Guidance

Chief Medical Officer and Chief Pharmaceutical Officer: advice on using antiviral medicines: influenza season 2015 to 2016

Updated 8 January 2016

1. Influenza season 2015 to 2016: use of antiviral medicines

Professor Dame Sally Davies, Chief Medical Officer and Dr Keith Ridge, Chief Pharmaceutical Officer at NHS England, provide advice for healthcare professionals on the use of of antiviral medicines.

The most recent surveillance data indicate that there has been a recent increase in influenza virus activity and that there is now a substantial likelihood that people presenting with an influenza-like illness are infected with an influenza virus.

GPs and other prescribers working in primary care may now prescribe at NHS expense, antiviral medicines for the prophylaxis and treatment of influenza, in accordance with National Institute for Health and Care Excellence (NICE) guidance and Schedule 2 to the National Health Service (General Medical Services Contracts) (Prescription of drugs etc) Regulations 2004), commonly known as the Grey List or Selected List Scheme (SLS).

You should consider prescribing antiviral medicines for patients if they are at risk of severe illness and/or complications from influenza if not treated, whether or not they are in a ‘clinical at risk group’. The use of antiviral medicines is supported by the NICE. Their guidance on the use of antiviral medicines can be accessed for treatment and for prophylaxis.

There is good evidence that antiviral medicines can be of benefit and that they reduce the risk of death in patients hospitalized with influenza. A recent widely reported Cochrane review of trials of influenza antivirals found only a small, but significant, clinical benefit in patients with mild illness in the community. There is evidence, however, from an observational study that early treatment of hospitalised patients with influenza can reduce mortality ^{[footnote 1]}. More recently, a report from the Academy of Medical Sciences and Wellcome Trust on the use of neuraminidase inhibitors (NAIs) in influenza, supported the use of antiviral medicines in patients who are severely ill with influenza, and that the routine use of antivirals for patients with influenza may be advisable when influenza circulates more widely or causes more severe symptoms.

1.1 The Grey List

The ‘Grey List’, which is included within the Drug Tariff at Part XVIIIB, restricts prescribers working under a primary care contract to only prescribe antiviral medicines to specified people who are listed in the Drug Tariff. i.e. the clinical at risk groups, pregnant women, people over the age of 65 years and those people under 65 years of age who are not in `clinical at risk’ groups but are clinically assessed to be at risk of developing medical complications from influenza.

Clinicians in secondary care are not subject to the ‘Grey List’ restrictions that apply in primary care to prescribing of antiviral medicines, They can therefore use their clinical judgment to prescribe antiviral medicines, including for those not in the ‘clinical at risk’ groups.

For clinicians treating hospitalised patients with suspected influenza, rapid laboratory confirmation with subtype identification is advised, to support patient management.

1.2 Advice for prescribers for endorsing prescriptions

Further information on the at-risk groups and patients who are eligible for treatment in primary care at NHS expense with either oseltamivir (Tamiflu) or zanamivir (Relenza) can be found in Part XVIIIB of the Drug Tariff(Drugs, Medicines and Other Substances that may be ordered only in certain circumstances.

Primary care prescribers are reminded to endorse all prescriptions for oseltamivir (Tamiflu) and zanamivir (Relenza), with the reference ‘SLS’. Community pharmacies are only able to dispense oseltamivir and zanamivir at NHS expense, if the prescriber endorses the prescription with ‘SLS’.

1.3 Prescribing for children over the age of one year

Wherever possible, for children over the age of one year and for adults who are not able to swallow capsules, the appropriate strength of capsules should be prescribed. The contents of the capsules can be emptied and added to a suitable sugary diluent. As far as possible, oseltamivir (Tamiflu) suspension should be restricted for children under one year of age. This will support the continuity of supply of the liquid form of oseltamivir for this vulnerable age group.

1.4 Prescribing for children under one year of age

Oseltamivir (Tamiflu) is not licensed for use in children under one year of age for seasonal influenza. Prescribing of oseltamivir for this age group for seasonal influenza, should be based on the judgment of the clinician, after considering the risks and benefits of treatment.

1.5 Liaison with manufacturers and wholesalers

The Department of Health is in contact with manufacturers to ensure that there are adequate quantities of antiviral medicines in the supply chain.

We would urge pharmacies not to over order stocks of antiviral medicines. Over ordering could result in shortages in the supply chain. It is, however, important that oseltamivir for adults and children and zanamivir for adults are taken within 48 hours of onset of symptoms. Children 5 years and over and under 13 years of age should start taking zanamivir within 36 hours of onset of symptoms, to obtain maximum benefit.

2. Maximising uptake of flu vaccination, including healthcare staff

The increase in flu activity also highlights the need to ensure maximum protection through vaccination. Please encourage as many people in the at risk qualifying groups those aged 65 and over, those under 65 in ‘at risk’ groups, pregnant women and children aged 2 to 4 and in primary school year 1 and year 2 to get the flu vaccination.

It is also important that frontline healthcare workers, including GPs, nurses, pharmacists, and their teams, minimise the risk of transmitting flu by getting vaccinated themselves and observing strict infection control measures. This season 44.1% of healthcare workers have been vaccinated up to end of November 2015, please vaccinate yourself as this will help protect those in your care, as well as you and your family.

1. Muthuri et al, Lancet Respir Med 2014;2:395-404 ↩