In a bid to make the most effective use of Tamiflu and Relenza and stop people hoarding and overusing them like some did when swine flu first broke out earlier this year, the US Centers for Disease Control and Prevention (CDC) said yesterday that most people will not need drugs if they get the flu this season and neither should they expect to have them.

Dr Anne Schuchat, director of the CDC’s National Center for Immunization and Respiratory Diseases said on Tuesday that “the majority of adolescents and adults and most children won’t need antiviral treatment”, according to a report in the Wall Street Journal.

However, there were certain groups that were at higher risk, and in these cases doctors should not wait for tests to confirm 2009 A H1N1 swine flu before prescribing antivirals because patients need to start taking them within 48 hours of onset of symptoms.

Schuchat said that time window of the first two days is very important. The press briefing coincided with the release of new CDC guidelines on the use of antivirals for treating and preventing spread of flu, including the new 2009 H1N1 swine flu as well as seasonal flu.

The purpose of the new interim guidelines is to help health professionals prioritize use of antivirals for patients at higher risk of flu-related complications.

The CDC said it would be revising the guidelines as they learn more about the 2009 H1N1 flu and they should also be used in the context of local scientific knowledge about swine flu, antiviral susceptibility patterns, and antiviral supply consideration.

The guidelines have general recommendations and also specific recommendations for particular patient groups. Among the general recommendations are suggestions that:

  • Anyone with suspected or confirmed influenza that requires them to go into hospital should be treated with oseltamivir (Tamiflu) or zanamivir (Relenza).
  • In general, anyone with suspected or confirmed influenza who is at higher risk for complications should be treated with oseltamivir (Tamiflu) or zanamivir (Relenza). These include children under 5, adults 65 and over, pregnant women, people with chronic conditions, people with weak immune systems, and people under 19 who are on long term aspirin treatment.
  • Anyone who is not at higher risk for complications or whose influenza does not require them to be treated in hospital generally does not need antivirals.
  • However, anyone with suspected or confirmed flu who shows warning symptoms or signs of lower respiratory tract illness should promptly be given empiric antiviral therapy. The warning symptoms and signs include shortness of breath (dyspnea), rapid breathing (tachypnea), and unexplained oxygen desaturation.
  • Groups at higher risk for 2009 H1N1 influenza complications are similar to those at higher risk for complications from seasonal influenza.
  • To minimize delays in starting treatment, people at higher risk of complications should be (1) informed about how to spot early signs and symptoms of flu (eg fever, respiratory symptoms), (2) given easy and quick telephone access to a doctor for a clinical evaluation (as well as anyone who reports serious illness), and (3) be considered for empiric treatment based only telephone contact if it substantially reduces delay to treatment and if hospitalization is not indicated.
  • In certain particular cases, doctors may choose to provide patients in higher risk groups (eg with neuromuscular disease) with prescriptions that can be filled following a telephone call at the start of symptoms.

The guidelines also emphasize that, as always, clinical judgement is an important part of the decision of whether to give antivirals to patients who have illnesses consistent with influenza.

The CDC also said it was generally acceptable for doctors not to prescribe antivirals to high risk patients who don’t have the flu but have been exposed to it, and only prescribe antivirals if they develop symptoms.

— more info on CDC’s updated interim recommendations.

Sources: CDC, Wall Street Journal.

Written by: Catharine Paddock, PhD