Anthony Fauci, the infectious-disease doctor who served as a key COVID-19 advisor in the United States has acknowledged that there was little science behind the six-foot social distancing rule.

“It just sort of happened, that six feet is going to be the distance,” Fauci testified to Congress in a January closed-door hearing, according to a transcribed interview released on Friday.

Fauci said that the six-feet rule was not based on scientific data.

Francis S. Collins, former director of the National Institute of Health, also privately testified to Congress in January that he was not aware of evidence behind the social distancing recommendation, according to a transcript released in May.

While it is not clear why the US Center for Disease Control and Prevention settled on the six foot distance as the agency had repeatedly declined to specify the authors of the guidelines.

The United States’ distancing measure was particularly stricter, as other countries adopted shorter distances. The World Health Organization (WHO) set a distance almost three feet as effective to deter infections.

The six-feet distancing rule had the biggest impact on children as many schools were unable to accommodate six feet space between students’ desks and had to rely on online education for over a year.