Winter is coming: How worried should we be about coronavirus?

Between 5 March, when the UK had its first coronavirus-related death, and 31 July, the nation reached an official death toll of 45,999. This is much higher than estimates given in March by both an Imperial College study, which predicted 5,700 deaths, and by health chief Stephen Powis who said keeping the deaths below 20,000 would be a “good result”.

Despite the high numbers lockdown restrictions have gradually been eased. But on Friday, Boris Johnson warned that infection rates across England are slowly beginning to creep up. The prime minister described the situation as “the warning light on the dashboard” and said that it was necessary to reverse some planned measures. Chris Witty, the government’s chief medical adviser said at the same press conference, the UK was reaching “the limit of what we can do”.

These foreboding statements come just 24 hours after Mr Johnson warned that our European neighbours are beginning to experience signs of the much-dreaded “second wave”. On 28 July the prime minister said the UK must remain “vigilant” to such a threat – against a background of reports that he was “extremely concerned” a similar fate awaits the UK in two weeks’ time.

In spite of this, many do want to continue easing restrictions – not least because the economy needs people outside of their houses – but also because, as Mr Witty said on 31 July, there could be “big disadvantages” to waiting later in the year, until the winter, to start reopening.

The UK is still relying heavily on summer-compatible mitigation measures, such as encouraging socialising outside (in gardens or parks), queueing outside shops to reduce capacity, or visiting outside theatres, drive-in cinemas and concerts. In addition seasonal illnesses, like flu, are less prevalent in the summer months, giving more capacity for the NHS to deal with Covid-19, unlike in winter when it is historically overrun.

So as Mr Johnson is forced to “put on the brakes” on lockdown measures – on the hottest day of the year so far – how do our prospects look for the winter? Is it reasonable to expect, as Boris Johnson promised, that we will have a “more significant return to normality” by Christmas?

Will coronavirus be more dangerous in the winter?

On 14 July a report, requested by chief scientific adviser, Sir Patrick Vallance, found the UK could see 120,000 new Covid-deaths in a second wave of infections throughout winter. This was a model for a “reasonable” worst-case scenario, which they estimated would peak in January and February. Sir Jeremy Farrar, a member of the government’s Scientific Advisory Group for Emergencies (Sage), also warned there could be a “very nasty rebound”.

But why is this the case? Is it because Covid-19 will be more prevalent in the winter months? Early on in the pandemic reports suggested Covid could get worse as the weather turns colder, but this was largely because much of the early coronavirus modelling was based on the flu (both scientists and advisors were closely following a well-laid plan for flu, which explains why a policy of herd immunity was floated), which does get worse in winter.

As time has passed, it is apparent that Covid-19 does not operate in the same way as the flu, which is known to boom between December and March (flu particles love dry cold air which help them break up and spread further, and do not travel so well in moist hot air).

Robert Dingwall, professor of sociology at Nottingham Trent University and on the Department of Health’s Nervtag (New and Emerging Respiratory Virus Threats Group), tells The Independent: “There is an assumption that Covid will behave like influenza but no evidence to show that. At the moment there doesn’t seem to be a seasonal impact – Australia has had Covid-19 in both summer months and winter months now.”

Micheal Head, senior research fellow in global health at the University of Southampton, agrees that cases elsewhere in the world suggest the winter won’t make things worse just because it is cold. “The increasing numbers of cases across hotter countries in the tropics suggest that sunshine and humidity are probably not a big factor in terms of the transmission.”

This also would explain why the summer hasn’t seen decreased cases, as was initially hoped it might, says Dr Simon Clarke, associate professor in cellular microbiology at University of Reading. “In February lots of people were saying summer will get rid of it, the sunlight the heat, and I can understand why people say that but it’s not cold in Brazil and they’ve had a horrid time of it, it’s not cold in Florida or California in the USA either [both have high numbers of cases].”

If the virus behaves the same all year – can we expect the same rates as now?

Even if the weather has no bearing on the spread of the virus – there are other contextual factors to consider that might make coronavirus harder to deal with as we enter the winter. For example, changes in human behaviour or competing pressures on the NHS.

Dr Clarke says there is a possibility that people might be more inclined to take risks and see people indoors because of the weather: “You might sit in the garden with your friends at this time of year, you’re not going to be doing that in December, you are not going to want to sit in the park in January – not for very long anyway. The winter doesn’t afford the opportunity to be outside quite so much.”

Dr Jenna Macciochi, lecturer in immunology at the University of Sussex, agrees that the key concern will not be the temperature impact on the virus but this temperature impact on human behaviour. “Social distancing will be harder, this is definitely a concern, we know that social distancing in addition to other measures is super important in preventing spread. Being outside is also preferable to indoors and having nice weather makes this easier.”

Although Dr Dingwall says whether or not this is a problem will largely depend on ventilation in any given space. “I think maybe this is less of a problem than some people are making out – the extent of ventilation indoors will be the same as it is now, and it will still depend on people being infectious and in close proximity.”

What about other factors?

Even if the virus does not get worse in winter, and people continue to abide my lockdown rules – one non-negotiable difference is the strain on the NHS of competing pressures at that time of year. Frequently the NHS suffers a “winter crisis” that sees long waits in A&E and lack of bed space. This year the NHS will be dealing with the usual caseload as well as a backlog of regular non-coronavirus work that has been pushed back during the pandemic.

Head says: “Health services are typically more stretched during the winter months. This makes it even more important that we suppress cases now, and keep them as low as possible.” Dr Clarke is more specific and says the reason the NHS is “put under strain” at that time in the year is because of other respiratory tract viruses that occur in the winter months. “Flu is a concern – some years we have quite a mild flu and some years we don’t.”

The government has already put into place an extensive flu programme for this winter – with more people eligible than ever. Health Secretary Matt Hancock said the government had procured enough vaccine to roll out the “biggest programme in history” – for anyone over the age of 50 and children aged up to secondary school (as well as people who are normally eligible). It is hoped the uptake will be huge.

But Dr Clarke warns that the vaccine isn’t always successful – as much of it relies on guess work to identify the correct strains for that year. “There have been examples where they got the wrong strains, or they got the right strains but the vaccine doesn’t work terribly,” he cautions.

Dr Dingwall says even if the vaccine wasn’t a success we may not necessarily have to worry about flu season, precisely because Covid-19 is still hanging around. “There are weird dynamics between respiratory viruses – they seem to kind of crowd each other out. So if one is prevalent at high levels, others tend not to get a look in. Nobody quite understands this phenomenon but it has been noticed in competition between influenza and others in the past.”

He says there is already some indication from Australia that this might be the case – Dr Clarke also says that the social distancing measures and increased hand washing might just be stopping people from contracting flu in the first place, when they normally might.

Can we expect to be “back to normality” by Christmas?

Dr Clarke says there might be some good news in that because we know more about the virus now than we did before – the winter months are not as difficult to cope with. “We might handle it better in the winter because we’ve been there, done that. We’ve got bigger testing capacity so people won’t go without a test and doctors and nurses know better how to treat it as well.”

But he does warn that people will need to be more aware of having winter colds and coughs, which frequently we would still go to work with. “People should be conscious that it is quite normal really once you hit late autumn early winter for people to cough or and sneeze – think how many times you’ve gone into work and people come in with colds.

“But an ordinary sniffle – people cannot assume that it is a cold this year because it might be something much more significant. Normally if you have that and take time off work that is frowned upon but I cannot possibly see how that will be allowed this year.”

Dr Clarke says that although something approaching normality is “desirable”, that politicians shouldn’t be “putting the idea in people’s head that December this year will be the same as December last year.”

Head agrees we can expect the measures that are in place now to still be in place until next year: “Infection control measures will be in place for many months and potentially years to come, and a complete return to the normality of 2019 will not be here any point soon.”