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Are the Guidelines for Tamiflu too Liberal? The Season of the Positive A and B Flu Tests

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I have practiced for a couple decades now and this is the first time that I am seeing so many positive flu tests despite patients having the vaccine. Normally, the influenza test shows only one strain but this year in 2019 we are all seeing two strains being positive on the test. What is happening?

This season brings many positive tests for both influenza A and B. Is it due to poor vaccination rates, inaccurate tests, the vaccine being ineffective, or the use of Tamiflu? Patients who were vaccinated in a timely manner are still presenting with positive flu swabs this season.

Understanding the complexity of viruses and their ability to mutate in any condition is helpful to understand the pathophysiology about this occurrence of being vaccinated yet still being flu positive. The CDC recommends safety in giving the Tamiflu and other anti-virals within the window period of 72 hours to decrease the replication of the virus and to shorten the lifespan of the symptoms. I wonder if our patients are using these neuramidase inhibitors correctly and if the use of these drugs is interfering with the effectiveness of the influenza vaccine? The FDA warns practitioners not to give the medication in combination with the live influenza vaccine as it will interfere with efficacy but so far there is no warning against use in conjunction with the other flu vaccines. Many practitioners will prescribe Tamiflu without a confirmed positive flu test for symptoms of the flu and I wonder if this will create more resistance? Already we know that the antiviral medications increase the risk of other viral infections during the season due to the suppression of the immune system.

Recently one of my healthy patients had a fever and had had the flu vaccine back in October and tested positive for both influenza A and B. I had to tell my patient that the vaccines do work and sometimes you still may get the flu but usually it is a milder form. Resistance has been shown to occur during or after treatment in immunosuppressed patients. However, this patient was not immunosuppressed. He was young and healthy.

I scrutinize that science has let us down with these positive flu patients and that these examples of illness likely generally do not promote vaccinations. Do we have to work more diligently now at encouraging our patients to continue to get vaccinated next year even after this failed vaccine attempt to prevent the flu?

I am really hoping that a better correlation between the effects of the antivirals used for the flu can be made within the next year and that practitioners will be able to understand if these pharmaceuticals are also interfering with the effectiveness of herd immunity and overall efficacy of the influenza vaccines pharmacodynamics and pharmacokinetics.

Currently the CDC guidelines for the prescribing of Tamiflu are bolded (CDC 2018). This medication is reserved for hospitalized patients, patients with severe, complicated or progressive illness, and those at risk for complications. This drug may be prescribed prior to an official diagnosis with a test if the virus is suspected. Based on these guidelines, Tamiflu should not be prescribed for healthy patients. It is not recommended to prescribe this medication at clinics for patients who need a shortened symptom period from the flu in order to return to work or to avoid the uncomfortable symptoms. The guidelines are clear and indeed the public does put pressure on prescribers that is very much the same as the demand for antibiotics. Society today demands a quick fix to getting ill and perhaps this is due to pressures of having to miss work but worldwide the best medicine for illness is rest. We are living in such a stressed and high paced society that rest has become a forgotten treatment. Are practitioners prescribing Tamiflu as mainstream now and is this influencing the epidemiology of the flu viruses?

The side effects or rare complications of Tamiflu include nausea and vomiting and severe but rare neuropsychiatric events. The antiviral is only 70-90% effective. The CDC has very thorough and specific prescribing guidelines for practitioners and with the end result to protect the public.

Connie Lapadat, NP, is a family nurse practitioner in El Cajon, CA. She is a 2018–19 Doximity Author.


  1. CDC. (Dec 2018). Influenza Antiviral Medications Summary for Clinicians. Retrieved from

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