By Faye Flam / Bloomberg Opinion

Covid-19 was already spreading widely around the world in February and early March of 2020 – well before many Americans had gotten the message that the disease was something to take seriously.

Now, The New York Times has reported that staffers at the disease intelligence service at the Centers for Disease Control and Prevention were pressured by the Donald Trump administration to keep silent about what they knew: that covid was being spread quietly by asymptomatic carriers.

These allegations go to the heart of the challenge facing public health officials today: Many people no longer trust them to give fact-based, unbiased, non-politicized advice. Earlier this month, a survey of more than 4,000 Americans led by Harvard researchers and published in the journal Health Affairs showed that only 37 percent said they still had a great deal of trust in CDC. The rest answered that they either trusted CDC somewhat, not very much, or not at all, and among those, 74 percent cited political influence on the agency’s recommendations and policies.

These numbers show how far the agency has to go to rebuild trust; something that will be even harder than reorganizing the agency, as director Rochelle Walensky has been doing.

To understand the scale of the challenge at the CDC, we need to go back to early 2020. Back then, scientists were already putting the major pieces together; that despite the deadliness of the virus for some people, many cases were barely symptomatic; that these barely symptomatic people could easily transmit the virus; and that the disease might be airborne; contaminating indoor air sometimes more than six feet from any infected person.

The CDC should have been shouting these facts from the rooftops, but it wasn’t.

The White House attempted to give daily press briefings, but these were notoriously unhelpful, sprawling and disorganized. Prescient warnings like the one from CDC official Nancy Messonnier in late February 2020 were contradicted by the executive branch or walked back by other CDC officials. The White House announced in March 2020 that Vice President Mike Pence would be controlling messages out of the agency, when we needed the opposite to happen; the CDC should have been vetting statements from President Trump and Pence for accuracy, rather than letting the White House censor scientific facts.

In the information vacuum, news outlets amplified studies that many experts at the time found misleadin; playing up minuscule transmission risks associated with contaminated surfaces or outdoor activities. Though there was a legitimate, early concern about transmission from surfaces, virologists argued that whatever tiny traces remained hours or days after something was touched were extremely unlikely to infect anyone.

Meanwhile, asymptomatic spread deserved more attention. The first clues that it could happen came in late January and February of 2020 from scientists in Germany and Singapore, where outbreaks were identified earlier and where there was better testing and contact tracing. So scientists knew it could happen; but they continued to debate how often infected people remained symptom-free and how infectious they were. In the absence of decisive leadership from the CDC, the debate played out in Twitter threads and op-eds, perhaps leaving the public with the impression that the basic fact of asymptomatic spread was disputed. It wasn’t.

In March of 2020, I interviewed Jeffrey Shaman of Columbia University School of Public Health to try and clear up the confusion. He’d worked on a Science paper on the rapid but stealthy spread of the disease. He told me that I was getting too hung up on whether people with covid were subtly symptomatic, asymptomatic, or pre-symptomatic; what mattered was that the disease was spreading silently, cryptically, under the radar.

Perhaps CDC officials would have been quicker to hammer that point home had the Trump administration not leaned on them to keep mum. Had they been more vocal, people might have demanded more action; especially more testing. As I pointed out in March 2020, we desperately needed the kind of widespread testing that was flagging mild or asymptomatic cases and mitigating the spread in other countries.

Alessandro Vespignani, a network expert at Northeastern University, created models that showed, back in the first quarter of 2020, that the virus was already rampant in both the U.S. and Europe. It was too late for travel restrictions to be likely to help. What we needed was widespread testing and contact tracing, as China, Singapore, South Korea and Japan were already doing. But in the U.S., tests were hard to come by; and mostly reserved for people who were sick and had traveled from China.

And as all this was happening, the U.S. government was trying to reassure the public rather than help us prepare. No wonder people have lost faith in public health officials.

That loss of trust has cost us dearly. It’s now well documented that despite U.S. advantages in pandemic preparedness, we suffered far more deaths per capita than other wealthy countries. Countries with high levels of trust, like Denmark and Sweden, managed fewer deaths while also imposing fewer restrictions and suffering less educational and economic disruption. In the United Kingdom, public trust in the vaccination campaign allowed that country to overcome early pandemic fumbles and reduce excess deaths in subsequent waves of infection. Not in the U.S., where the Omicron wave devastated less-vaccinated states.

It’s true that during the early weeks of 2020, the CDC had other problems beyond political interference. In February, the agency made headlines for bungling a test for the new virus, even as other countries were already employing sophisticated testing and contact tracing schemes. And most of the statistics people received on caseloads were coming not from the CDC but from volunteer efforts put together by the Atlantic and the New York Times. Walensky’s reorg may be most effective in solving some of these sorts of issues.

But deeper change will likely be needed if the agency is going to stay strong against the meddling of the executive branch. And the White House will often be tempted to influence CDC recommendations, as we’ve seen with the Biden administration’s impact on booster guidance.

Policy should be informed by science and formed by the will of the people. For that to work, the public needs a clear picture of what we’re up against. It’s the CDC’s job to paint that picture; despite whatever the current occupant of the White House would like to hear.

Faye Flam is a Bloomberg Opinion columnist covering science. She is host of the “Follow the Science” podcast.