COVID-19 infections at Pacific Northwest National Laboratory (PNNL) early in the pandemic were caused by a wide variety of viral sequences, according to a new analysis by Laboratory researchers.
In a paper published in the journal PLOS One, scientists Kristin Omberg, Owen Leiser, and colleagues analyzed the genetic makeup of the viral sequences that infected 36 staff members at the PNNL-Richland campus between January and October 2021. They entered the sequences into global databases containing more than 8 million genetic sequences of SARS-CoV-2, the virus that causes the disease, from people who had been infected.
The team found that the sequences infecting employees were unexpectedly diverse. The closest genetic relatives to the viral sequences that infected employees were found not in others at PNNL but instead in patients in Texas, Oregon, Virginia, California and other states, as well as Washington State.
“The fact that there was so little relation between the samples in our study, all drawn from people working at one location, really was a surprise,” said Omberg, who led the study. “We’re not exactly sure why that is.”
One possibility is that travelers from one region of the country to another brought the virus to new regions. Also, even with millions of sequences available, more would enable researchers to track viral lineages even more closely.
The study included viral samples from employees who had come to campus for testing, who had also given consent for their samples to be used in research, and who then tested positive for COVID-19. While infections beginning in late summer 2021 were largely of the delta variant, earlier infections were from previous lineages, closer to the original COVID-19-causing virus.
At the time, the infection rate among staff at PNNL was about one-third the rate of the general population in the Richland area. Of the 36 infections studied, only one was considered a possible workplace transmission.
PNNL was the only DOE lab to conduct a research study of COVID-19 among its own population, quickly pulling together scientists, human research experts, and others to conduct the study in the thick of the pandemic.
“We’re very appreciative of the people who were willing to contribute their samples for research,” said Omberg. “Their actions helped us understand this disease more thoroughly, to better prepare for the future.”
More than two dozen PNNL scientists contributed to the study, which was funded by DOE’s National Virtual Biotechnology Laboratory and the Coronavirus CARES Act.
Omberg’s team played an important role in the nation’s response to the virus, helping the U.S. Food and Drug Administration evaluate the accuracy of tests used in laboratories across the country. The team identified one widely used test whose results were unreliable and has documented how tests respond to different strains of the virus.