Flu Activity is Increasing in the U.S. but remains ‘very low’

Flu Activity is Increasing in the U.S. but remains ‘very low’

The CDC does not consider the influenza season to have started yet.

Although flu activity continues to increase in the United States, it remains low enough that the CDC does not consider the flu season to have started yet, a CDC expert said.

“While the proportion of respiratory specimens testing positive for influenza is increasing, it is ‘still very low,’ Lynnette Brammer, MPH, who leads the domestic surveillance team in the CDC’s Influenza Division. “Determining when the flu season starts each year involves a careful review of existing data. This season may be more challenging than usual given ongoing spread of COVID-19.”

Despite fears of so-called COVID-19 and influenza “twindemic,” there was an “unusually low” level of influenza activity in the U.S. last season. This is likely a result of the various measures taken to lessen the spread of coronavirus. Activity was so low that the CDC was unable to estimate the effectiveness of seasonal influenza vaccines. There was a lot of uncertainty for this season since COVID-19 restrictions became a bit more relaxed in certain areas and the possibility that immunity to some flu viruses has waned due to less exposure. The CDC says, so far, that activity has remained below the level considered for the U.S. can be in an “influenza pandemic.”

According to the latest CDC FluView data, data the week ending on December 4, 2.5 percent of outpatient visits in the U.S. were for respiratory illnesses. This matches the U.S. baseline for influenza—like illness (ILI), which the CDC develops “by calculating the mean percentage of patient visits for influenza—like illness during non-influenza weeks for the most recent three seasons,” Brammer said.

Brammer explained that the CDC is currently excluding a chunk of the COVID-19 pandemic—from March 2020 through September 2021—and adding two standard deviations to develop the baseline for circulating ILI.

“The flu season is said to start when indicators used to monitor influenza activity are above baseline consistently for a number of consecutive weeks,” she said. “While ILI activity is one of those factors that CDC looks at, it is not the only factor. ILI can reflect other respiratory virus activity.”

According to an article, because of this, the CDC follows the proportion of respiratory specimens that have tested positive for the flu in clinical and public health laboratories “to ensure that ILI activity is actually a result of influenza virus and not some other respiratory virus.”

The majority of detected infections in recent weeks were caused by influenza A(H3N2) with about 80 percent of cases occurring in children and young adults between the ages of five and 24 years old.

Download Center

  • The Ultimate Guide to OSHA Recordkeeping

    When it comes to OSHA recordkeeping, there are always questions regarding the requirements and in and outs. This guide is here to help!

  • Lone Worker Safety Guide

    As organizations digitalize and remote operations become more commonplace, the number of lone workers is on the rise. These employees are at increased risk for unaddressed workplace accidents or emergencies. This guide was created to help employers better understand common lone worker risks and solutions for lone worker risk mitigation and incident prevention.

  • Online Safety Training Buyer's Guide

    Thinking of getting an online safety training solution at work but not sure how to evaluate different solutions and find the one that's best for your company? Use this handy buyer's guide to learn the basics of selecting online safety training and how to use it at your workplace.

  • SDS Software Buyer's Guide

    Whether this is your first time shopping for online SDS software or you’re upgrading from a legacy solution, this guide is designed for you to use in your search for the safety management solution that works best for you and your company.

  • Risk Matrix Guide

    Risk matrices come in many different shapes and sizes. Understanding the components of a risk matrix will allow you and your organization to manage risk effectively.

  • Vector Solutions

OH&S Digital Edition

  • OHS Magazine Digital Edition - January February 2022

    January February 2022


      Industrial Facility Safety from the Loading Dock to the Plant Interior
      Tiny Particles: Big Booms
    • OIL & GAS
      Creating a Culture of Safety
      Innovative, Comfortable Hand Protection Option for Workers
    View This Issue