Where is the Minnesota Serology Survey? It would tell us who has had coronavirus. – Twin Cities

ROCHESTER, Minn. — It seems like the first question a state health department would want to get answered: Just how many of us have had the coronavirus, anyway?

Called a seroprevalence survey, it measures how many Minnesotans have gotten the virus and developed antibodies.

Think about it like this: here at the start of July, we know a lot more about COVID-19, than we did back in February. We know about its strange mix of symptoms: fever, low oxygen, dry cough and losing your ability to taste.

We know how COVID-19 spreads fastest: extended, loud conversation and singing at bars, parties, choir practices, funerals and other sustained indoor contact.

We know what prevents the spread of COVID-19 best (masks, handwashing and distancing).

We know COVID-19 sometimes has no symptoms, that the asymptomatic can shed the most virus of anyone, and who it hits the hardest: the elderly, those with underlying health problems, and possibly the healthy who have contracted high doses of the virus.

Rural workers have learned that living in wide-open spaces won’t protect you if you work in close quarters, and urban dwellers have learned they can put on a mask, protest in the open air and come away fine.

But we haven’t learned how many of us have already had it.

The answer would tell us a lot. Moreover, it’s not a complicated question to answer, we have the tools to do it, and we have had them for several months.

In theory, a basic COVID-19 seroprevalence study should take about a week, two at most. You recruit a representative sample of 500-1,000 statewide residents. You send phlebotomy technicians out to their homes. You draw vials of blood, pay them for their time, and test it all for the virus.

But you wouldn’t know this by remarks on Monday, June 29, as Gov. Tim Walz was joined by representatives of Mayo Clinic and the University of Minnesota labs to celebrate the state’s having reached its target capacity to process 20,000 diagnostics tests a day.

Asked about serology testing, state Commissioner of Health Jan Malcolm deferred to the Mayo and the University of Minnesota, adding that “they have been doing that serology testing under this partnership.”

First up was Dr. Timothy Schacker, Vice Dean for research at the University of Minnesota Medical School.

“At this point in time, a lot of the antibody testing that’s been done in Minnesota has been done on select populations,” said Schacker. “We don’t have a lot of data to say what the seroprevalence is across the entire state.”

“I can tell that you in our serology testing we have focused on health care workers and we have focused on just general seroprevalence in the Twin Cities,” Schacker added, “and it’s come out between 4-5 percent. And that’s about what you’d expect given the number of positive tests in the state.”

Added Dr. William Morice of the Mayo Clinic: “I do think it’s (still) the very early days with serological testing to really draw conclusions. It will be part of the discussion as we go forward, how will serological testing be used to help manage the pandemic, now that we are in the management phase.”

THE CALIFORNIA EXAMPLES

In May, a group of researchers from Stanford conducted serosurveys in northern and southern California, and found the virus was far more widespread than believed, suggesting it lethality was overstated. The former was subjected to critcism for analytical reasons, but few have offered to produce counter-surveys.

For the next 12 months, an ongoing federal Centers for Disease Control and Prevention seroprevalence study is making monthly checks of donor blood for COVID-19 antibodies, sampling from 1,000 donors in each of 25 metro areas. That investigation will be broadened to 25,000 donors at the 18-month mark. Minneapolis is one of these cities.

MDH RUNNING, PREPARING 5 SEROSURVEYS

Minnesota Department of Health spokesman Doug Schultz says that five serology studies utilizing finger-prick blood testing are now being funded with $2 million from the state’s COVID response fund and from the CDC. Schultz said the state prioritized blood-prick technology in order to broaden their sample size, but that waiting for this technology to come online had slowed the start time.

Schultz said the Health Department received serosurvey proposals from University of Minnesota in late April, however, and began planning the studies in early May while waiting for state COVID relief funds to be approved.

With the state money now in hand, these have included a bloodbank study, and a so-called CASPER field methodology study (for Community Assessment of Public Health Emergency Response). Both are to be conducted by Health Department personnel who will be reassigned from other positions.

Schultz said the bloodbank survey is the simplest, because it uses leftover blood from donors. The samples are de-identified — the state will receive some demographics with them, but they are not linked to cases. “The bloodbank is already pulling specimens,” Schultz said. “We will look at 1,000 samples now, 1,000 in fall and 600 of these from metro, with 400 from the Northland. We will repeat that in fall.”