COVID-19: WHY THE COMING AUTUMN AND WINTER IS A CONCERN

Many respiratory viruses such as 'flu have a 'season' when infections rise.  This is typically over the winter.

In Europe we've only seen COVID-19 in the spring and summer so far. But there's every expectation that the same thing will happen as the weather turns colder into October and beyond.  Infections will naturally occur more easily.  In Melbourne Australia, where it has been winter, infections have risen steeply.

There are several reasons:

• Indoors versus outdoors
• Lower temperature
• Less sunlight
• Students at universities

  
INDOORS vs OUTDOORS

The most important reason infections rise in colder months is that people will spend more time indoors, and increasingly windows will be shut so there's less ventilation.  That gives the virus more chance to linger in the air on microdroplets and be breathed in by other people.

Masks and face coverings catch many of the microdroplets that a person breathes out, thereby reducing the risk of an infectious person inecting other people.

Lingering in the air is especially true in the home, where infection can spread through the household.  It has been shown that most infections happen in the home, where of course people spend a lot of time in close proximity, without wearing masks.  It only needs one infectious member of the household for several more to be infected.  Be that family or friends, which will become a more important issue when students are back at university.

Outdoors the breeze takes the viruses away and in any case dilutes them, just like a cloud of tobacco smoke disperses.

This is why I have had a rule to only meet up with people outdoors, not indoors. Except for essential shopping like food. And why getting my hair cut and 'lockdown beard' trimmed was such an issue.


LOWER TEMPERATURE

A virus is inanimate, but the SARS-COV-2 corona virus that causes COVID-19 has a structure that allows the protein spikes on its surface to get into a human cell.  There the viruses get reproduced and kill the host cell.  The new viruses go on to infect other cells.

Disrupt the structure and a virus cannot function.  Viruses do not survive on surfaces for very long, up to three days for some types of surfaces.  That's as the structure breaks down.

The virus is surrounded with a fatty lipid coating.  Cool it down and the coating  hardens, warm it up and it gets softer.  The virus will become more stable at lower temperatures, and therefore more of a risk.

The source of the August outbreak in New Zealand is still not known, but could be a cold store facility where the first man to be tested positive worked.

Cold temperatures may also be a factor in why many factory outbreaks have been at meat and food processing plants where temperatures are kept low. 



DISRUPTION FROM UV

A bus treated with UV

We all laughed when President Trump suggested we should drink disinfectant and put ultra-violet UV light into our bodies.  Not that those ideas wouldn't work.  Just that the damage would be considerable.

Indeed UV light is now commonly used to de-activate the viruses on surfaces, such as in ambulances, buses, offices and schools.  Though only when humans and any other life is absent.

Sunlight includes UV.  Although some frequencies are better at de-activating the viruses, the more sunlight, the less viruses. 

Conversely, the less sunlight, the longer the viruses will last, both in the air and on surfaces.

Going indoors, and then the dwindling sunlight getting through the windows, gives the viruses a better chance of survival, and therefore of causing infection.


STUDENTS AT UNIVERSITIES

Typical at university

As indicated above, the most infections happen in households.  Not just families, but groups of friends.  That includes students packed into halls of residence and student houses with significant shared facilities.

Especially when younger adults are often flouting social distancing and other sensible precautions.  

It just so happens that students are now starting to return to universities.  Just when the opportunity to be outside in relative safety is reducing.  Watch this space, I fear.


IN CONCLUSION

There are several reasons why COVID-19 would naturally become more infectious as summer changes into autumn and winter.

It would have been sensible to get infections down to a very low level, #NearZero, so the base from which infections would grow was lower.  That would have also allowed the economy to take off more strongly, and a host of other benefits. Given where we are after the first lockdown, #NearZero is the only way.