My name is Kristen Feemster. I am a pediatric infectious diseases physician at the Children's Hospital of Philadelphia. I'm here today to talk about influenza. There have been almost daily news stories regarding our current influenza season suggesting unusually high prevalence and acuity. Influenza activity started early this season and has been brisk. Currently, 47 states report widespread activity, and 40 states report moderate to high influenza-like illness activity, consistent with a severe influenza season. It is difficult to determine whether flu activity has plateaued or peaked, and it is certainly possible that the perceived high acuity and prevalence may be exacerbated by high circulation of other respiratory pathogens, especially respiratory syncytial virus (RSV). We also have had relatively mild influenza seasons since the 2009/2010 H1N1 pandemic.
So, what to do during this time of high influenza prevalence, particularly when we're confronted with many questions and concerns from patients and families? It is necessary to maintain high vigilance. Anyone presenting with an influenza-like illness should be suspected of having influenza. Other infections can present with similar symptoms, including some that are also widely circulating at this time, which can challenge diagnosis and treatment decisions. However, when influenza is suspected in the setting of high community activity, influenza is a likely diagnosis. There have been some studies to indicate that clinical symptoms have a high positive predictive value during a severe influenza season.
When to do diagnostic testing? Testing may be useful in some settings, especially in hospital settings when you have patients with severe respiratory symptoms and suspected influenza but with no identified etiology. But for the most part in community settings, clinical presentation can be used to guide diagnosis.
When a diagnosis is suspected or made, the next decision is regarding treatment. Treatment is indicated and an important management modality particularly to prevent progression to severe disease and the development of influenza complications. In the outpatient setting testing, it is most effective when it is initiated within 48 hours of onset of symptoms. In the hospitalized setting, you can initiate treatment at any time, which has been shown to be efficacious in preventing progression of symptoms.
I'd like to talk about prevention. Vaccination remains our most effective prevention measure. It is recommended for all individuals over the age of 6 months, with particular focus on those who are at risk for influenza complications and the most severe disease. There are 2 trivalent inactivated influenza products available: regular and high dose. Additionally, there is an intradermal preparation that is approved for 18- to 64-year-old individuals. There is a live attenuated influenza vaccine available for all 2- to 49-year-olds who are healthy and not pregnant. As for contraindications, egg allergy is no longer an absolute contraindication. If someone has experienced hives after egg exposure, they can receive the trivalent inactivated vaccine under provider supervision.
We often receive questions regarding vaccine efficacy. It depends, of course, on the matching between the circulating strains and the vaccine. This year, there is a very good match. The majority of cases are caused by influenza A and 99% of these are the H3N2 strain that is contained in the vaccine.
Lastly, we have also gotten some questions regarding vaccine supply, and this has been covered in the news as well. There have been no manufacturing issues related to this year's supply. Vaccine should be available for all of those who need it, though they may need to go to another location, another pharmacy, in order to find it.
In summary, yes -- this is a severe influenza season, but it is not more severe than those we have seen in the past. We have the tools at hand to diagnose, treat, and prevent.
© 2013 Children's Hospital of Philadelphia and Medscape
Cite this: Influenza in Kids: Should You Test? - Medscape - Feb 19, 2013.