This week’s Centers for Disease Control and Prevention (CDC) FluView report shows 43 states experiencing either high or widespread flu activity, mostly attributed to H3N2 viruses. Consequently, employers can expect elevated rates of worker absence.
Patient visits to doctors for influenza-like illness are almost even with the peak of 2012-2013 season, the last time H3N2 viruses predominated. Relatively higher flu hospitalization rates seen so far this season are similar to what has been observed during some past H3N2-predominant seasons.
The CDC continues to encourage influenza vaccination and prompt treatment with flu antiviral drugs, especially for people at high risk of serious flu complications including those 65 and older, children younger than 5, pregnant women, and individuals with compromised immune systems and certain other medical conditions.
In the past, H3N2-predominant seasons have been associated with more severe illness and higher mortality, especially in older people and young children, compared to H1N1- or B-predominant seasons. Between 1976 and 2007, for example, the CDC estimates that an average of 28,909 people died from flu during H3N2 seasons, compared to 10,648 people during non-H3N2 predominant years. Estimates of the number of flu deaths among people older than 18 are not available for this season; only pediatric flu deaths are nationally reportable.
Most of the H3N2 viruses circulating are “drifted” or different from the H3N2 vaccine virus, suggesting that the effectiveness of this season’s flu may be diminished. In addition to vaccination, public health officials recommend good hygiene practices to prevent the spread of flu. This includes washing hands frequently with soap and water for 20 seconds, covering one’s nose and mouth when coughing or sneezing, immediately disposing of tissues and staying home when ill.