KEY POINTS

  • CDC stated activities where mask usage were hard to be followed might increase COVID-19 risk
  • Researchers said community exposure of participants with and without COVID-19 cases were similar
  • The team said exposure in restaurants was linked to ventilation, which affects how the virus is transmitted 

People who tested positive for COVID-19 were 2.8 times more likely to have frequented restaurants two weeks prior to their diagnosis compared to those who did not have the infection, a study by the Centers for Disease Control and Prevention (CDC) revealed.

The study, published in CDC's Morbidity and Mortality Weekly Report on Thursday uncovered the difference between the behavior of uninfected individuals and those who tested positive but had no known contact with a COVID-19 patient. It said those who reported going to bars or cafes were 3.9 times more likely to contract the disease, but this result was restricted to people who were not in close contact with COVID-19 patients. 

The report stated exposures and activities where social distancing and mask usage were hard to be followed -- such as establishments where on-site drinking and eating are allowed -- might increase the risk of contracting COVID-19.

The CDC team investigated adults aged 18 and above who tested for SARS-CoV-2 from July 1 to 29. After various screening processes, the final analytical sample included 314 participants of which 160 were negative and 154 positive. 

Personnel from the CDC interviewed the participants and the data was then processed by REDCap software. It was found 42% of patients had close contact with one or more family members compared to the 14% who tested negative.

Researchers ascertained that community exposure and mask-wearing habits of participants with and without COVID-19 cases were similar. However, people who tested positive revealed they were more likely to have visited a restaurant or a bar, where on-site dining was allowed, within 14 days before the onset of the illness. About one-half of all the participants revealed going shopping or visiting others in their homes. 

Restaurants in Canada have been among the businesses hardest hit by the coronavirus shutdown Restaurants in Canada have been among the businesses hardest hit by the coronavirus shutdown Photo: AFP / Eric THOMAS

The team stated exposure in restaurants was previously linked to ventilation and the airflow, which affects how the virus is transmitted. What makes a huge difference between shopping and dining is that with the former, masks are still worn, while at a restaurant, it needs to be taken off to eat. 

According to the CDC, the study has limitations. For example, the participants were from health care facilities and might not be representative of the American population. Another limitation is that they were aware of their COVID-19 results, which may have possibly influenced their responses. Lastly, imperfect sensitivity of the PCR-based testing might have led to misclassification.

The CDC recommends wearing masks in public, as one of the safety precautions against coronavirus infection. The agency also published guidelines for bars and restaurants Sept. 6. It advised the establishments to promote strategies that encourage behaviors, which would help reduce COVID-19 spread. It underscored how employees should stay home when needed, observe frequent handwashing and the use cloth face coverings.