Influenza Update

December 28, 2018

Tracking the disease from 2010 to the end of 2018.

The 2017-2018 flu season-one of most severe in recent U.S. history-drove home the need for increased vaccinations and for current data on the illness and its spread. Fortunately, the CDC, Walgreens, and other entities track the areas of the country where influenza is most severe and hospitalizations and mortalities attributed to the flu, and also provide updates on the effectiveness of anti-influenza drugs against the circulating influenza strains.

Walgreens Flu Index

Using weekly retail prescription data for antiviral flu drugs across Walgreens and Duane Reade stores nationwide, Walgreens Flu Index ranks the top 10 states as well as the top 10 designated market areas (DMAs) with flu activity by those experiencing the greatest gains in activity week-over-week.

“The Walgreens Flu Index can help pharmacists educate patients on the prevalence of flu activity in their communities, stressing the importance of getting the flu shot to help protect your- self and others from influenza,” Dorothy Loy, PharmD, director of immunizations at Walgreens, tells Drug Topics.

The data for the index, which was launched in December 2014, is analyzed at state and geographic market levels to measure absolute impact and incremental change of antiviral medications on a per store average basis, Loy says.

Walgreens updates the index each week during the flu season, with the turnaround time in data at just a few days, according to Loy.

Weekly U.S. Influenza Surveillance Report

The CDC’s Weekly U.S. Influenza Surveillance Report tracks influenza activity across all 50 states, and reveals the prevalence of flu strains by influenza A subtype (H1 or H3) and influenza B.

Especially helpful for pharmacists is the CDC’s antiviral resistance monitoring within the report. “All viruses tested since late May show susceptibility to the antiviral drugs oseltamivir [Tamiflu], zanamivir [Relenza], and peramivir [Rapivab],” CDC wrote in its November 24 report. Xofluza (baloxavirmarboxil) will also be available this flu season.

Data for CDC’s weekly surveillance report comes from WHO and National Respiratory and Enteric Virus Surveil- lance System (NREVSS) collaborating laboratories (which include both pub- lic health and clinical labs).

The labs, located in all 50 states, Puerto Rico, Guam, and the District of Columbia, report the total number of respiratory specimens tested for influenza and the number positive for influenza by virus type, CDC explains on its web site.

The Epidemiology and Prevention Branch in the Influenza Division at the CDC then collects and compiles the data and produces FluView, a weekly influenza surveillance report, and FluView Interactive, which allows for more in-depth exploration of influenza surveillance data-such as flu activity during past seasons.

The information allows CDC to track influenza-related illness, find out when and where flu activity is occurring, determine which viruses are circulating, detect changes in viruses, and measure the impact influenza is having on hospitalizations and deaths, Kristen Nordlund, a CDC spokesperson, tells Drug Topics.

There is a two-week lag time in the weekly influenza surveillance reports, Nordlund says. Influenza surveillance data collection is based on a reporting week that starts on Sunday and ends the following Saturday of each week. Participants summarize weekly data and submit it to CDC by Tuesday after- noon of the following week.

Other organizations and companies provide influenza prevalence reports. In partnership with the Weather Channel, U.S. Theraflu’s Cold and Flu Tracker aggregates social media mentions and community crowdsourcing to develop its “Sickscore,” an “easy-to-understand, real-time threat level of contagious cold and flu activity near you,” according to the web site.

Another influenza tracking resource is Flu Near You, created by Harvard, Boston Children’s Hospital, and the Skoll Global Threats Fund. Using crowd-sourced data from thousands of participants across the nation, the site lists flu activity for the past 7 days by state. Site visitors can also view the CDC’s weekly influenza data across the United States.

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