Maryland releases more contact tracing data showing ‘high-risk locations’ for coronavirus

The Maryland Department of Health began providing more data on its contact tracing website, including whether people attended large social gatherings, visited high-risk locations or went to work.

State health officials released more contact tracing data late Wednesday that shows where some COVID-19 patients might have been exposed to the infectious virus.

The new information, previously requested by The Baltimore Sun but not released before, shows the number of people case investigators reached in a single week, breaking down the information by those interviewed and those who provided additional contacts to call.


The data also shows whether people attended large social gatherings, visited “high-risk locations” or went to work within 14 days of getting their result or feeling symptomatic.

Of the people interviewed from July 10 to Aug. 19, 26% reported having gone to work outside the home and 13% reported attending a social gathering of more than 10 people.


Of the 41% who reported visiting a high-risk location, most ― 9,863 — said they worked outside the home, followed by going shopping indoors (6,658), eating at an indoor restaurant (3,745), eating at an outdoor restaurant (3,345), participating in outdoor recreation (2,739), conducting personal services (1,969), exercising at a gym (1,289), attending a religious worship service (907), going to an indoor recreation event (674), and finally, going to a casino (369). Respondents could select more than one response.

The data also shows the work environments in which infected people may have contracted the illness.

More individuals worked in health care — 2,875 — than any other area. Health care was followed by “non-public-facing workers” such as those who work in warehouses, offices or auto body shops at 2,293.

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Next came those in “public-facing” jobs such as administrative and front desk staff at offices, home repair workers, landscapers and security guards at 1,844, followed by those who work in food service (1,407), construction and manufacturing (1,005), retail establishments that do not sell food or medicine (642), transportation (521), groceries and pharmacies (510), law enforcement and first response services (399), hotels (372), child care and education (317), and barber shops, salons and spas (129).

Maryland Gov. Larry Hogan has encouraged people repeatedly to work from home if they are able to do so. But the data underscores how many people in the state likely do not have that ability, and how many of them might suffer as a result.

Of the 5,944 people who acknowledged attending a social gathering of more than 10 people, more than a third — 2,217 — said they went to a family gathering, while 1,188 reported going to a house party and 1,051 said they attended a large outdoor event. At the lower end of the scale were religious services (638), funerals (468), weddings (274), and professional or youth sporting events (250).

Since June, contact tracers have successfully contacted more than 44,000 people who have tested positive for COVID-19, according to the website. Of those, 27,675 provided at least one additional contact for investigators to call.

As of Wednesday, the state has reported 121,297 cases of confirmed coronavirus infections. Of those, 3,756 have died from COVID-19, the illness caused by the virus.


Successful contact tracing depends on a caller’s ability to connect with people by phone and to do so within a tight enough time frame that the virus gets contained within a transmission chain. With test results delayed across the country due to inventory shortages and skyrocketing demand, some have questioned whether the public health tool makes a difference, and whether its launch in June happened quickly enough to prevent mass community transmission.

Contact tracing also depends on the cooperation of the individual: According to state data, about one in four people asked did not provide answers to questions about their workplace in the two weeks leading up to their positive test result or symptom onset.