Adults who tested positive for the coronavirus were about twice as likely to have dined at a restaurant within a two-week period prior to becoming sick, according to a new study from Centers For Disease Control and Prevention.

The study included 314 adults who had showed symptoms of COVID-19 and had sought testing at one 11 facilities across 10 states in July. Of the participants, 154 tested positive for COVID-19, while 160 tested negative and served as a control group.

Participants were asked various questions, including how often they had worn face coverings in public and where they had gone two weeks prior to having shown symptoms.

Seventy-one percent of people who tested positive said they had always worn face coverings in public, as opposed to 74% of the control group.

The study found that both positive and negative cases reported going to gyms, hair salons, shops and in-home group gatherings at about the same rate. But the positive cases were about twice as likely to report dining out at restaurants within the 14-day period before feeling sick.

"Masks cannot be effectively worn while eating and drinking, whereas shopping and numerous other indoor activities do not preclude mask use," researchers wrote.

The study also points out that many reported cases tied to restaurants have been linked to air circulation.

"Direction, ventilation, and intensity of airflow might affect virus transmission, even if social distancing measures and mask use are implemented according to current guidance," the CDC notes.

Those who tested positive were more likely to have been in close contact with someone known to have COVID-19 – 42% compared to 14% of the control group. Of those close contacts, 51% were family members.

Though the study has limitations — including its size and the fact that participants weren't asked to distinguish between indoor or outdoor dining — it echoes concerns over safety in bars and restaurants during the pandemic. Many states have imposed restrictions on reopened restaurants.

CDC researchers recommend continued assessments of the risks of various activities especially as more schools, communities and workplaces reopen.

"Implementing safe practices to reduce exposures to SARS-CoV-2 during on-site eating and drinking should be considered to protect customers, employees, and communities and slow the spread of COVID-19," the CDC researchers wrote.

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