The 2017-18 influenza season peaked in early February and is now on the decline, according to a data published by the CDC March 3rd. Here are some summary points.
The percentage of outpatient visits for influenza-like illness was 5% for the week ending Feb. 24th–a 1.4% decline from the week prior. Despite the decrease, flu activity is expected to continue for weeks.
The CDC tallied 23,324 laboratory-confirmed flu-associated hospitalizations from Oct. 1, 2017, through Feb. 24, 2018.
Influenza A has been most frequently identified virus type in positive specimens this flu season, the majority of which (86.6%) attributable to the H3N2 strain. This strain is known to cause more severe illnesses in the elderly and young children. “While H3N2 viruses remain predominant overall this season, the proportion of B viruses versus A viruses is now almost even,” said the CDC in a summary of the new data. “In recent weeks, B viruses have been increasing while H3N2 viruses have been decreasing.”
The CDC reported an increase in count of pediatric flu deaths for the 2017-18 flu season by 17, bringing its total to 114, surpassing the 110 pediatric flu deaths reported for the 2016-17 flu season.
In recent weeks, B viruses have been increasing while H3N2 viruses have been decreasing. Early vaccine effectiveness estimates show that flu vaccine has reduced the risk of having to go to the doctor due to flu by 36% overall through February 3, 2018.
Vaccine effectiveness against H3N2 viruses was 25%. VE against H1N1 67% and VE against B viruses was 42%.