COVID-19 Pandemic Response

Patients Help Map Steps to Preventing COVID-19

On March 5, 2020, in the early days of the COVID-19 pandemic, Colorado reported its first case of COVID-19 in an international traveler on a ski holiday.

Graphic of a face mask with words representing the different characteristics investigated in a COVID study.

Disease detectives created this word cloud mask to show types of characteristics they investigated.

Colorado health officials were monitoring the global situation and knew they needed to quickly inform the public about how to reduce their risk of COVID-19. A thorough understanding of the potentially deadly disease was critical for health officials making decisions about preventive measures and for healthcare providers caring for the sick.

Colorado is one of only a handful of U.S. states besides Georgia with a CDC office. Typically devoted to preventing and controlling germs spread by ticks, mosquitoes, and fleas, the CDC team in Fort Collins, about 60 miles north of Denver, redirected its expertise to COVID-19. CDC and the Colorado Department of Public Health and Environment (CDPHE) started working together to address some of the mysteries of this new disease.

“Learning about a new, contagious disease requires critical thinking and a collaborative approach,” says Kristen Marshall, a CDC disease detective assigned to CDPHE. “We were able to build a strong, multi-disciplinary team that brought different perspectives to the problem, helped strengthen our study design, and pushed us to think differently.”

Portrait of a CDC disease detective.

Kristen Marshall, a CDC disease detective assigned to CDPHE

CDC and CDPHE staff conducted a telephone survey to assess possible COVID-19 exposures before Colorado’s stay-at-home orders went into effect on March 26, 2020. CDC and CDPHE staff randomly selected 600 patients who had been confirmed to have COVID-19 in nine counties that account for about 80% of Colorado’s population. In 20 days, more than 30 CDC staff made hundreds of calls and got 364 patients or someone representing them, to agree to a 30-minute interview.

“We were eager to hear first-hand accounts from COVID-19 patients and work with a team keen to find solutions for the public,” says Grace Vahey, a CDC disease detective at the Fort Collins office. “As a veterinarian, I am particularly interested in the intersection between human and animal health, or One Health. Since COVID-19 probably originated in animals, a multi-disciplinary approach like One Health is key.”

Lessons learned early in the pandemic still work

Nearly half of participants reported close contact with someone with lab-confirmed COVID-19 or symptoms like fever, cough, or shortness of breath in the 14 days before their symptoms appeared. About one in four participants knew they had been exposed to someone with lab-confirmed COVID-19. Among those, 7 in 10 exposures likely occurred in workplaces or at home. Because workplaces were identified as common locations for potential exposures, it became clear that company officials and managers needed guidance on how to help protect their employees and customers.

Portrait of a CDC disease detective.

Grace Vahey, a CDC disease detective at the Fort Collins office

Among people in the survey who had no known contact with anyone known to have COVID-19, large gatherings and domestic travel were their most commonly reported activities in the two weeks before getting sick. About half the participants did not report contact with either a lab-confirmed COVID-19 patient or someone they knew with fever or respiratory symptoms. CDPHE and CDC staff recognized that hand washing, staying at least 6 feet away from others, and mask wearing could help keep people from getting sick in these settings.

“For me, a couple of things stood out,” Kristen says. “Sixty percent of workplace exposures occurred in healthcare settings, and in March 2020, we were still developing protocols to protect healthcare workers. The study helped highlight the need for these protocols. And with a high percentage of people with no known COVID-19 exposure, we started seeing the importance of wearing masks and social distancing. Over 4 in 10 people with no known exposure had attended a mass gathering.”

The interviews produced a wealth of information. After the initial results were analyzed, CDPHE and CDC staff continued to learn about what made people more likely to be hospitalized for COVID-19, what types of symptoms they experienced, and how symptoms progressed among people in and out of hospitals. That work helped make it easier to recognize COVID-19 and identify people more likely to get severely ill or end up in a hospital.

A year later, health officials continue to encourage prevention lessons learned early in the response—wear a mask, stay 6 feet apart from others, avoid crowds, and wash your hands. What these early investigations revealed is also helping to inform vaccination plans and how to protect those at highest risk for severe COVID-19. These actions have helped pave the road out of this devastating pandemic.