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January 31, 2019

It's safe to give hospitalized patients a flu vaccine, a new study suggests

Daily Briefing

    Receiving an influenza vaccination does not make hospital patients more likely to develop a fever or require additional hospital visits, according to a study published this month in the Mayo Clinic Proceedings.

    How to avoid the flu when you fly

    According to Reuters, CDC recommends virtually all U.S. residents ages six months and older receive an annual flu vaccination by the end of October, but about 50% of U.S. residents do not consistently follow CDC's recommendation. In some cases, physicians are reluctant to vaccinate hospitalized patients out of concern already sick patients could develop complications that would require additional care, Reuters reports.

    Study details

    For the study, researchers analyzed data from three consecutive flu seasons to determine the effects in-hospital flu vaccinations had on a patient's risk of developing a fever or need for additional care via an outpatient setting or hospital readmission. The data included 290,149 U.S. hospitalizations, involving 255,737 patients. Of the patients:

    • Nearly 50% were vaccinated against the flu before their hospital stays;
    • 27% were unvaccinated for the flu season;
    • 16% were vaccinated during their hospital stays; and
    • About 7% were vaccinated after they were discharged from the hospital.

    The researchers did not design the study to determine whether or how a flu vaccination's timing might directly affect complications such as fever or hospital readmissions, Reuters reports. In addition, the researchers noted that the study did not distinguish between planned and unplanned hospital and doctor visits that occurred during the first week of patients' discharge from the hospital

    No association between in-hospital flu vaccine and adverse effects

    The researchers found no meaningful difference in risks of fever, needing a checkup for infections, requiring outpatient visits, and hospital readmissions among patients who received a flu vaccination during their hospital stays, those who were vaccinated outside of their hospital stays, or those who never received a flu vaccination.

    Study lead author Sara Tartof of Kaiser Permanente Southern California said, "When someone is hospitalized, that means that they are in a very vulnerable health situation. Clinicians may not want to vaccinate at this time due to concerns that it could complicate care, or make a very sick patient feel even worse. However, we did not find this to be the case."

    Kevin Schwartz, a researcher at Public Health Ontario and the University of Toronto who was not involved in the study, said, "This study is a nice reminder that patients who get admitted to hospital who are unvaccinated during flu season can be safely vaccinated before discharge." He said, "There are many studies showing that the yearly flu shot is safe and well tolerated by most patients, even those with significant medical problems." Schwartz added, "Everyone is encouraged to get a flu shot every year in the fall before flu season as the most effective tool to prevent influenza and its associated complications for yourself and those around you" (Rapaport, Reuters, 1/25).

    How to avoid the flu when you fly

    Download this infographic to learn about both the obvious and less obvious locations where germs on planes are rampant.

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