The flu season is just around the corner and, with cases of the virus already starting to appear, now is the best time to get yourself protected.
Flu is a nasty and potentially dangerous infection and its impact is often underestimated. Public Health England (PHE) says around 15,000 people died from flu-related causes in the UK last year, including complications such as pneumonia arising from an initial flu infection.
Most - although not all - of those who become seriously ill are in at-risk groups which are offered free vaccinations on the NHS. And while the peak flu season doesn't usually begin until December, now is the best time to get vaccinated, as it takes between 10-14 days for the immune system to respond fully afterwards. The NHS says that, while the optimum time to have a flu vaccine is from the beginning of October to the end of November, if you have the vaccine later, it will still offer some protection.
And, contrary to some media reports, the NHS insists there's no shortage of the vaccine, while supplier Seqirus says any remaining phased vaccine deliveries to GPs and pharmacies will have been completed by the end of this week.
The at-risk groups offered free vaccinations are adults aged 65 and over, people with long-term health conditions such as diabetes, asthma or heart disease and children in at-risk groups from six months of age, pregnant women, children aged two to nine years old, and carers of elderly and disabled people. They also include anyone living in a long-stay residential care home or other long-stay care facility.
Each year, the viruses most likely to cause flu are identified and the World Health Organisation (WHO) recommends which type of strains to include in the vaccine. This season there are three types of flu vaccine available, depending on your age and risk level.
PHE head of flu Dr Richard Pebody says: "Flu can be extremely serious and can kill the most vulnerable. Vaccination is by far the best defence we have. Anyone at increased risk from the effects of flu is offered the vaccine for free - speak to a GP or pharmacist, or look out for an invitation from your child's school, to get yourself or your loved ones protected this winter.
"To help prevent the spread of flu, practice good hand hygiene. Catch coughs and sneezes in a tissue, throw the tissue away and wash your hands."
And here are 10 things you should know about flu:
1. When someone with flu coughs or sneezes, expelled droplets can infect people up to 6ft away.
2. In the UK, the annual flu season runs from about October to March or April, although most cases occur between December and February.
3. Flu leads to hundreds of thousands of GP visits and tens of thousands of hospital stays a year. But, if you're otherwise healthy, the virus will usually clear up on its own within a week.
4. The flu virus is extremely variable and changes over time. Each year there are different strains around and a new vaccine has to be prepared to deal with them. Vaccination from previous years isn't likely to protect people against current strains of flu.
5. Oxford University's Vaccine Knowledge Project says there are three basic types of flu: A, B and C. Type A is the most dangerous and can cause serious disease and trigger worldwide pandemics. Type B can make you feel very ill, but has never led to a pandemic, and Type C causes mild disease.
6. Typically, effectiveness of the flu vaccine is in the range of 30-60% and the NHS stresses that having a flu vaccination won't stop all flu viruses. The level of protection may vary, so it's not a 100% guarantee that you'll be flu-free. However, if you do get flu after vaccination, it's likely to be milder and shorter-lived than it would otherwise have been.
7. Side-effects of the nasal vaccine may include a runny or blocked nose, headache, tiredness and loss of appetite. The injected vaccine may have side-effects including a sore arm at the site of the injection, a low-grade fever and aching muscles for a day or two after the vaccination. Serious side-effects with either the nasal spray or jab are extremely rare.
8. Last year, only 68.7% of front line NHS staff took up the free flu vaccination. This autumn, NHS Employers has rolled out its Flu Fighter campaign for the third consecutive year, aiming to encourage more health workers to have the jab.
9. The European Commission estimates more deaths are caused by flu than by car accidents across the continent each year. Yet, around 100 million people recommended for the flu jab annually don't take it up despite recommendations from the World Health Organisation.
10. Research from the Universities of Lincoln and Nottingham suggests the flu vaccine can reduce the risk of having a stroke by about a quarter.