Norovirus & influenza update 1/17/17

January 17th, 2017

Norovirus

We are seeing an uptick in norovirus locally.  It only takes contact with a few particles to become infected. Remember also that the immunity from infection is very short lived – several months so you can have norovirus illness many times in your life. Norovirus illness can be serious, especially for young children and older adults.

Diagnostic:  methods focus on detecting viral RNA or antigen; RT-qPCR assays are the preferred laboratory method for detecting norovirus.

Treatment:  supportive; especially older people make easily become dehydrated.

Prevention:  People who have norovirus illness can shed billions of norovirus particles. You are most contagious:

  • when you are sick with norovirus illness, and
  • during the first few days after you recover.

Remember that food handlers (including those in nursing homes, healthcare etc) will need a work excuse to be off until 48 hours after the diarrhea has completely resolved.

Most people should stay home certainly while ill, but also for 48 hours after diarrhea stops – this might prevent wide spread transmission in the Fort.

Flu Update

According to the CDC, laboratory data suggest that influenza A (H3N2) viruses are predominating during the 2016-17 season, which are often are associated with more severe illness, especially in young children and older adults. Certain people are at greater risk for complications, including pregnant women, adults aged 65 or older, children younger than 2 years of age, and people with underlying health conditions like immunosuppression, asthma, diabetes, or heart disease. Influenza vaccination—and treatment—among high-risk patients is critical.

Early antiviral treatment in people with influenza can reduce serious flu-related complications such as pneumonia in outpatients and death in hospitalized patients. CDC recommends rapid empiric treatment of high-risk persons with influenza symptoms. Treatment is also recommended as early as possible for any patient with confirmed or suspected influenza who is hospitalized or who has severe, complicated, or progressive illness.

Don’t wait for lab confirmation, antiviral treatment should be started as soon as possible after illness begins, ideally within 48 hours of symptom onset. However, antiviral treatment may still provide some benefit in hospitalized patients even when begun after 48 hours of illness onset.  Antiviral treatment also can be considered on the basis of clinical judgment for previously healthy outpatients with confirmed or suspected influenza who are not in one of the high-risk groups, if treatment can be initiated within 48 hours of illness onset.

The three prescription antiviral medications recommended for treatment of influenza are oral oseltamivir, inhaled zanamivir, and intravenous peramivir. These neuraminidase inhibitors are chemically related and have activity against both influenza A and B viruses. Generic oseltamivir was approved by the FDA in August 2016 and became available in December.  To treat influenza, oral oseltamivir and inhaled zanamivir are usually prescribed for 5 days, although hospitalized patients may receive treatment for longer. Intravenous peramivir is administered in a single infusion over 15-30 minutes. Peramivir is approved for treatment in adults, zanamivir for treatment of children 7 years or older, and oseltamivir for treatment even in infants.

Antiviral resistance among circulating influenza viruses to any of the neuraminidase inhibitor antiviral drugs is currently low, but rare, sporadic cases of antiviral resistance can occur.

Questions call Deb McMahan, MD