The Maine Center for Disease Control and Prevention has quietly started updating the cumulative number of negative COVID-19 tests on an almost daily basis, though it failed to post new numbers Sunday.

If the agency succeeds in posting the numbers every day, it will make it possible for the public to calculate the percentage of tests that are positive and track the trend going forward.

Maine has been the only state in the country unable to provide the data to track this key metric of the pandemic, a shortcoming national public health experts have said hampers decision makers’ ability to track and respond to the disease quickly.

The Maine CDC has been providing the number of positive COVID-19 cases each day but has released the number of negative tests only on a weekly basis, making it difficult to evaluate whether spikes or dips in cases were a product of the number of tests that had been performed overall. The Press Herald first reported on the problem on April 14. The agency first blamed the difficulty on there being a large number of outside labs to work with but later claimed the information wasn’t needed.

At his May 20 briefing, Maine CDC director Dr. Nirav Shah said the agency would be providing the information “in the coming days,” but the cumulative statewide negative test counts weren’t refreshed until a week later, on May 27, as had been done in the past. The agency refreshed the information on May 30 – three days later – and again on June 2.

In the early afternoon of June 3, the agency refreshed the data on its website for a second day running, making it possible to calculate the previous day’s test count and positivity ratio. Although it made no announcement about the change, it updated the data again June 4, 5 and 6, though it did not do so on Sunday, breaking the data chain before a seven-day rolling trend – a standard metric for tracking the disease in other states – could start being calculated. The data was updated again Monday.

Maine CDC is still providing only the cumulative testing counts, meaning that it is impossible to calculate the trend lines before June 3 or to calculate Sunday’s figures. Maine CDC spokesman Robert Long said via email Monday afternoon that providing daily breakdowns for past data – which would allow broader trends to be seen – was not imminent. “Response to current conditions related to COVID-19 remains our priority,” Long wrote. “When we can redirect resources to providing accurate historic data, we will do so.”

If the agency succeeds in reporting the information daily, it would provide critical information for Maine on understanding the incidence of the disease among people with and without symptoms, said Dr. Jennifer Horney, founding director of the epidemiology program at the University of Delaware’s College of Health Sciences.

“Rapid access to data related to the number of both positive and negative test results will paint a clearer picture of areas or regions of concern by assessing areas where the rates of positive tests are not declining or are declining more slowly,” Horney said via email.

On the agency’s website, the tests are broken out between so-called PCR tests (which determines someone has the disease now) and antibody tests (which indicates whether someone had it in the past) and also between results reported to the Maine CDC electronically and those that are not. A note at the bottom of the online data tables says: “Labs reporting manually report only the positve [sic] results and are therefore excluded for purposes of calculating the percent positivity rate.”

It is not clear why these labs cannot also provide negative data manually, but based on the data presented on the website, it affects only a small percentage of the overall tests. CDC spokesman Long said the agency’s policy is to “exclude manually reported negative results until their laboratory staff can validate them” and said this “aligns with best practices for public health laboratories.”

The agency’s website also shows the positivity rate for all electronically reported tests since the pandemic began, which for PCR tests stood at 5 percent on June 2 and 4.8 percent on June 6.

Maine has lagged the other New England states in data gathering since the start of the pandemic, though it has slowly improved over time. The state CDC was unable to say how many COVID-19 patients were hospitalized on a given day – a key metric of the burden on hospitals – until April 10, three days after the Press Herald published a story on the shortcoming; and was unable to provide an accurate count of intensive care unit beds and ventilators until the week of April 5, more than three weeks after the first confirmed case in the state.

On June 3, the agency posted cumulative case counts on a zip code level for 14 of Maine’s 16 counties, revealing where the disease has been concentrated and where it has not. It had been the only state in New England reporting case counts only at the county level.

Maine has continued moving forward with a phased reopening plan that started May 1, with the reopening of hair salons and doctor’s offices, and continued with the resumption of retail and some dining room operations between May 11 and June 1, depending on the county.