Home News Coronavirus: Could HEATING protect against infection?

Coronavirus: Could HEATING protect against infection?

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Turning up the temperature inside buildings could reduce the spread of the coronavirus, scientists suggested in an advice paper to the Government.

Minutes from a meeting of the scientific advisory group SAGE showed that experts discussed the idea in May.

They said there was ‘moderate’ evidence that the virus would be less able to survive on solid surfaces in hotter environments.

The same has been found to be true of SARS, an almost identical virus, and SAGE suggested it could be an option for businesses where improving ventilation was not feasible.

One scientist explained the reason the virus becomes weaker at higher temperatures is that the molecules move around as they take on more heat energy. The movement can disturb and break the bonds between molecules and damage the virus’s structure.  

But Dr Andrew Preston, from the University of Bath, said it was unlikely that temperature changes tolerable in an office would make any real difference – and that the virus is clearly still able to survive at more than 38°C (100°F); body temperature.

SAGE did not suggest how hot a room would have to be to weaken the virus and make it less infectious. 

Businesses have for weeks been trying to find ways to reopen their doors to employees and customers to get the battered economy moving again, and high street stores have today reopened to the public for the first time since lockdown. 

Offices could be advised to turn the heating up high in order the protect staff from the coronavirus, Sage papers suggest (stock image)

Offices could be advised to turn the heating up high in order the protect staff from the coronavirus, Sage papers suggest (stock image)

The discussion by SAGE was mentioned in the minutes of its 35th meeting, held on May 12, which have now been published.

The minutes read: ‘There is some evidence for it [the coronavirus] becoming less stable at higher temperature and humidity within typical indoor operating ranges (moderate confidence), and some evidence that it is very stable at low temperatures (low confidence).

‘This could be reflected in operational guidance for relevant organisations, though the evidence for ventilation is stronger, so changes to temperature or humidity should only be considered where ventilation can still be maintained.’ 

The virus’s ability to survive for long periods on hard surfaces is one of the biggest barriers to stopping it, because people can pick it up on their hands without knowing.   

People are more likely to catch the infection in enclosed spaces with other people, where ventilation is poor and strangers touch the same surfaces regularly. 

WILL SUMMER ‘KILL’ THE VIRUS?

Studies suggest heat and humidity that is soon to come to the UK will only slightly reduce the transmission rate – not stop it in its tracks – which is why experts say being outdoors is ‘low risk’.  

For example, the most recently published study, on May 9, said transmission risk was only reduced by about 1.5 per cent for every degree Fahrenheit above 77F (25C). 

US and Canadian researchers analysed more than 370,000 cases in thousands of different cities in North America to come to the conclusion ‘summer is not going to make this go away’.

Another study by researchers at Beihang and Singhua universities, however, suggested rising temperatures and humidity ‘significantly’ reduced the spread.

Using their equation, if the temperature increased by 15°C, or 27 degrees F, an infected person would spread coronavirus to about 0.6 fewer people.  

The scientists also pointed out that in the early dates of the outbreaks, countries with relatively lower air temperature and lower humidity, like Korea, Japan and Iran, saw severe outbreaks. 

But warmer and more humid countries, like Singapore, Malaysia and Thailand, did not. 

A separate study that compared transmission rates with the weather in 224 Chinese cities concluded there was no relationship.  

‘Our analysis suggested that ambient temperature has no significant impact on the transmission ability of SARS-CoV-2,’ the researchers at Fudan University said.

‘It is premature to count on warmer weather to control COVID-19, and relying on seasonality to curb this pandemic can be a dangerous line of thought.

‘Changing seasons may help but are unlikely to stop transmission.’  

Commenting on the contradictory research, Professor Hunter said: ‘The coronavirus might spread less rapidly because people tend to be outdoors in the summer more anyway.

‘It’s an indirect impact – we are not as crammed in together during the summer. Schools are closed, people go away on holiday, and people sit in open air to eat rather than in restaurants. 

‘But, and there is a big but, a lot of the evidence for that is based on seasonal illnesses [like the flu].’ 

The paper did not recommend a temperature which would work to kill the virus and how this would work in a real-life setting. 

It also suggested changes to temperature should only be considered in places with poor ventilation. 

Scientists agree one of the best ways to improve infectious disease control in a building is with ventilation which help disperse virus-laden droplets inside. 

Commenting on the SAGE paper’s suggestions, Dr Preston, from the Department of Biology and Biochemistry at University of Bath, said he was doubtful a hike in heat could protect staff from catching the coronavirus.

He told MailOnline: ‘My suspicion is it would be hard to raise the temperature in an indoor workplace that would have significant effects that people would find bearable.

‘You start to notice environment at about 25°C (77°F). Although it’s possible it may help to reduce the virus, I can’t see taking the temperature from 20 (68) to 23°C (73°F) making a huge difference.

‘It would be such a slight contribution to infectious disease control. 

‘Although it might shorten the viruses stability from, say, 12 to 10 hours, that’s still no significant change to a person’s exposure.’

Dr Preston explained that heat breaks down bonds that keep proteins in the virus in shape.

As you increase heat, the energy causes molecules to move more and the bonds break. When proteins lose their structure, they lose their function and the virus becomes inactive. 

The lipid layer around the virus would also break down the same way as it would if disinfectant or anti bacterial hand gel was used.   

‘Clearly the virus can survive at 37°C (98.6°F), because that is body temperature,’ Dr Preston said – but it wouldn’t be realistic to ask people to work under those conditions.

He admitted there is research emerging to suggest high temperatures may play a role in suppressing the coronavirus.

For example, researchers at Beihang and Singhua universities suggested rising temperatures and humidity ‘significantly’ reduced the spread.

Using their equation, if the temperature increased by 15°C, or 27°F, an infected person would spread coronavirus to about 0.6 fewer people.  

The scientists also pointed out that in the early dates of the outbreaks, countries with relatively lower air temperature and lower humidity, like Korea, Japan and Iran, saw severe outbreaks. 

But warmer and more humid countries, like Singapore, Malaysia and Thailand, did not.

Countries like Brazil and India – with more than 867,000 and 333,300 confirmed cases, respectively – are still battling the worst of their outbreaks despite being warm countries. 

It suggests other factors, such as the strength of a healthcare system, population and age demographics or government decisions, would over-ride any protective effect of heat for limiting the spread.

Scientists say the virus is less able to spread outdoors because viruses UV rays in sunlight damages the genetic material, meaning people are less likely to pick them up from surfaces. 

And droplets containing the virus will be blown away quite quickly usually if there is a breeze.

Professor Alan Penn, a member of SAGE, the Government’s Scientific Advisory Group for Emergencies, reassured that those who flock to the parks that the risk of catching the virus outside is lower.

He said on May 13: ‘The science suggests that being outside in sunlight, with good ventilation, are both highly protective against transmission of the virus.’

Other scientists say they ‘totally agree’ with Professor Penn and advocate spending more time outdoors, where the virus is less likely to survive. 

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