Flu and Shigella Update 1/12/15

January 12th, 2015

Influenza
No surprise still seeing significant flu activity.

National

  • The proportion of outpatient visits for influenza-like illness (ILI) was above the national baseline for the sixth consecutive week.
  • CDC also continues to receive reports of flu hospitalizations and flu deaths.
  • Twenty-one pediatric deaths have been reported so far this season.
  • Influenza A (H3N2) viruses have been most common so far in the United States, accounting for more than 99% of all subtyped influenza A viruses reported to CDC from U.S. WHO and NREVSS collaborating laboratories.
  • H3N2-predominant seasons have been associated with more severe illness and mortality compared to H1N1- or B-predominant seasons, especially in older people and young children.
  • For example, CDC estimates that an average of 28,909 people died from flu during H3N2-predominant seasons, compared to 10,648 people during non-H3N2 predominant seasons.
  • So far, more than two-thirds of the influenza A (H3N2) viruses analyzed since October 1 are antigenically or genetically different from the H3N2 vaccine virus component this season. (See the FluView Activity Update below.)
  • The vaccine may not work as well against these different A (H3N2) viruses.
  • Two factors play an important role in determining the likelihood that flu vaccines will protect a person from flu illness: 1) the characteristics of the person being vaccinated (such as their age and health); and 2) the similarity or “match” between the flu viruses in the vaccine and those spreading in the community.
  • CDC is urging influenza vaccination for any persons who have not been vaccinated yet this season, as vaccine may still offer benefit. This includes people who may have already gotten the flu this season; flu vaccine protects against three or four different viruses and it’s possible that other viruses will circulate later in the season.
  • Antiviral drugs become even more important when circulating flu viruses are different from the vaccine viruses, which can mean that the vaccine doesn’t work as well in protecting against infection with those viruses.
  • Antiviral drugs are effective across all age and risk groups.
  • Studies show that antiviral drugs are under-prescribed for high risk people who get flu.
  • One study showed that less than one-fifth (19%) of patients who were at high risk for flu complications and presented for care within two days of symptom onset (i.e., the period of time when antiviral treatment is most beneficial) received a prescription for antivirals, regardless of laboratory testing for influenza infection (Havers, 2014).
  • The study demonstrates that clinicians are still more likely to prescribe antibiotics rather than antiviral medications to outpatients with flu, including to high-risk patients who would benefit from early empiric antiviral treatment.
  • Treating high-risk people or people who are very sick with flu with antiviral drugs is very important. It can mean the difference between having a milder illness instead of very serious illness that could result in a hospital stay.

Locally, we are investigating a number of deaths from flu – half of which occurred in unvaccinated older patients.

Shigella

Continue to see an increase in cases of Shigella – we have not determined a link as of yet. Please order susceptibilities when ordering stool cultures thru the Parkview system during this outbreak – a significant number of cases were resistant to Sulfa.  Do not use Septra or Bactrim a first line treatment for suspected cases.  Remember to get a work history as food handlers, healthcare workers and daycare workers must be treated and asymptomatic before they can return to work.

Questions, call Deb McMahan, MD