As the United States reported more than 600,000 new Covid-19 cases in a week for the first time ever, US Centers for Disease Control and Prevention (CDC) Director Dr. Robert Redfield tweeted on Wednesday, “Now is the time to develop a testing strategy to maximize our ability to identify the silent epidemic of asymptomatic COVID-19 infections.”
Redfield’s tweet described a weekend meeting with fellow White House Coronavirus Task Force member Dr. Deborah Birx and Utah Gov. Gary Herbert to discuss testing and mitigation efforts in Utah. On Tuesday, Utah was among 21 states that saw their peak seven-day average for new daily cases.
In a reply to CNN about Redfield’s comment, Dr. Thomas Tsai of the Harvard Global Health Institute wrote in an email, “The time to develop a national testing strategy to identify asymptomatic COVID-19 infections was a few months ago, but that ship has sailed. Now is the time to implement a testing strategy focused on screening of asymptomatic individuals.”
By the CDC’s estimate, 40% of people with Covid-19 are asymptomatic.
The CDC came under fire in August after the agency’s recommendation was changed to read: "If you have been in close contact (within 6 feet) of a person with a COVID-19 infection for at least 15 minutes but do not have symptoms, you do not necessarily need a test unless you are a vulnerable individual or your health care provider or State or local public health officials recommend you take one."
At the time, the change was heavily criticized by doctors and health agencies who worried the agency was influenced by the White House. In September, the agency’s site was updated again to say that anyone who has been in close contact with someone who has Covid-19 should be tested, even if they don’t have symptoms.
"Due to the significance of asymptomatic and pre-symptomatic transmission, this guidance further reinforces the need to test asymptomatic persons, including close contacts of a person with documented SARS-CoV-2 infection," it says, calling the change a clarification.