Courtesy Image An illustration of the coronavirus provided by the U.S. Centers for Disease Control and Prevention.

ALPENA — The number of Northeast Michiganders actively infected with the coronavirus inched upward again this week as the U.S. Centers for Disease Control and Prevention said COVID-19 vaccines have been less effective against the omicron variant of the disease but still greatly reduce the chances of hospitalization or death.

As of Thursday, at least 772 Northeast Michiganders were actively infected with COVID-19, while about 59% of Northeast Michiganders 5 and older had been fully vaccinated against the disease.

This week’s active infections — a News estimate based on cumulative infections minus deaths and those who fit the CDC’s definition of recovered — is up from 679 active infections last week.

The true number of active infections is likely higher, as The News’ estimate is based on numbers reported through District Health Departments No. 2 and No. 4 and doesn’t account for any positive results from home testing not reported to the health departments. It also doesn’t account for asymptomatic people who never take a test but could still spread the disease.

Meanwhile, among those 5 and older, the state says 57% of Alpena County residents, 63% of Presque Isle County residents, 57% of Montmorency County residents, and 59% of Alcona County residents have been fully vaccinated against the coronavirus.

The state adjusted downward the share of vaccinated residents in Presque Isle and Montmorency counties. It wasn’t immediately clear why they’d done so, but the state has frequently adjusted numbers as officials review raw data reported by vaccination clinics.

The chart below shows the number of Northeast Michiganders actively infected with COVID-19, a News estimate based on cumulative infections minus recoveries and deaths. The story continues below the graphic.

Meanwhile, new data out this week from the CDC shows vaccines have been less effective against the omicron variant of the coronavirus, though unvaccinated people were still seven times as likely as vaccinated people to end up hospitalized with COVID-19. The unvaccinated were 15 times as likely to end up hospitalized during the wave of the delta variant of the virus.

A chart released Thursday by MyMichigan Health, the Midland-based owner of the Alpena hospital, showed 17 unvaccinated and 16 vaccinated COVID-19 patients across its hospital system. Two COVID-19 patients were in intensive care units, both of them vaccinated.

That’s a far closer split than the hospital system reported on Feb. 10. Then, the hospital system had 45 unvaccinated and 17 vaccinated COVID-19 patients, with seven unvaccinated and four vaccinated patients in the ICU with coronavirus infection.

In the past week, public health officials have reported 94 newly infected or probably infected Northeast Michiganders and the death of one Northeast Michigander who had been infected with COVID-19.

The chart below shows the number of Northeast Michiganders 5 and older fully vaccinated against COVID-19. The story continues below the graphic.

Since February 2021, Northeast Michigan health officials have reported confirmed and probable infections as one number. A person counts as a probable infection if they’d been exposed to a confirmed infected person and are showing symptoms but hadn’t been tested, themselves — such as family members of infected people.

The chart below shows the number of COVID-19 patients admitted at MidMichigan Medical Center-Alpena. The story continues below the graphic.

As of Monday, six COVID-19 patients were hospitalized at MyMichigan Medical Center Alpena, none of them in intensive care. The hospital was 82% full.

Since the pandemic’s start in mid-March 2020, public health officials have reported 10,942 Northeast Michiganders infected or probably infected, and 269 related deaths.