Let students take turns acting the parts of the solar system. Even all-weather tires give up some snow and ice performance in order to run well year-round. For real winter driving, a set of snow tires are always best.One question I get asked a lot; “Can't I just put two.There are three major considerations to keep in mind when contemplating whether to put only two snow tires on your car:Trust me, tire dealers do not insist on four snow tires just so they can sell you two more tires –,So you've decided that you need the optimal grip and handling of dedicated snow tires. But the NHS says anyone aged 50-64, and in an at-risk group, should "not delay" having the flu vaccine.Doctors also want to increase vaccination levels in the most deprived areas and among people from ethnic minorities.Many pharmacies will also offer the jab privately for about £20, although Boots has temporarily suspended bookings for anyone under the age of 65, to ensure its existing stock is prioritised for those at highest risk.Flu - or influenza - is a very common, highly infectious disease, caused by a virus.It can be deadly - particularly for older adults, very young children and people with underlying health conditions.The average number of estimated deaths in England for the past five annual flu seasons is more than 11,000 - but there have been big variations each winter.There were more than 22,000 estimated deaths in the 2017-18 season, but just short of 4,000 deaths in 2018-19.There's some evidence that a double infection - of Covid-19 and flu together - could be more deadly than getting either single virus.But there's also a school of thought - yet to be proven in the case of coronavirus and flu - that having one virus could potentially help prevent a second from entering the body at the same time.What is clear is that a big flu season combined with coronavirus could overwhelm hospitals - especially if lots of NHS or care-home staff are off sick with flu.The worry is that certain groups of people - the elderly, pregnant women and those with long-term health conditions - are at high risk of becoming seriously ill from both coronavirus and flu.And while many healthy people can fight off the flu, there can be complications - most commonly a bacterial chest infection, which can develop into pneumonia.Other potential life-threatening complications include meningitis and septic shock.Some countries in the southern hemisphere including South Africa and Australia - both nearing the end of their flu seasons - have reported lower levels of the illness than expected.This could be partly because coronavirus lockdown measures - social distancing, masks and extra hand-washing - have also helped reduced the spread of flu.But doctors say there's no guarantee the UK flu season will follow the same trend, particularly as lockdowns ease, and are urging people to be vaccinated.The World Health Organization (WHO) also warns of caution when interpreting trends.In some countries, for example, reduced staffing levels during the Covid-19 pandemic could mean flu cases are not recorded in the same way as before.Many of the symptoms are similar for both viruses:Some people may also experience muscle aches, a headache, and possibly diarrhoea or vomiting.And if you add in other common winter viruses it can be hard to be sure what is making someone ill.Remember, both flu and coronavirus can also be spread before people have any symptoms - or by people who don't get symptoms at all.Because of the pandemic, health staff are being urged to:Pregnant women may be offered jabs during antenatal appointments.The Department of Health and Social Care says it has ordered additional quantities of the adult vaccine to ensure demand does not outstrip supply.Every year, the WHO looks at the current circulating flu strains before recommending what the next set of vaccines should contain.But because the vaccines often have to be made six months in advance, they can only ever be a prediction.Experts say it's better to be vaccinated against some strains of flu than none at all - particularly during a pandemic.The US is the worst hit country in the world and cases are still continuing to rise, data shows.What happens to your body in extreme heat?Social distancing may influence the spread of the flu this year,New measures may be put in place while people have their vaccinations.Coronavirus: How bad will winter really be?Most people in England to be offered flu vaccine.Covid symptoms: Is it a cold, flu or coronavirus?What's the UK's plan and what could happen next?Read about our approach to external linking.Consider asking people to wait in their cars until called,Arrange home visits for the most vulnerable. It’s important for us to know how we feel, but it’s more important to know why we feel the way we do. When the south pole is tilted away from the sun, it is summer!The in-between seasons (spring and fall) are when the earth gets just about the same amount of sunlight on the south and north poles.