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2017 Week 48 Flu Review Maps

Influenza, or flu, is a respiratory infection caused by a variety of flu viruses. The "flu" is a common catch-all term used for a variety of illnesses, but it correctly applies only to the upper respiratory disease caused by the influenza virus.

Estimates are that between 15% and 40% of the population will develop illness from influenza every year. An average of about 36,000 people per year in the United States die from influenza, and 114,000 per year have to be admitted to the hospital as a result of influenza infection. Anyone can get the flu (even healthy people), and serious problems from influenza can happen at any age. People age 65 years and older, people of any age with chronic medical conditions, and very young children are more likely to get complications from influenza.

For the most current information about influenza in Florida, please see Florida's Weekly Surveillance Report, the Florida Flu Review. Below is a summary of the current flu review.

Summary - Week 48: November 26 – December 2, 2017

State influenza and influenza-like illness (ILI) activity:

• Influenza activity has been steadily increasing over the last few weeks. In week 47:

• Visits to EDs among pregnant women increased notably and was well above levels observed during the previous two flu seasons at this time.

•  Five outbreaks were reported: (3) influenza, (1) ILI, and (1) respiratory syncytial virus (RSV); 32 outbreaks of influenza and ILI have been reported since the start of the 2017-18 season. More outbreaks have been reported so far this season than in previous seasons at this time, which may be an early indication of a more severe influenza season.

All regions are currently in RSV season. RSV activity remains high and well above previous seasons (see page 12).

National influenza activity:

• Influenza activity has continued to increase and was above the national baseline for the first time this season. The Centers for Disease Control and Prevention (CDC) noted that several flu activity indicators were higher than typically observed for this time of year.

As in Florida, influenza A (H3) has been the most common influenza subtype reported to the CDC. The CDC has continued to report extensive genetic diversity in the HA genes of influenza A (H3) viruses submitted to CDC for phylogenetic analysis.

Immunizations and prevention:

Flu vaccines can vary in effectiveness from season to season but they continue to be the best way to prevent influenza infection and serious influenza complications.

• Interim vaccine effectiveness (VE) estimates for Australia’s 2017 influenza season revealed very low VE estimates for influenza A (H3) viruses. VE estimates were higher for influenza A 2009 (H1N1) viruses (50%) and influenza B viruses (57%).

• VE estimates for the United States are not currently available, and while influenza A (H3) viruses have been most common so far this season, it is still unknown what viruses will predominate this season.

• Getting vaccinated is important because it also protects people around you, including those who are more vulnerable to complications from influenza infection and those who cannot get vaccinated themselves. To locate a flu shot near you, contact your physician, your local county health department, or use the Florida Department of Health’s flu shot locator:


• The CDC recommends the use of antiviral treatment as soon as possible for all persons with suspected influenza who are at higher risk for complications: children <2 years, adults age ≥65, and pregnant women, and those with underlying medical conditions; administer treatment within 48 hours of illness onset.

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