This flu season has hit a little late this year, with CDC issuing a health advisory on February 1 noting that severe influenza illnesses have been reported in recent weeks. Clinicians are encouraged to continue efforts to vaccinate patients this season for as long as the influenza viruses are circulating and promptly start antiviral treatment in severely ill and high-risk patients for suspected or confirmed disease.
The agency reported that H1N1pdm09 viruses have predominated in recent weeks, and severe respiratory illnesses have occurred in young to middle-aged adults. Some patients have required hospitalization in the ICU and some fatalities have been reported. Most of these patients were reportedly unvaccinated. H1N1pdm09 viruses have caused severe illness in children in the past, and CDC expects that influenza activity will increase further in the coming weeks. A total of seven influenza-associated pediatric deaths have been reported during the 2015–16 season thus far.
CDC listed a variety of recommendations for clinicians, including continuing efforts to vaccinate all eligible patients (i.e., aged 6 mo and older) this season and to promptly start antiviral treatments when appropriate. All available vaccine formulations this season contain A(H3N2), A(H1N1)pdm09, and B virus strains, and CDC does not recommend one influenza vaccine formulation over another. Antiviral treatments are recommended to be initiated as soon as possible—ideally within 48 hours of symptom onset. The agency noted that decisions to start antiviral treatments should not wait for laboratory confirmation of influenza, especially in patients who are hospitalized, have severe illness, or are at high risk for influenza complications. High-risk patients include children younger than 2 years of age, adults aged 65 years and older, pregnant women, residents of nursing homes or other chronic care facilities, American Indians/Alaska Natives, and those who are immunosuppressed, are morbidly obese, or have select comorbid conditions.
Detailed recommendations released by the CDC can be accessed at: http://content.govdelivery.com/accounts/USCDC/bulletins/133a8ad.