Nearly three months since the first coronavirus case was detected here, Maine remains the only state in the country that is unable to provide a basic daily pandemic tracking metric: the number of tests performed and the percentage of those that tested positive.

The Maine Center for Disease Control and Prevention is also unwilling or unable to provide these metrics for each county, even on a weekly basis, as Gov. Janet Mills’s phased reopening plan proceeds on a county-by-county basis. The data, the agency says, is not available, raising questions about how the administration is able to make informed reopening decisions.

Meanwhile, the state CDC finally began releasing infection data by zip code Wednesday evening, becoming the last state in New England to let residents know how many people in each town or zip code has been infected with COVID-19.

The Maine CDC provides positive test numbers on a statewide and county-level basis every day, but has long said it cannot also provide the number of negative tests because of the difficulty of compiling them from various outside labs and reporting sources. Without the negative test numbers, it is difficult to evaluate what the number of positives really means, as an increase or decrease can simply be a product of having done more or fewer tests.

Public health experts have for weeks told the Press Herald that this is a serious shortcoming, and they reiterated that this week.

“By not reporting out daily the positive and negative tests, the state will not have the ability to regularly assess whether it is testing enough for the level of infections that are occurring within its borders,” Dr. Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, said via email. “It’s hard to gauge trends in data that is only reported every seven days, and by waiting to report new data the state is missing opportunities to check and see if a course correction is necessary.”

Jeremy Youde, who studies the intersection of government and public health at the University of Minnesota Duluth, said having this information is particularly important if you are in the midst of a phased reopening partly based on the trends in new infections. “If you only have once-a-week data, you lose the granularity that helps policymakers to assess whether they can or should move through those different phases,” he said.

“I know that your part of the country and mine are both really dependent on tourism during the summer months, so there’s a lot of additional pressure to get things back to something close to normal, but it’s hard to make those changes without having detailed data,” Youde added.

On May 20, Maine CDC Director Dr. Nirav Shah said the data would be coming “in the near future.” Responding to follow-up questions from the Press Herald, CDC spokesman Robert Long said via email that they planned to have it up by May 28. Asked about it again, Long said Tuesday via email that “we expect to soon be able to report daily statewide test totals.”

It remains unclear why Maine CDC has been unable to release this essential metric that every other state in the country calculates each day. The other five New England states have been providing full daily data on their websites since March, with some breaking down the totals by laboratory. Asked why the Maine CDC couldn’t provide the metric at least for tests it performed itself at its own lab, Long responded that the same issues applied.

The Press Herald requested an interview with Shah to understand in greater specificity what the special challenge is for Maine, but he was not available. Asked to elaborate on this, Long suggested Maine has higher standards than other states.

“There have been reported problems with testing numbers data in multiple other states,” he wrote. “Early during the pandemic, the contractor that Massachusetts uses to present its case data had to make a significant revision to the data it reported,” Long wrote. “As Dr. Shah has stated often during media briefings, Maine CDC’s focus is on presenting accurate information that is of value to the public.”

Nuzzo, the Johns Hopkins epidemiologist, said she really didn’t understand the agency’s explanation. “Sure, states have had data troubles. But they are beside the point,” she said via email. “Maine is the only state not reporting positivity on a daily basis.

Youde agreed. “The Maine CDC isn’t wrong about the problems other states have been having or the fact that we’ve seen some states have to revise their data,” he said. “That said, it’s not clear why poor practice by other states would prevent Maine from setting a model for how to do this correctly.”

On Wednesday evening, the Maine CDC posted ZIP-code level data on cumulative case counts to date. Since April 27, Maine had been alone in New England in presenting the information only by county.

The data breaks out the number of total cases in every zip code in 14 of Maine’s 16 counties, except for those where there are either fewer than 50 residents in the ZIP code or five or fewer cases. The agency said on its website that it had suppressed all data for Piscataquis and Washington counties and for the sparsely populated ZIP codes to ensure patients’ privacy. The agency’s data map marks other counties that have five or fewer cases, but does not provide the exact case count to further ensure patient privacy.

Long said Tuesday that the agency had not taken this step earlier because “Massachusetts and New Hampshire began posting town-level data when their statewide case counts were at or above levels that Maine has now reached.” He added that “Maine’s statewide cumulative case count has now reached a level at which more granular data presentation poses a reduced risk for unintentional release of personally identifying information.”

On May 22, Maine ceased to be the state with the lowest per capita COVID-19 prevalence, passing Vermont. Maine’s worst affected county, Cumberland, had a higher prevalence Wednesday – 410 cumulative cases per 100,00 people – than Vermont’s hardest-hit county, Chittenden, where Burlington is located (278 cases). Cumberland County is also not markedly lower than New Hampshire’s most affected counties, Hillsborough (609) and Rockingham (427), where Manchester and Portsmouth are located, according to data complied by the Johns Hopkins University School of Medicine. Androscoggin County (at 292 cases per 100,000) now has a higher rate than New Hampshire’s Merrimack or Stafford counties, home to Concord and Dover.

Maine has lagged the other New England states in data gathering since the start of the pandemic. 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.

While Massachusetts has for months provided detailed information on the number of people hospitalized with COVID-19 at every hospital in the state, Maine does not. The Press Herald has gathered the data from the hospitals each week, which revealed the initial flattening of the outbreak across the state in April and a more recent resurgence at southern Maine’s hospitals.

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.