Nevada this week became one of the last states to publicly report rapid antigen tests as part of its coronavirus tallies — a move that experts said could provide a fuller picture of the pandemic but also upend metrics used to gauge how the virus is spreading.
The change leaves Maryland as the lone U.S. state that doesn't incorporate rapid tests in its online dashboard or include them in virus statistics, as the U.S. Centers for Disease Control recommends, according to an Associated Press review of dashboards and policies for all 50 states.
Nevada has been among the states hit hardest by the pandemic. The state's hospitals have been pushed to near capacity, its unemployment has broken national records, and 435,000 people have tested positive for COVID-19. Omitting rapid tests from its tally limited the public's understanding of the pandemic’s spread in the state, Nevada health officials acknowledge.
Officials told the AP in September 2020 that they were working to publicly report antigen and molecular tests separately on their dashboard. On Monday, they said delays stemmed from the overburdened state public health system having to juggle competing priorities with limited resources.
The rapid antigen tests, which detect the presence of viral proteins rather than the coronavirus itself, return results in minutes, unlike traditional molecular tests sent to labs, which can take days to process but are shown to be more accurate. Their quick turnaround times have led to their widespread use in prisons, schools and nursing homes.
President Joe Biden praised rapid tests last month, but supply shortages and the varied ways that states report them reflect the continued absence of a national testing strategy. Some states report antigen tests separately, with positive results as “probable cases” while others combine them with molecular tests for an overall tally.
On Monday, Nevada added more than 600,000 new tests to the online dashboard that shows coronavirus case and death counts, vaccination rates and positivity rates. The infusion spiked the number of COVID-19 cases reported statewide by 9,700 and decreased the positivity rate by one-sixth, from 10.1% to 8.8%.
University of Nevada, Las Vegas epidemiologist Brian Labus said scientists never assumed testing data provided a complete picture of COVID-19's trajectory and instead used it to pinpoint trends. It's easier to gauge when COVID-19 surges and drops if cases are counted the same way, he said, especially regarding statistics used to determine the need for prevention measures like mask mandates.
One criteria that triggers county mask mandates for indoor public spaces is an 8% positivity rate, which the CDC defines as “substantial” transmission.
“Changing now will probably cause some disruption to that system," Labus said.
While other states have embraced antigen tests, which are also called point-of-care tests, Nevada has been comparatively skeptical. A year ago, federal officials chided the state when it decided to halt their use due to accuracy concerns.
Nevada, which was the only state to stop using the tests, subsequently reversed the ban.
Nevada began reporting rapid tests from prisons toward its cumulative case count in December and approved them for use in school reopening plans and in the protocols for large events like last month’s 60,000-attendee Life is Beautiful Music Festival. Those approvals, however, didn’t compel the state to include most of the tests toward calculating infection rates.
The Nevada Department of Health and Human Services made the decision to direct resources and staffing toward distributing vaccines and contact tracing and, at the height of the pandemic, didn’t have capacity to investigate every positive result from a rapid antigen test, said state epidemiologist Melissa Peek-Bullock.
Although it wasn't consistent to report rapid tests only from state prisons, she said not counting them would have denied inmates, guards and their families vital information about the pandemic’s reach in prisons.
With a drop in new cases, Nevada now has the capacity to investigate positive antigen tests as probable coronavirus cases, Peek-Bullock said.
“The reporting of the antigen tests really give us a better picture of what’s happening disease burden-wise across our state. With the schools using it, with correctional facilities doing mass use of antigen testing and a lot of employer-based testing — we’ve just reached a point in the pandemic where we absolutely have to take into account these positive results,” she said.
An average of 17,700 antigen tests a week were reported to Nevada health officials in August and the first three weeks of September, state data show.
Nevada wasn't the only state struggling to process hundreds of thousands of different kinds of tests, said Janet Hamilton, the executive director of the Council of State and Territorial Epidemiologists. Test results aren’t transmitted electronically from providers to health departments, forcing them to process large volumes of paper. Those kinds of time-consuming undertakings stem from a long-term lack of funding for public health systems and infrastructure nationwide, she said.
“We should have electronic case reporting, but public health, until very recently, was never funded to support it. Providers were never incentivized to participate in the process or ensure that their electronic medical record systems were sending data to public health,” Hamilton said.
The lack of infrastructure has been particularly severe in Nevada, where officials began the pandemic relaying test information to the federal government via fax machine.
Maryland continues to only report molecular tests. State health officials did not respond to requests for comment.
Though 49 states now publicly report the rapid test positives as probable cases, epidemiologists worry that incorporating them doesn't fully provide a complete picture.
At-home tests, including those that consumers can purchase on Amazon or at their local drug stores, do not require any reporting to health departments. Nevada recommends people whose at-home antigen tests return positive results to confirm it with molecular tests, which gives the state more complete data and allows them to contact trace.
“As epidemiologists, this is something that we are very conscientious of. The data that you have tells the story in either complete or incomplete ways,” Hamilton said. “We are telling an incomplete story around the total number of people that actually have COVID-19.”
