The weekly U.S Influenza surveillance report published in the Centers for Disease Control and Prevention shows the influenza activity has continued to remain low in the country for the current influenza season. However, the active virus circulating is identified as influenza A(H1N1)pdm09 reported in the recent three weeks. In the United States, Guam and two States shows local influenza activity, forty states with sporadic activity and one influenza-related pediatric death has so far been reported. According to the WHO, the second most common illness globally is influenza and is the third cause of death. And hence, CDC recommends appropriate measures that need to be taken to prevent the infection and to effectively treat it with antivirals to stop the complications that can develop particularly among the high risk group of people. Here we discuss the actions and recommendations by CDC for the initiation of antiviral treatment, its duration or chemoprophylaxis and vaccine recommendations for the season 2017-2018.

Antiviral Treatment Recommendations

For the treatment of influenza, there are five licensed prescription antiviral drugs in the United States. The three antiviral drugs approved by the FDA are known as neuraminidase inhibitors and are available as treatment options for the influenza season 2017-2018. The neuraminidase inhibitors are oral oseltamivir, inhaled zanamivir and intravenous peramivir. Antiviral drugs belonging to the class of medications called adamantanes are amantadine and rimatadine which are only active against influenza A. Due to the high levels of resistance, adamantanes are not recommended for the treatment of influenza.

According to the CDC, the antiviral treatment should be initiated;

  • As early as possible in the case of an either confirmed or suspected cases of influenza infection particularly for hospitalized patients or presenting severe progression of the illness
  • For individuals younger than 2 years and older than 65 years of age
  • Within 48hours of illness onset for uncomplicated symptomatic outpatient
  • Without the need for waiting for diagnostic results particularly among the high risk groups such as pregnant women
  • Patients with health problems such as asthma, metabolic disorders, cardiovascular disease, neurodevelopmental conditions, kidney or liver disorders

Treatment Duration or Chemoprophylaxis

Treatment: It is recommended for duration of 5 days for oral oseltamivir and inhaled zanamivir although longer duration is recommended for severely ill patients. In the case of an uncomplicated influenza, a single dose of intravenous peramivir is sufficient. The currently preferred oral oseltamivir should be used for pregnant women or women up to two weeks postpartum.

Chemo prophylaxis: after the last known exposure, the recommended duration is 7 days although in the case of outbreaks in institutional settings, antiviral chemoprophylaxis is recommended for a minimum of 2 weeks.

Influenza Vaccines Recommendations for 2018-2019

According to the CDC’s recommendation, individuals should get vaccinated by the end of October. As the influenza viruses are constantly changing, the composition of the vaccines are reviewed and updated to effectively target the circulating viruses for the season.  The three component vaccines contain; A/Michigan/45/2015 (H1N1)pdm09-like virus, A/Singapore/INFIMH-16-0019/2016 A(H3N2)- like virus (updated) and N/Colorado/06/2017-like (Victoria lineage) virus (updated). The options of vaccine shots for this season include the standard dose flu shots, high-dose shots, shots made with adjuvant, live attenuated influenza vaccine (LAIV) and shots made with virus grown in cell culture. CDC and its vaccines advisory committee (ACIP) recommends that the health care providers use the age-appropriate influenza vaccine with no preference expressed for one vaccine over another.

  • Standard dose flu shots

For the influenza season of 2017-2019, CDC recommends the use of vaccine such as inactivated influenza (IIV), recombinant influenza vaccine (RIV) or live attenuated influenza vaccine (LAIV). The trivalent influenza vaccines includes standard-dose trivalent flu shot (IIV3) , a high-dose trivalent flu shot, a trivalent flu shot made with adjuvant and a recombinant vaccine. The standard quadrivalent vaccines include the standard-dose, a quadrivalent cell-based flu shot and a recombinant quadrivalent flu shot.

  • High dose shots

Fluzone High-Dose is a trivalent inactivated vaccine to be administered for people over the age of 65 that contains antigen four times more than the standard inactivated vaccine to provide better immune response. A study published in the New England Journal of Medicine shows that this high dose shots are 24.2% more effective than the standard dose.

  • Shots made with Adjuvant

This is a standard-dose, trivalent inactivated vaccine that has an adjuvant and is only licensed for people older than 65 years of age but not recommended for those with a history of severe allergic reaction to the flu shot or to the components other than the eggs.

  • Shots made with virus grown in cell culture

A cell-based vaccine that is developed in cultured cells of mammalian origin as an alternative to the egg-based process of developing the shots. This is more effective giving better protection than the egg-based vaccines because of its similarity to the flu viruses.

  • Live attenuated Influenza vaccine (LAIV)

All the nasal flu vaccines has four flu viruses: an influenza A(H1N1) virus, an influenza A (H3N2) virus and two influenza B viruses. LAIV is recommended for non-pregnant people from the age of 2 to 49 years of age. It is not recommended for those with a weakened immune system, an asthmatic condition and with other medical conditions who can develop serious flu related complications.

  • Recombinant Flu Vaccine

This is an egg-free vaccine and the Flublok quadrivalent recombinant vaccine that is licensed for use among people over the age of 18. This vaccine has shorter shelf life than the other influenza vaccines.

Initiating a Strong Influenza Vaccine Recommendation

The use of SHARE is recommended by the CDC so the health care professionals can help ensure the public receive their vaccines by identifying their concerns and addressing it. This can be achieved when the health care professionals;

  • SHARE the information with the patient as to the need of receiving the vaccine given their age, lifestyle habits and other risk factors
  • HIGHLIGHT positive experience so the patients can benefit from it and to strengthen confidence in influenza vaccination
  • ADDRESS patient questions by providing information about the effectiveness, side-effects and safety of the vaccines in a plain language
  • REMIND the patients how the vaccine can protect them and their family from influenza associated complications
  • EXPLAIN the cost of getting influenza such as the financial burden, other obligations missed and serious health effects

References

  1. https://www.cdc.gov/flu/about/season/flu-season-2018-2019.htm
  2. https://www.cdc.gov/flu/professionals/vaccination/flu-vaccine-recommendation.htm
  3. https://www.cdc.gov/flu/professionals/antivirals/avrec_ob.htm
  4. https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm