Influenza, more commonly known as ‘the flu’ is an infectious disease caused by viruses. It affects birds and mammals with a range of symptoms including fever, chills, sore throat, aching muscles, headache, coughing, and general discomfort although up to 30% of people show no symptoms.
Influenza is a more severe disease than the common cold and is caused by a different type of virus. There are three types of flu virus: A, B and C, with A and B responsible for most clinical illness. Following infection, flu has a usual incubation period of one to three days. For an otherwise healthy person, flu is a self-limiting disease with recovery usually within two to seven days.
Influenza is most commonly spread by the airborne route (when someone inhales air contaminated by an infected person coughing, sneezing or spitting) or via hand-to-eye, hand-to-nose, or hand-to-mouth touching after the hand has touched a contaminated surfaces (including direct personal contact such as a hand-shake). A single sneeze can generate tens of thousands of infected droplets whose survival rate in air is enhanced by low humidity and a lack of sunlight in winter. Both these routes – as well as direct transmission – contribute to the spread of the virus, and indicate the importance of common sense and personal hygiene to limit transmission.
Most cases of flu in the UK tend to occur during an eight to ten week period during the winter. The timing, extent and severity of this ‘seasonal’ flu can all vary and are unpredictable. Flu A is the predominant virus causing outbreaks most years and is usually the cause of epidemics. Large epidemics occur intermittently. Flu B tends to
cause less severe disease, although in children the severity of the illness may be similar to that associated with flu A.
The UK National Health Service has a flu vaccination programme each year. This is available for high-risk groups such as those over the age of 65. A seasonal flu shot provides the best protection even when the vaccine does not exactly match the circulating flu strains, and even when the person getting the vaccine has a weakened immune system. Even when it does not provide protection from infection, the vaccination can lessen severity of the disease. The NHS web site can provide updated details on the Winter 2012/13 program.
People with flu are advised to rest, drink plenty of liquids, avoid alcohol, and take ibuprofen or paracetamol for fever and muscle ache. Antiviral medicines prevent the virus from replicating inside the body. They can lessen symptoms by a couple of days and reduce their severity, and help to reduce the likelihood of complications.
Antiviral medicines are available from Express MD.
Antiviral medicines are typically available on the NHS in the UK for certain groups of patients only, including those in the identified at-risk categories. However, patients who are not in one of the identified clinical risk groups can be prescribed these medications if the Chief Medical officer (CMO) has distributed a letter to prescribers informing them that they are now able to prescribe antiviral medicines to a wider group at their discretion. Usually, these would be patients who they consider may be at risk of developing serious complications from flu and could benefit from receiving the treatment.
Antiviral drugs Tamiflu (oseltamivir) and Relenza (zanamivir) have been used successfully against both influenza A and B.