Colds and flu may seem trivial, but for some they can be incapacitating or even life-threatening. The terms cover a group of respiratory illnesses caused by three influenza viruses and more than 200 common-cold viruses. They are more prevalent in the winter because we huddle close to people who are harbouring the viruses, and because cold air affects the nose’s ability to fight infection. Here is everything you need to know to stay healthy this winter ...

My boss said that if I can stand up, it’s not flu. Is this true?

Your boss may not be objective or, indeed, correct. But the general point is that flu comes on more suddenly, feels worse and lasts longer than a cold. It causes a sudden high temperature, shivering, deep tiredness, weakness and aching muscles. Other symptoms are similar to those of a cold, such as a sore throat, a dry cough and a runny nose. Kids can experience stomach aches, diarrhoea and vomiting.

I get that flu is nasty, but it passes. Why all the fuss?

There are three types of flu: type A is the most dangerous and can cause worldwide outbreaks (pandemics); type B makes people feel ill; and type C is relatively mild. On average, flu kills 600 people a year in the UK; in bad years, that figure can rise to thousands. Most people make a full recovery, but serious complications, such as pneumonia, can affect anyone, especially babies, pregnant women, those with long-term medical problems and older people whose immune systems are impaired.

Should I get a flu jab?

There are a few ways to avoid flu: stay away from other people; wage war against flu spreaders who leave their snotty tissues lying around; or get a jab. Two vaccines are available in the UK. The nasal flu vaccine is being rolled out gradually to all children over the age of two, while the inactivated flu vaccine is offered on the NHS to vulnerable adults (over-65s, pregnant women, those with serious medical conditions such as asthma, plus care-home residents, carers and healthcare professionals). If you are not in a vulnerable group, you can get the jab privately – many pharmacists and workplaces offer it for a small charge. Babies under six months old are too young to be vaccinated against flu, but pregnant women are encouraged to have the jab to protect themselves and their newborn babies. Children are vaccinated partly to protect them, but also because they are walking virus reservoirs – they remain infectious for two weeks longer than adults and are more likely to pass on the virus.

Can I get flu from the jab?

No. It contains inactivated virus, so you may feel a bit shivery and your arm may ache, but it’s nothing that a couple of paracetamol won’t sort out. Allergic reactions are rare, but potentially dangerous. There was a small rise in reported cases of the neurological condition Guillain-Barré syndrome (GBS) among people who had a swine flu vaccine in 1976, but it’s not clear why. If there is an increased risk of GBS after flu vaccines, the chance is still only about one in a million.

Is swine flu still a thing?

Swine flu – so-called because pigs get a similar virus – was a relatively new strain of flu that caused a pandemic in 2009-10. It has been around for a while now, so lots of people have immunity and it’s part of the annual flu vaccine. It caused far fewer serious cases than expected, since many older people had been exposed to the strain in their youth and had retained some immunity.

What about Tamiflu?

The antiviral drugs oseltamivir (Tamiflu) and zanamivir (Relenza) were doled out by the bucketload during the swine flu scare. Questions remain about their effectiveness. Professor Stuart Pocock of the London School of Hygiene and Tropical Medicine, a co-author of an extensive analysis of the evidence, says: “There is some shortening of duration of flu symptoms (by about 24 hours) and a reduction in the risk of lower respiratory complications. This needs to be set against an increased risk of nausea and vomiting.” The drugs don’t prevent flu, but can mitigate its severity once you develop it. A report by the Academy of Medical Sciences and the Wellcome Trust in October 2015 said that pregnant women who are hospitalised with flu should be given the treatment and that clinicians should weigh up the pros and cons of treating children and those in high-risk groups. If a particularly virulent strain of flu comes along, offering antivirals widely may be justified. Until then, it isn’t.

Is it true that the nasal spray for children doesn’t work?

Recent US data showed that the nasal flu vaccine wasn’t very effective from 2013-16 overall and seemed to give little or no added protection in the winter of 2015 in children aged 2 to 17. In the UK, the Joint Committee on Vaccination and Immunisation has reviewed the evidence from the UK, the US, Finland and Canada; it says there is evidence of good overall effectiveness and that children should continue to use the nasal spray.

Why didn’t the flu vaccine work for me last year?

Some years it will be more effective than others. Partly, it depends on you. One year, you may be in rude health and not mix much with ill people; another, you may be run down and unlucky. Another factor is the vaccine: every year, 143 national flu centres in 113 countries monitor current and emerging strains of flu virus and test existing vaccines on them. The results are passed on to six World Health Organisation centres (two in the US and one each in the UK, Australia, Japan and China), which meet to recommend the composition of the vaccine for the northern and southern hemispheres. It’s a good system, but sometimes the experts are flummoxed by a rogue strain.

I’ll be all right – I take echinacea and vitamin C all winter

Hopefully, you will be fine, but it may not be due to the products you are taking. Echinacea is enthusiastically marketed to prevent and treat colds – the US market alone is worth more than $28m – but the evidence shows a modest benefit at best and certainly doesn’t justify the commercial claims. High-dose vitamin C (1,000-2,000mg/day), garlic, exercise and homeopathy don’t prevent colds, either. In fact, pregnant women and people with impaired kidney function are advised to avoid vitamin C supplements; a normal, balanced diet provides plenty of vitamin C.

What can I take for my cold?

Professor Bruce Arroll of the University of Auckland says: “There is no effective treatment for the common cold, but there are treatments that can help with the symptoms. The evidence is not great for anything except ipratropium nasal spray (Rinatec). There is no role for antibiotics for the cold or respiratory symptoms (when there is no diagnosis of pneumonia or emphysema).”

Many studies are poorly designed, conflicting or inconclusive, but it seems that honey may help a cough. Nasal saline and humidified air may be helpful for sleep and are unlikely to cause any harm. Chinese medicinal herbs, ginseng, echinacea and vitamin C don’t appear to offer any benefit. Ibuprofen helps aches and pains and reduces fever more effectively than paracetamol, especially in children. There is no benefit in taking paracetamol and ibuprofen together, despite the fact they are often sold in combination. Arroll adds: “Nasal and oral decongestants are probably effective and worth trying if [you are] very congested. Vicks is also worth trying, based on one study.”

My partner has a stinking cold. Should I decamp to the couch?

Cold viruses are not as infectious as you might think. An infected person can spread their virus by coughing or sneezing close to you or touching a door handle with their virus-infested hands. But you can kiss and have sex with your infected partner without running a high risk of catching the virus, although why you would want to beats me.