Although flu cases have started to decrease since its peak early this winter, flu season may continue well into late Spring. The CDC warns a second wave of flu may be upon us as Influenza B is making the rounds.
Although first bombarded with H3N2 “A” strain influenza, Americans appear to be reporting more “B” flu cases this time of year, comprising more than 58% of cases lab-identified.
And young children are especially susceptible to B strain viruses.
5 pediatric flu-related deaths have been reported this week. The CDC cites 133 influenza-related pediatric deaths for the current 2017-2018 season.
According to the CDC:
Overall, influenza A(H3) viruses have predominated this season. However, in recent weeks the proportion of influenza A viruses has declined, and during week 11, influenza B viruses were more frequently reported than influenza A viruses.
Week 11 (March 11-17, 2018) has seen the following:
The proportion of outpatient visits for influenza-like illness (ILI) was 2.7%, which is above the national baseline of 2.2%. Nine of 10 regions reported ILI at or above region-specific baseline levels. Six states experienced high ILI activity; nine states experienced moderate ILI activity; New York City, Puerto Rico, the District of Columbia, and 17 states experienced low ILI activity; and 18 states experienced minimal ILI activity.
The trivalent and quadrivalent flu vaccines both protected against Influenza B as well as the A strains of H1N1 and H3N2 this year. However, flu shot efficacy proved poor for the 2017-18 season, being approximately 30% effective. Moreover, flu viruses can mutate as the season progresses.
It is not uncommon for one to be infected with the flu twice by two different strains circulating during the season.
What’s concerning is allergy season is beginning to overlap with flu season. Those with allergies may have a temporary weakness in their immune system, making them more susceptible to catching a cold or flu.