Minnesota is finalizing plans for a new lab that would process COVID-19 tests based on saliva samples, an innovative approach to diagnosing patients that would dramatically expand the state’s capacity to test for the virus.
State officials said Tuesday that they are in the midst of completing a $14.6 million contract for a New Jersey research group and another contractor in New York to provide tests and open the facility planned for Oakdale, likely by early October.
Testing alone can’t stop the spread of a virus, but the capacity will help health officials find outbreaks earlier and better protect schools as teachers and staff return this fall, said Jan Malcolm, the state health commissioner.
The deal gets Minnesota closer to the goal of suppressing COVID-19, but Malcolm cautioned the target likely will remain elusive.
“The planned lab will give us the ability to more than double the state’s current test processing capacity,” she said during a call with reporters. “We know it’s important to continue growing and diversifying that capacity to test as we enter the next phases of the pandemic.
“We can’t emphasize enough the central importance of testing to help shine a light on where we are, but it needs to be part of this larger containment strategy, as well.”
The new lab would be capable of processing up to 30,000 samples per day when running all three shifts. The state says Minnesota’s current testing capacity ranges from 20,000 to 22,000 tests per day.
The current supply has grown from much smaller numbers this spring due in large part to the state’s $36 million “moon shot” program for testing capacity at the Mayo Clinic, the University of Minnesota and HealthPartners.
Earlier this month, the Minnesota Department of Health announced a program to make saliva testing available to public and private school teachers and staff as a way to screen for the novel coronavirus that could be easier on patients.
The “gold standard” method of obtaining samples relies on nasopharyngeal swabs that reach deep inside the nasal cavity for a specimen. The method can be uncomfortable for patients, to the point that an editor at the New England Journal of Medicine described it as a “brain biopsy.”
“The saliva test requires much less personal protective equipment … because it is self-collected under the supervision, but not the hands-on administration, of a health professional,” Malcolm said.
On Tuesday, the Minnesota Department of Health reported eight more people have died of COVID-19 in Minnesota, including four residents of long-term care facilities.
The state saw a net increase of 409 new infections on a volume of about 8,858 completed tests. Over the past week, the state has averaged about 664 new cases per day on a daily volume of about 17,419 tests.
The share of positive tests has ranged between 4% and 5% in recent weeks, which is lower than the level state leaders have suggested might call for more restrictions to slow the spread. On Monday, the Health Department said 243 out of 13,418 people tested in the wake of the Minneapolis police killing of George Floyd tested positive for SARS-CoV-2, for a lower-than-expected positivity rate of 1.8%
To “mitigate” the virus, or keep current outbreaks from growing, Minnesota needs slightly more than 17,000 tests a day, according to estimates from the Harvard School of Public Health. Another requirement for mitigation is keeping the share of positive tests at or under 10%.
Suppressing the virus is a harder target. That would require more than 63,500 tests a day, according to Harvard estimates, and would help reduce new infections to a level for safely reopening public life.
“Many U.S. states are not now doing enough testing,” said Stephen Kissler, a research fellow at Harvard. “I think this would go a long way toward addressing that gap in Minnesota.”
While saliva tests offer patients a more convenient way to provide a sample, “there are published data showing that detection of SARS-CoV-2 in saliva is not as sensitive compared to a nasopharyngeal swab,” said Matthew Binnicker, director of clinical virology at Mayo Clinic, in an e-mail. “So, you sacrifice sensitivity for convenience of collection.”
But Kris Ehresmann, the director of infectious disease epidemiology at the Minnesota Department of Health, argued that the degree of trade-off is “pretty small.”
One study compared tests on saliva samples with those taken with nasopharyngeal swabs and found the results were the same 94 to 99% of the time, Ehresmann said. That particular study didn’t focus on the tests from the state’s new partnership, which were developed by a research group at Rutgers University called Infinite Biologics.
“It does take a fair amount of saliva,” Ehresmann said of the test, which she took as part of a pilot group. “With any of these tests, I think it’s important to consider that nothing is easy, but this is a good solid test and has good results.”
Testing experts say the state should use a variety of methods and figure out which are best for different settings, Malcolm said. Nasopharyngeal swabs probably won’t be replaced by saliva sampling in “clinically important uses,” she said, but the new tests will play an important role, nonetheless.
“We believe with increased demand for testing by a whole bunch of different sources — schools, employers, being able to do more public health surveillance testing — we’re going to need all the capacity we have plus some,” Malcolm said. “It will be important to apply some judgment as to which tests are best for which types of situations.”
Throughout the pandemic, Minnesota and other states have struggled at times to provide enough tests because of shortages of swabs as well as chemicals needed to run tests, Malcolm said. So, having options is key.
Infinite Biologics and partners earned the first emergency use authorization from federal regulators for a saliva-based method of testing for the genetic material of the pandemic virus. The state’s partnership also involves a New York-based company called Vault Health, which provides logistics and telehealth services to carry out the test.
The state is planning to offer saliva tests at 10 semi-permanent sites around Minnesota as well as through mobile and at-home testing. The new lab would employ up to 250 people.
On Tuesday, the Health Department said 312 patients were hospitalized with COVID-19 including 137 patients in intensive care. The numbers fit with a recent trend of steady counts for hospitalized patients in Minnesota.
Statewide, 1,779 people have died from the virus, including 1,315 deaths in long-term care or assisted-living residents.
COVID-19 is a viral respiratory illness. People ages 65 and older, residents of long-term care facilities and those with certain underlying medical conditions are at greatest risk of serious illness. Most patients don’t need to be hospitalized. The illness usually causes mild or moderate sickness, and many who are infected don’t show symptoms.