Medical experts are wrestling with questions about who should get the COVID-19 vaccine shots as well as the treatment's long-term effects as Minnesota health care centers prepare to receive vaccine vials next week.
Children, pregnant women and mothers who breastfeed will not be vaccinated in the initial waves because safety and efficacy studies are not yet complete.
In Minnesota, everyone who gets the two-dose vaccine will be given a card that will prove that they are inoculated, but researchers still don't know how long immunity protection will last.
Clinical trials on the two vaccines that are expected to get federal emergency approval this month have demonstrated safety and 95% effectiveness in the short-term.
But some of the 40,000 participants in the trial for the Pfizer version of the vaccine, for example, might have gotten an infection that was not apparent.
"The end point was symptomatic disease," said Dr. Melanie Swift, an occupational medicine physician at the Mayo Clinic in Rochester. "They did not take these 40,000 people and test them to see if they had asymptomatic disease."
That could mean that even though some people have gotten the shot, they still might be asymptomatic spreaders of the new coronavirus.
Many questions will eventually be answered as both vaccines, as well as others, are slated for follow-up studies for another two years.
Both vaccines were developed at an unprecedented speed, but doctors and health officials say that the most critical evaluation standards were not compromised.
"Other vaccine studies, when they go through the phase three trials … generally have about 5,000 to 6,000 people," said Dr. Abinash Virk, an infectious disease expert at the Mayo Clinic. By comparison, enrollment in both the Pfizer and Moderna vaccines was 74,000.
"From a scientific perspective we know that we can rely on the data that we are getting through these studies because of all these safety standards," Virk said.
Still, reports out of the United Kingdom, where shots entered arms earlier this week, reveal that some recipients suffered allergic reactions.
Virk said that issue should be studied but said the initial trials didn't pick up any similar side effects.
"We want to be very conscious about it. We want to be proactive about how we handle the allergies," Virk said. "There is more data to support safety than the two anecdotes of allergic reaction."
Federal regulators could comment on the issue Thursday as part of the Pfizer vaccine approval recommendation after British health authorities warned that those with a history of severe allergic reactions should skip the vaccine for now.
The most common side effects of both vaccines were fatigue, headache and body aches, most typically after the second booster shot. Most were mild to moderate, Virk said, and went away after seven days.
"We are all very eager to get to the other side of this pandemic," Minnesota Health Commissioner Jan Malcolm said. "We do believe that the vaccines coming to us are the critical tool that is going to allow that to happen."
Another 82 Minnesotans died from COVID-19 complications, along with 4,539 new confirmed cases, state health officials reported Wednesday.
The pandemic has claimed 4,109 lives in the state. Since Thanksgiving, there have been 734 deaths, an average of 54 new deaths reported each day.
Much of the toll has been among long-term care residents, who account for 66% of all deaths in the state. Fifty-one of the deaths reported Wednesday were residents of nursing homes or assisted living facilities.
Pressure on the state's hospitals has eased somewhat.
COVID-19 hospitalizations have dropped slightly, with 1,187 patients receiving noncritical care, a one-day decrease of 5%.
An additional 358 were in intensive care units, a decrease of one from the previous day.
Statewide, 90% of the 1,212 ICU beds are in use.
Minnesota is seeing about 87 new cases for every 100,000 residents. Although that is down from a high of 123.3 eight days earlier, it is still considered to be in the danger zone.
"The rate of case growth … is a full 60% higher than it was just a month ago," Malcolm said.
However, the Thanksgiving holiday has not shown signs so far that it sparked a new wave of infections.
"We hope and are perhaps getting some early signs that the increase we expected from Thanksgiving was moderated by people changing their plans," Malcolm said.
Still, it could take four weeks for any impacts to play out, although case numbers may be difficult to interpret because Minnesota ordered bars, restaurants, gyms and entertainment venues to shut their doors a week before the holiday.
Minnesota officials have prioritized that the first vaccine doses will go to health care workers and long-term care residents. But with 500,000 people in those two groups and 183,400 shots expected to be delivered this year, the list has been winnowed down to target those at highest risk.
The Mayo Clinic will focus its first vaccination efforts on people who work in COVID-19 units, the emergency room and emergency medical services personnel.
"As we get more and more vaccine we will be expanding eligibility to more and more groups of health care personnel based on their occupational risk," said Swift, who helps lead the clinic's COVID-19 vaccine allocation work group.
Mayo is one of 25 sites in Minnesota that will receive vaccine shipments. Unlike smaller health care facilities, it has the specialized freezers to store the Pfizer vaccine, which must be kept at minus 94 degrees Fahrenheit.
It will ship vaccine to other facilities in the region, where vials can be stored for five days under normal refrigeration. But once the vial is tapped, it must be used within six hours.
The Moderna vaccine needs to be frozen, but it can be safely kept in a standard freezer. That vaccine accounts for 74% of all the doses Minnesota expects this year.
Since COVID-19 was first detected in the state in March, 363,719 have tested positive for the virus. Of those, 320,233 are considered to be no longer infectious and don't need to be isolated.
A total of 39,591 test results were reported to the Minnesota Department of Health on Tuesday, a one-day increase of 44%.