CDC messaging on restrictions post vax has been a mess," tweeted Dr. Vinay Prasad, an associate professor epidemiology and biostatistics at the University of California, San Francisco.
The missteps highlight the enormous challenges of public health messaging during the pandemic, when the science is unfolding in real time and developments often happen at breakneck pace. Crafting public health guidance under such circumstances makes it hard to address the nuances, especially as the pandemic evolves and the situation shifts.
"People want an answer that is black or white: Is this risky or not risky?" said Sandra Albrecht, an assistant professor of epidemiology at Columbia University. "But risk is a spectrum — it depends on the context, the circumstance, the individual, geography. There are so many factors that contribute to risk that it's really hard to deliver one line of public health messaging for everyone."
And conversations about risk become more challenging as "pandemic fatigue" sets in. A newly released Gallup poll found that concerns about contracting the coronavirus have fallen to record lows, with only 35 percent of Americans saying they are very worried or somewhat worried about catching the virus.
Albrecht and Buttenheim saw the difficulties of communicating risk and guidance early on in the pandemic. Last year, they teamed up to create Dear Pandemic, an online project to answer questions from the public in an easily digestible way and help people navigate the onslaught of information about Covid-19.
One of the project's main goals is to fill the gaps between official guidance with facts and context.
"A lot of what we've done is discuss the reasons and the motives behind public health messaging that comes from the CDC, because the public is left confused," Albrecht said. "Part of what we do is explain the rationale and evidence to support a certain line of recommendation."
Early in the pandemic, for instance, Albrecht and Buttenheim tried to address why the CDC and the World Health Organization reversed course on recommendations for people to wear masks in public.
"As scientists and public health professionals, we understood why that change happened and why it was necessary, but the reasons for that change were not adequately delivered to the public," Albrecht said. "That caused a lot of confusion and gave fodder to conspiracy theorists."
Loren Lipworth, an epidemiologist at Vanderbilt University Medical Center, said the events of the past year have laid bare how important it is for the CDC and public health professionals to be open about where the science stands and to manage people's expectations about how things can change.
"The CDC should be honest and transparent and share everything they can in terms of evaluating the evidence, but they also need to be appropriately cautious when we're at a point where we can't say something yet," she said.
The balance is especially important now, when upticks in infections in some states threaten to erase hard-fought gains to stem the virus's spread.
And as case numbers rising and variants of the virus spread around the country, how people and communities respond in the coming weeks could alter the trajectory of the pandemic in the U.S., Lipworth said.
"We're so lucky to have these vaccines, and that's definitely our way out, so there's real cause for optimism ahead of us," she said, "but this is definitely not the time to let down our guard."