During a Senate hearing on Capitol Hill Tuesday, Centers for Disease Control and Prevention director Dr. Rochelle Walensky defended her agency’s claim that less than 10 percent of COVID-19 cases are transmitted outdoors amid criticism from scientists who believe the figure is misleading.
Senator Susan Collins pressed Walensky on the CDC’s use of the 10 percent stat, citing Tuesday New York Times reporting which suggested the benchmark for outdoor transmission is actually much lower than 10 percent.
“There is not a single documented Covid infection anywhere in the world from casual outdoor interactions, such as walking past someone on a street or eating at a nearby table,” the Times David Leonhardt reported.
Confronted with Leonhardt’s reporting, Walensky fell back on a study which used the figure, but did not defend the study’s methodology.
“The top line result of all studies included in the systematic review said less than 10% of cases are transmitted outdoors,” Walensky commented in response to questioning from Collins. “It was a published study that synthesized study from many places.”
Leonhardt explained that CDC officials chose a high benchmark of 10 percent that had little basis in scientific reality. Dr. Muge Cevik, a virologist at the University of St. Andrews, said the benchmark “seems to be a huge exaggeration.” His report cited multiple epidemiologists who believe the share of outdoor transmission is closer to one percent and could be below 0.1 percent. When rare outdoor spread does occur, it is in crowded venues and congested spaces, according to the report.
In addition to the flawed CDC guidance on outdoor coronavirus transmission, Collins said the CDC’s reasoning for summer camp and school re-opening delays are also chipping away at the organization’s credibility and reputation.
Walensky addressed the accusation that the American Federation of Teachers, a powerful teachers’ union, unfairly lobbied the CDC to include new language in February guidance that would prolong remote teaching. The director said the addition was meant to fix an “oversight” and incorporate the concerns of immunocompromised teachers.
“The conflicting, confusing guidance from your agency has undermined public confidence and contradicts the scientific guidance of many experts,” the senator remarked. “I used to have the utmost respect for the guidance from the CDC. I always considered the CDC to be the gold standard. I don’t anymore.”
Collins repeated that the American people are losing trust in the agency’s public health recommendations.
“Here we have unnecessary barriers to reopening schools, re-exaggerating the risk of outdoor transmission, and unworkable restrictions on summer camps,” Collins said. “Why does this matter? It matters because it undermines public confidence in your recommendations. In the recommendations that do make sense.”