After reading about influenza-related deaths and hospitalizations, people often ask me whether or not flu victims had been vaccinated.

It’s a tough question to answer, because the Minnesota Department of Health does not disclose vaccination status when it reports flu-related hospitalizations or pediatric deaths. The state does look back on the vaccine status of victims, but well after the peak flu season.

And yet the question has come with increased intensity this flu season, because the vaccine is poorly matched to the flu strains that are circulating. The U.S. Centers for Disease Control and Prevention reported Thursday that the vaccine has only been 23 percent effective, though it nonetheless has prevented many illnesses and deaths.

And Minnesota has seen a disproportionate number of child deaths; four of 26 children who died from flu infections in the U.S. so far this winter have been from this state.

So I asked Children’s Hospitals and Clinics of Minnesota for an answer to this reader question, and discovered that a few children have died or needed intensive hospital care despite vaccinations. But the hospital’s top infectious disease expert, Patsy Stinchfield, said the proportion of severely flu-infected children who were vaccinated doesn’t appear different from other flu seasons.

Of 27 children admitted to Children’s intensive care units due to severe flu complications, one third were babies and too young to be vaccinated. Half had not been vaccinated at all or hadn’t received a second pediatric dose required for full immunity. One in five of these sickened children were vaccinated, although some got infected in the two-week time period before their vaccinations were fully effective.

Only one of the three patients at Children’s who died of their flu infections had been vaccinated early in the flu season. In all, Children’s clinics, emergency departments and hospitals have treated 866 confirmed flu cases so far. The proportion who were infected despite vaccination will be tallied later this year.

Stinchfield said it is natural to wonder about whether children died or suffered severe infections despite vaccination. But even at 23 percent effectiveness, she stressed vaccination is important for children — not just for kids who receive shots, but for their infant siblings who need the “herd” immunity of those around them to be protected.

“Even though effectiveness is not 100 percent of where we want it to be,” she said, “it’s still a very worthwhile thing to be vaccinated, because it might be the thing that keeps kids out of the ICU.”