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The Centers for Disease Control and Prevention on Thursday broadened its warning about who is at risk of developing severe disease from Covid-19 infection, suggesting even younger people who are obese or have other health conditions can become seriously ill if they contract the virus.

The new advice, timed to influence behavior going into the July 4 weekend, came as CDC Director Robert Redfield acknowledged serology testing the agency has conducted suggests about 20 million Americans, or roughly 6% of the population, has contracted Covid-19. Redfield said for every person who tests positive, another 10 cases have likely gone undiagnosed.


While the 20 million estimate is far higher than the figure on the CDC’s Covid-19 website, it still represents a fraction of the country’s population, Redfield said.

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“This pandemic is not over. The most powerful tool that we have, a powerful weapon, is social distancing,” he insisted during a press conference, only the second the CDC has been allowed to conduct since early March.

The new advice frames the risk as rising with age, jettisoning earlier warnings that mainly those 65 and older faced higher risk. It also puts greater emphasis on the risk presented by a number of health conditions, including having a body mass index of 30 or over. Previously the warning related to people who had a BMI of 40 or over.


“Younger people are in no way completely immune to the effects of SARS-CoV-2 nor are they at zero risk of severe manifestations,” said the Jay Butler, incident manager for the CDC’s Covid-19 response. “And among young people, that risk is elevated in those with underlying illness or health conditions, including things like diabetes or obesity.”

The agency is also warning that being pregnant may increase a woman’s risk of being hospitalized and having a severe bout of the illness, based on a study of more than 8,000 pregnant women in the United States who were diagnosed with Covid-19.

The study, published in the CDC’s Morbidity and Mortality Weekly Report, an online journal, found that pregnant women were 50% more likely to be hospitalized with Covid-19 than infected women who weren’t pregnant and had a 70% greater chance of needing mechanical ventilation than non-pregnant women with the infection.

But the study did not find an increased risk of death among the pregnant women.

The new guidance reflects what has been apparent for months now, with countless new severe cases among young people and those with underlying conditions. But warnings of those cases have largely gone unheeded as states have begun to reopen.

The country is seeing a fresh surge of cases, particularly in the West and South, where hospitals are swelling with new cases and state governments are struggling to respond. On Thursday, Texas Gov. Greg Abbott announced the state would pause its reopening in the face of outbreaks across the state.

Despite the surge in cases, President Trump has continued to express the view that the virus is going away. When asked if Americans were getting mixed messages about whether they need to take precautions to prevent becoming infected, the CDC director appeared to seek a middle ground.

Redfield suggested many of the infections now being diagnosed would have been missed earlier in the pandemic, when testing was less common.

“I’m asking people to recognize that we’re in a different situation today than we were in March, in April, where the virus was being disproportionately recognized in older individuals with significant comorbidities and was causing significant hospitalizations and deaths,” he said.

“Today we’re seeing more virus. It’s in younger individuals. Fewer of those individuals are requiring the hospitalizations and having a fatal outcome. But that is not to minimize it.”

But Redfield went on to note that descriptions of the state of the pandemic in the country can be misleading, with maps that show where transmission is high suggesting much of the nation is experiencing high levels of spread. In reality, he said, about 110 or 120 counties in the country currently have significant transmission. There are more than 3,100 counties in the United States.

The new guidance breaks down medical conditions that can influence disease severity into those for which there is strong evidence, and those for which the evidence is not as strong, classifying the latter as conditions that might increase the risk of severe illness.

Cardiovascular disease, chronic kidney disease, chronic obstructive pulmonary disease or COPD, obesity, any immuno-suppressing condition, sickle cell disease, a history of an organ transplant, and type 2 diabetes are classified as having strong evidence of increasing the risk of Covid-19 infection.

Conditions that are considered ones that might increase the risk of severe illness are chronic lung diseases, including moderate to severe asthma and cystic fibrosis, high blood pressure, a weakened immune system, neurologic conditions, such as dementia or history of stroke, liver disease, and pregnancy.

  • Where does the CDC stand on vitamin D supplementation? There is a lot of evidence which suggests that enhancing our immune system with vitamin D would significantly reduce the fatality rate of this virus.

  • I would really appreciate the raw data. The conclusions drawn are fine, but the actual number of deaths on a weekly basis is where the real information lies. I could see the increase/decrease in deaths and draw my own conclusions. A chart with the death/hospitalization rate per state per week would be extremely useful information.

    • Agree! Deaths seem to be the only reliable benchmark of the virus penetration into a population.

      Surprised that blood type was not included in this article or the CDC guidelines. Didn’t a recent study indicate that risk of serious complication is 50% higher in those with blood type A?

  • I do not know why the media, and ALL the media, does not report the new 20 M infected or previously infected as the biggest, and best, news since the start of this.
    Doesn’t it mean a much lower case fatality rate? And, maybe not herd immunity, but much greater resistance to the epidemic, at least in places where there are a lot of people with antibodies?
    It seems like very good news, but is barely a blip in the media. What gives?

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