Dec. 2, 2008 -- Although most college students are part of the 17 percent of Americans not included in the Centers for Disease Control and Prevention's vaccine recommendations, a new study suggests that they may be among the major beneficiaries of a flu shot.
The study, in this weeks issue of the Archives of Pediatric and Adolescent Medicine, found that college students who have been immunized against the flu were 30 percent less likely to contract an influenza illness, and were also less likely to miss class or become unable to complete work because of flu-like illness.
"Influenza-like illness is responsible for a substantial disease burden among college students, and vaccination is associated with substantial benefits," said Dr. Kristin Nichol, chief of medicine at the Minneapolis VA Medical Center and one the study's authors.
The researchers conducted an online survey of University of Minnesota students at the Twin Cities campus for four flu seasons, with each year's survey beginning in October and ending in April. For the final year of the study, researchers also collected data from students at St. Olaf's college in Northfield, Minn.
In addition to the 30 percent reduction in flu illness, vaccinated students were 47 percent less likely to visit a doctor for flu, 32 percent less likely to miss class and 47 percent less likely to do poorly on a test.
In addition to the reduced illnesses for the students themselves, the study authors noted that immunizations of college students could help keep influenza from spreading.
"They're a population that has interaction and access with lots of folks in the community." said Dr. Edward Ehlinger, director of the University of Minnesota's health service and another of the study's authors.
Ehlinger noted that the communities would not be the only ones affected by students carrying the flu virus.
"During the peak of the flu season, they're traveling all over the world," he said. "They're a perfect vehicle to spread influenza around."
While praising the overall study, Dr. William Schaffner, chairman of the department of preventive medicine at Vanderbilt Medical School noted a few complications with the study.
"Students who are much more organized in their lives," and are more likely to get the flu vaccine, "are going to be the ones that go to class," he said. "The results are consistent with those from other studies. But looking at this paper, that would be the issue."
Minneapolis' Nichol conceded that while the message of the study remains, there were some difficulties in controlling how similar the unvaccinated and vaccinated groups of students were.
"There is always the possibility of what we call 'residual confounding' in a study that is not a clinical trial," she said.
While Nichol said she would encourage college students to get vaccinated against the flu, she stopped short of saying the CDC should change its flu shot recommendations to include everyone.
"I certainly believe that studies like this help to inform those discussions, as they consider whether or not we should expand recommendations into other groups," Nichol said.
Certainly, college students saw stronger benefits from the flu vaccine than other groups, particularly in years where the vaccine was not a great match with the dominant flu strain.
While comparing studies that looked at different results is difficult, the college students in the study appear to have fared better than the toddlers in a recent one that looked at some of the same seasons. In that study, vaccination did not appear to reduce hospital visits.
But that is to be expected.
"It's not inconsistent that these young vigorous adults who have vigorous immune systems might be better protected than those young children," Vanderbilt's Schaffner said.
He noted that the college students are more likely to have been exposed to the virus, meaning their immune systems are more primed.
While the University of Minnesota has its vaccine covered under the student health plan and St. Olaf College charges a small fee, researchers declined to make a comparison between the two institutions.
But Minnesota's Ehlinger said that a free vaccine certainly made it easier to get more students immunized.
If students had to pay, "we wouldn't be getting the same numbers we're getting," he said.
Study researchers believe that increased vaccine use will benefit college students in other ways.
"If we want to get to universal coverage with immunization, a good place to do that is with college students," Ehlinger said, adding that vaccination in college would give them the habit of being vaccinated later in life.
Ehlinger also noted that students at state schools like Minnesota have half their tuition paid for by the state's citizens, and getting them immunized would keep them in the classes that taxpayers were covering.
"Keeping students in class is a good investment that all of us have in college students," he said.