This year’s respiratory virus season witnesses a surge in the cases induced by a mutated version of an influenza A strain. The CDC’s latest FluView report indicates more than half of the states in the country reporting ‘high’ or ‘very high’ levels of flu-like illnesses for the week ending Dec. 20. It is anticipated that a further spike will be seen in the coming weeks, particularly in the aftermath of holiday travels and gatherings.
Around 19,000 patients confirmed with flu were hospitalized in the week culminating Dec. 20, manifesting a 91% surge from the preceding week, as per CDC data. The consistent rise in hospitalization from 3.1 to 5.6 per 100,000 population week-over-week echoes the CDC’s prediction of a similar trend of flu admissions as felt during the last season. This elevation was severe in nature since 2010, affecting between 610,000 and 1.3 million people affording to the CDC’s estimates.
Including eight pediatric flu deaths, the CDC estimates at least 7.5 million flu cases, 81,000 hospitalizations, and 3,100 deaths so far in this season. For the week till Dec. 20, around 29 states along with New York City and District of Columbia, which are reported individually by HHS, exhibited ‘high’ or ‘very high’ levels of flu-like diseases. In totality, over 6% outpatient visits for the week were due to respiratory ailment, higher than the national baseline of 3.1%.
Simultaneously, a steady rise is seen in the Emergency Department (ED) visits for the flu. The percentage of ED visits due to flu-like symptoms increased from 2.9% to 5.4% for the week ending Dec. 20, with children being especially prone to the illness. Flu accounted for 12.3% of ED visits for children and infants upto 4 years of age and 17% for those aged between 5 to 17.
New York state reported more than 71,000 cases for the week till Dec. 20, being the highest recorded since the initiation of tracking in 2004, according to health officials. A similar situation was observed at Northwell Health, New Hyde Park, where there was an increase in cases straining their emergency, urgent care and primary care practices.
Public health experts believe that a mutated H3N2, an influenza A subtype called ‘subclade K’, might be the cause of the recent spike in the flu cases. This strain acquired several mutations over the summer, resulting in more efficient spreading and evasion of existing immunity. Though not correlated with a severe illness, the strain doesn’t closely match this year’s flu vaccine. However, experts still emphasize on the significance of vaccination for reducing the severity of the diseases specifically among high-risk populations. The frequently reported influenza viruses so far this season seem to be H3N2 viruses, according to CDC data.