CDC Flu News: March 23, 2019

The ‘peak’ flu season in the USA may have passed, according to new data from the Centers for Disease Control and Prevention (CDC). 

During Week #12, only 20 states reported high influenza-like-illness (ILI) activity.

And, the proportion of outpatient visits for ILI decreased to 3.8 percent but remains above the national baseline of 2.2 percent. 

Nationally, during the most recent three weeks, influenza A(H3) viruses were reported more frequently than influenza A(H1N1)pdm09 viruses in all 10 HHS Regions. 

Influenza A(H1N1)pdm09 viruses predominated from October to mid-February and influenza A(H3N2) viruses have been more commonly identified since late February. Small numbers of influenza B viruses have also been reported. 

Additionally, the CDC confirmed just 1 new influenza-associated pediatric death. The total number of pediatric deaths related to the flu now totals 77 during the 2018-2019 season.

This data is actually good news when compared with the 2017-2018 flu season’s 185 pediatric deaths.  

As of March 29th, the CDC is now estimating the current flu season’s impact since October 2018 as follows:

• 31,200,000 – 35,900,000 symptomatic illnesses
• 14,400,000 – 16,800,000 medical visits
• 419,000 – 508,000 hospitalizations
• 28,000 - 46,800 influenza-related deaths

The Week #12 report included these flu season indicators for the week ending March 23, 2019:

• Viral Surveillance: The percentage of respiratory specimens testing positive for influenza viruses in clinical laboratories decreased. The majority of influenza viruses characterized antigenically are similar to the cell-grown reference viruses representing the 2018–2019 Northern Hemisphere influenza vaccine viruses.
• However, an increasing proportion of influenza A(H3N2) viruses are antigenically distinguishable from A/Singapore/INFIMH-16-0019/2016 (3C.2a1), a cell-propagated reference virus representing the A(H3N2) component of 2018-19 Northern Hemisphere influenza vaccines.
• Antiviral Resistance: The vast majority of influenza viruses tested (>99%) show susceptibility to oseltamivir and peramivir. All influenza viruses tested showed susceptibility to zanamivir.
• All 10 regions reported ILI at or above their region-specific baseline level.
• ILI State Activity Indicator Map: 20 states experienced high ILI activity; Puerto Rico and 13 states experienced moderate ILI activity; New York City, the District of Columbia and seven states experienced low ILI activity; 10 states experienced minimal ILI activity, and the U.S. Virgin Islands had insufficient data.
• Geographic Spread of Influenza: The geographic spread of influenza in Puerto Rico and 34 states was reported as widespread; 14 states reported regional activity; the District of Columbia and two states reported local activity; the U.S. Virgin Islands reported sporadic activity, and Guam did not report.
• Influenza-associated Hospitalizations: A cumulative rate of 52.5 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported. The highest hospitalization rate is among adults 65 years and older (167.0 hospitalizations per 100,000 population).
• Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was above the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.

The annual influenza virus remains one of the world’s greatest public health challenges. Every year across the globe, there are an estimated 1 billion flu cases, of which 3 to 5 million are severe cases, resulting in 290,000 to 650,000 influenza-related respiratory deaths, says the World Health Organization (WHO). 

The WHO recommends annual influenza vaccination as the most effective way to prevent influenza.

Vaccination is especially important for people at higher risk of serious influenza complications.

In the USA, antiviral medications and various flu vaccines remain available in most pharmacies.

The CDC Vaccine Price List provides private sector vaccine prices for general information. And, flu vaccine discounts can be found here.

Recent flu news:

• ‘When’ is Not As Important Regarding Flu Shot Timing
• Inactivated Influenza Vaccines Reported Safe for Cancer Patients on Immune Checkpoint Inhibitors
• FluNet Summary

Vaccines, like any medicine, can have side effects. Vaccine patients are encouraged to report negative side effects of vaccines to the CDC.

Note:  All CDC data are preliminary and may change as more reports are received. The CDC uses a model to estimate the numbers of influenza illnesses, medical visits, and hospitalizations in the United States.