Flu is an extremely debilitating viral infection which can prove particularly serious for the over-65s, and for this reason, pensioners are now offered a free course of vaccination at the approach of winter every year.

That said, flu viruses mutate almost continuously, so it is unlikely that having the jab will prove effective in protecting you against the most prevalent strain in any one year or indeed, prepare you for the mortifying shock of seeing the enormous size of the hypodermic apparatus now routinely used to administer it.

Despite these practical and psychological drawbacks, most medical practitioners still recommend vaccination, if only to provide some measure of protection against extant forms of flu such as Imelda flu, named after the former first lady of the Philippines and normally passed on through shoes; Demelza flu, which turns the hair red and may induce whispering gibberish in an unidentifiable accent; and Chiminee flu, which can cause sooty deposits in the lungs and, in some cases, lead to magpies or seagulls nesting in the hair.

It’s long been thought that a strain of flu resistant to all forms of treatment will inevitably emerge and the NHS has already established a network of Viral Doomsday (VD) clinics to deal with this eventuality.  Unfortunately, this hastily conceived clinical nomenclature has created a degree of confusion among the population at large and many now believe that flu is a sexually transmitted disease.

This is not the case, unless you have intimate relationships with swine, avians or people of Spanish or Asian ethnicity.