Warm weather may have helped suppress coronavirus

Matt Woodley

20/02/2020 3:45:15 PM

But as Australia moves into its colder months, local experts maintain quarantine efforts such as good hygiene and self-isolation are still the most important factors.

Warm and cold weather
Cooler weather aids the spread of most respiratory viruses, but it is not known if this applies to the new coronavirus.

Recent leaked comments attributed to Professor John Nicholls from the University of Hong Kong’s Department of Pathology suggest he believes weather conditions will be a key factor in the demise of the coronavirus.
Speaking during a conference call organised by Hong Kong-based brokerage firm CLSA, Professor Nicholls referenced the 2002–03 SARS outbreak and said environmental conditions – such as temperature, humidity and sunlight – are a ‘crucial factor’ in a virus’ ability to survive and infect people.
‘Sunlight will cut the virus’ ability to grow in half, so the half-life will be two-and-a-half minutes and in the dark it’s about 13–20 minutes. Sunlight is really good at killing viruses,’ he said.
‘That’s why I believe that Australia and the southern hemisphere will not see any great infection rates because they have lots of sunlight and they are in the middle of summer. And Wuhan and Beijing are still cold, which is why there’s high infection rates.
‘In regards to temperature, the virus can remain intact at 4⁰C or 10⁰C for a longer period of time. But at 30⁰C degrees then you get inactivation. And high humidity, the virus doesn’t like it either.’
But while Australia’s warmer weather has theoretically helped protect the population from a wider outbreak to this point, the coming colder months may have the reverse effect.
Professor Nicholls suggested the common cold is a better comparison to the new coronavirus than SARS or MERS, as he believes there has been a ‘severe underreporting’ of cases in China that has contributed to inflated fatality rate estimates.
‘Basically, this is a severe form of the cold,’ he said.
‘The environment is a crucial factor. The evidence is to look at the common cold – it’s always during winter.’
However, Dr Kerry Hancock, Chair of the RACGP Specific Interests Respiratory Medicine network, told newsGP she thinks the containment of coronavirus disease (COVID-19) in Australia has so far been a result of good quarantine practices and not necessarily related to current weather patterns.
‘Cooler weather provides more favourable conditions for the spread of most respiratory viruses, of which the most common are the coronaviruses – such as the common cold,’ she said.
‘However … there is currently no available evidence about how temperature and humidity affects transmission of COVID-19.’
Instead, Dr Hancock said good hygiene practices are a more important determining factor.
‘With the colder weather approaching … [and] the community potentially in closer contact with each other and the potential increase in circulating respiratory viruses, which may include COVID-19, we need to emphasise continued vigilance with good hygiene practices,’ she said.
‘Everyone should practise good hygiene to protect against infections. Good hygiene includes washing your hands often with soap and water, using a tissue and cover your mouth when you cough or sneeze, avoiding close contact with others, such as touching.’
Dr Hancock’s comments mirror those of Professor Lyn Gilbert, Chair of the Infection Control Advisory Group (ICAG), who previously told newsGP hygiene is vital for preventing the spread of coronavirus.
‘When people cough and sneeze, they either contaminate their hands, or droplets fall on hard surfaces – people touching [these surfaces] is probably the major route as much as direct droplet spread,’ she said.
‘This is why we keep on emphasising hand hygiene and frequent cleaning of surfaces in rooms where patients who are infected have been.’
The spread of the coronavirus, particularly outside the outbreak’s epicentre of Hubei Province in China, appears to have been slowing in recent days – despite fears of major outbreaks in Japan and Singapore.
As of Thursday 20 February, Australia had not recorded a new infection in two weeks. Nearly 78,000 people have been infected worldwide, resulting in more than 2100 deaths.
The RACGP has more information on coronavirus available on its website.
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Prof C Sense - just call me Common   21/02/2020 11:54:54 AM

While I understand the need to get opposing points of views as a journalist - some of the opinions sought are just plain irresponsible at best, outright dangerous at worst. For example: “ thinks the containment of Australia has so far been a result of good quarantine practices and not necessarily related to current weather patterns.” My follow up question to this assertion is: what quarantine practices have been put in place in Australia? And what makes these practices so effective? Australia has implemented self quarantine! Is this what she means by “good quarantine practices”? Self quarantine still means there is exposure to the general population. Whether the person is honest or not who can tell? It is only dumb luck Coronavirus is not more widespread. If weather contributes to that I would be happy to accept that and hope there’s no further cases coming into the country.

A.Prof Christopher David Hogan   21/02/2020 9:02:14 PM

The scientific method consists of observation, supposition & experimentation. The above is supposition not proof.
When inconsistencies such as low secondary spread outside China occur there are lots of suggested - as there should be. I have heard some incredible suggestions but I await good evidence