In Minnesota, health officials have reported 89 cases of COVID-19 infection in people who were fully vaccinated, according to the Star Tribune, the largest news outlet in the state.

The health officials said a small number of “breakthrough” cases can be expected because vaccines are not 100% effective.

Infectious disease expert Dr. Kristen Ehresmann told the news outlet, “We should not be fooled into seeing such a case as a reason to doubt the vaccine effectiveness.”

“Remember, a 95% effective vaccine still means we could expect to see infections in around 5 of every 100 people who get the vaccine,” she added.

More than 1.4 million residents in Minnesota have received at least one COVID-19 vaccine as of Wednesday. Of those, around 800,000 are considered fully vaccinated, meaning it has been 14 days since their final dose and the vaccine has had time to spark an immune response, according to Medscape.

The 89 COVID cases represent less than one-tenth of 1% of those who are fully vaccinated.

The officials have been reviewing the cases to determine if there are any similarities, Dr. Ehresmann said. For instance, if the cases stem from the same vaccination site, that could indicate whether there were any issues with a specific lot of vaccines or the site might have handled the vaccine doses incorrectly.

So far, none of those breakthrough cases have led to death. The patients tend to have mild illnesses.

Dr. Andrew Olson of the University of Minnesota Health told Star Tribune, “Yes, people get COVID, but people, in general, do overall better. We have seen that both in patients in our system who are hospitalized and patients who are not hospitalized.”

Recently, CNN reported that the CDC has been tracking breakthrough cases across the nation as more people are getting vaccinated.

In February and March, officials have reported breakthrough cases in Oregon, South Carolina, Florida, Texas, and Hawaii, per The Atlantic.

A CDC spokesperson told the newspaper, the agency will start reporting the number of breakthrough cases along with the locations or people who contract COVID-19 infection even after being fully vaccinated.

On Wednesday, public health officials in Idaho said they have identified “fewer than 100” breakthrough cases among the 250,000 people who have been fully vaccinated.

Dr. Scott Lindquist of Washington State Department of Health to the news outlet, “We know we will see breakthrough cases, it’s just what does the breakthrough case look like, who are they, where are they, and what vaccines — if any — show a higher rate of breakthrough.”

“We actually are in discussion with the CDC about how many breakthrough cases should Washington be expecting because we know that vaccine isn’t 100%,” he added. The article originally appeared Wednesday on Medscape Medical News.