Small-particle aerosolization of live attenuated influenza vaccine virus

A new study suggests that patients with influenza can emit small virus-containing particles into the surrounding air during routine patient care, potentially exposing healthcare providers to influenza. Published in the Journal of Infectious Diseases, the findings raise the possibility that current influenza infection control recommendations may not always be adequate to protect providers from influenza during routine patient care in hospitals.

94 patients were screened for flu-like symptoms during the 2010−2011 influenza season. Study participants had been admitted to the emergency department (52 patients) or an inpatient care unit (42 patients) of Wake Forest Baptist Medical Center, where vaccination for influenza is mandatory for healthcare providers. Of the 94 patients enrolled, 61 patients (65 percent) tested positive for influenza virus. Twenty-six (43 percent) released influenza virus into the air. Five patients (19 percent) emitted up to 32 times more virus than others. This group of patients with influenza, described by the researchers as “super-emitters,” suggested that some patients may be more likely to transmit influenza than others. High concentration of influenza virus released into the air was associated with high viral loads in nasopharyngeal samples. Patients who emitted more virus also reported greater severity of illness.