An estimated 115,000 Minnesotans with weakened immune systems are eligible for another round of COVID-19 vaccine since federal health officials gave final approval to third shots on Friday.

But the third jab of the Pfizer or Moderna vaccines is not for everyone, such as those with common chronic conditions like diabetes, hypertension or high cholesterol.

The Centers for Disease Control and Prevention said the third shot can be given to organ or stem cell transplant recipients, cancer patients, those with uncontrolled or advanced HIV, people being treated with high-dose corticosteroids or other immune-suppressing drugs and other diseases that suppress the body's ability to fight infections.

Most people who are eligible are likely to be under the regular care of a doctor who is monitoring their condition.

The additional shot was added because studies showed that the Pfizer and Moderna COVID-19 vaccines were less effective in the immunocompromised population. The Johnson & Johnson vaccine was not included in the federal government's review.

"The recommendations that are being made right now are based on strong data," state infectious disease director Kris Ehresmann said. "Before booster doses for the general public would be recommended we would need to have clear data for those recommendations.

"The idea if two is good, three is better is not necessarily true" in all cases, she added. "In the absence of a recommendation, just seeking additional vaccine is not the right thing to do."

The vaccines are still effective in those who do not have compromised immune systems.

"The vaccines continue to do the job that we need them to do and that is to prevent severe disease, hospitalizations and death," Ehresmann said.

The number of weekly first doses administered in Minnesota has jumped 129% from a month ago.

That increase was partly driven by the state's offer of $100 Visa gift cards to the newly vaccinated. More than 44,000 Minnesotans have registered to receive the card, but people have to sign up on the state's website before the offer expires at 11:59 p.m. on Sunday.

Ramsey County announced on Friday its own $100 Visa gift card program for people who get their first shot at a clinic operated by the St. Paul-Ramsey County Public Health Department.

The incentive program, which started Friday, is open to everyone, regardless of county residence. The cards will be handed out at the clinic. Recipients are still eligible for the state program until it expires, meaning a potential windfall of $200 for the newly vaccinated.

"We hope these gift cards are the extra incentive for people to take the most effective step in protecting themselves and their families by getting the COVID-19 vaccine at one of our clinics at schools, community centers, or pop-up sites at events and community locations," said county public health director Sara Hollie.

About 35% of vaccine eligible Minnesotans are not fully vaccinated, and when children under 12 who are not yet eligible are included, the number increases to 45%.

Another 1,336 confirmed COVID-19 infections and six deaths were announced by state health officials Friday, bringing the pandemic total to 624,851 cases and 7,729 fatalities.

The testing positivity rate has risen to 5.1%, putting it above the cautionary threshold, while the per capita case growth rate stands at 15.4%, which public health officials consider to be in the high risk category.

"We definitely don't like the trends," Minnesota Health Commissioner Jan Malcolm said. "It is concerning to note how quickly we have gone up into higher transmission categories."

More than half of Minnesota's 87 counties are now considered to have high rates of COVID-19 virus transmission and most others have substantial transmission, based on CDC measures that include case growth rate and testing positivity rate.

Only seven counties are considered to have moderate transmission and none have low rates.

The CDC recommends that everyone wear masks indoors in areas that have substantial or high COVID-19 transmission. When it issued its guidance on July 27, only 14 Minnesota counties fell into those categories.

Malcolm said the rapid spread has been fueled by the highly infectious delta variant.

"The delta variant is so widespread and growing quickly it now accounts for 95% of the sequenced specimens," she said.

The approval of the third shot for those with weakened immune systems could help protect more people as the delta variant continues to circulate.

"This announcement is really a welcome development in helping to protect some of the most vulnerable Minnesotans," Malcolm said.

The CDC recommendation says that the newly eligible should receive the same vaccine brand and at least 28 days after the second.

Malcolm said the state has plenty of vaccine available for the third shot as well as those who are unvaccinated. Instead of receiving a weekly allotment, states can now order what they need at any time.

"This is now a much more rapid and flexible system," she said.

Glenn Howatt • 612-673-7192