Transmission of COVID-19 Is Influenced by Temperature, Humidity and UV Radiation, Study Finds
The issue of COVID-19’s seasonality has been covered extensively on Lockdown Sceptics. Back in February, Glen Bishop noted that a model developed by Imperial College researchers – which predicted there would be an additional 130,000 deaths this summer – assumed that transmission does not vary by season.
In a follow-up article, I reviewed eight separate studies that found evidence for the seasonality of COVID-19. Indeed, it would be rather surprising if COVID-19 wasn’t seasonal given what we know about other human coronaviruses, i.e., that they are – in the words of one recent study – “sharply seasonal”.
However, doubts have been expressed about whether COVID-19 is in fact a seasonal disease. Such doubts are based on the observation that countries like Chile and South Africa saw epidemics burgeon during their summer months, and that Britain itself is now seeing a rise in cases.
But as the biologist Francois Balloux notes in a recent Twitter thread, the fact that some countries have seen infections rise during the summer is not inconsistent with seasonal factors playing a role in transmission. It just means they aren’t the only factors involved. (One also has to consider viral evolution, population immunity and human behaviour.)
A new study by researchers from Yale and Columbia (which was published in the journal Nature Communications) offers particularly strong evidence for the seasonality of COVID-19. The authors looked at the relationship between seasonal factors and the R number across US counties between March and December of last year.
They ran a statistical model of the R number, with temperature, specific humidity and UV radiation as predictors. The model controlled for a range of other factors, including spatial, demographic and socio-economic variables.
The authors found that each of the three seasonal factors was independently associated with R. They then calculated the fraction of R that was attributable to seasonality, and obtained a value of 17.5%. Interestingly, specific humidity was the most important of the three, contributing 9.4%.
The authors’ findings indicate that “that cold and dry weather and low levels of UV radiation are moderately associated with increased SARS-CoV-2 transmissibility”. However, they were unable to examine possible differences in seasonality across different variants, leaving this as a topic for future research.
Overall, their study provides some of the best evidence yet for seasonality. And it gives one more reason to be sceptical that the current rise in cases here in Britain portends a major epidemic.
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“ And it gives one more reason to be sceptical that the current rise in cases here in Britain portends a major epidemic”
from the information we have it doesn’t look at all like its going to be an epidemic. its not rising exponentially for starters. it was rising linearly (which means falling R value). now even that looks like its levelling off.
My biggest annoyance…exponential growth!!! In March 2020 when we went from 10 to 100 to 10000, that was exponential growth. Going for 2000 to 10000, while not good, is a mere doubling 2.5 times.
And since overall hospital numbers have risen by a tiny percentage (relative to overall number), cases have as much merit as do budget projections.
interestingly the R went from 1 to 1.8 in a few days and has come back down to 1.1
that looks very much like herd immunity has been achieved and there’s just the occasional pocket/outbreak
if we weren’t looking for it there would literally be nothing there
hospitalisations, deaths – everything is normal.
this is all panic about the output of some shit models
Infections can only approximate an exponential function for a very short time.
Then Herd immunity builds with the effect of having previously infected people around and that slows it down.
I think many people do not understand the true meaning of exponential growth. Compound interest of 0.5% interest per year still leads to exponential growth. At that rate, a sum will double every 140 years. The fact that it is doubling over a set period means that it is growing exponentially.
“it gives one more reason to be sceptical that the current rise in cases here in Britain portends a major epidemic”
Oh dear! – does anyone with a brain and a clear conscience believe that, given that there has never been an ‘epidemic’ by the officially defined community level (see CEBM).
This is a nasty little, largely nosocomial, infection of no high consequence that is well within the normal range of impact, and which, if you believed Mr Toad and his fellow creatures, behaves like no other virus ever has. But actually does.
‘R’ numbers are just airy guesses.
Seasonality could be as simple as which part of the year do you spend most time under a roof.
With the windows closed.
My suspicion would be parts per million in the airflow. UK homes in particular are notoriously under ventilated.
and what have the government been busy doing? Oh yes, making sure all homes are hermetically sealed because “global warming is going to kill us all”.
Quite the reverse, I hate to say. If you wanted to take advantage of insulation grants you home was inspected and if it wasn’t up to current building regs standards. I applied but found I would need trickle vents fitted to all my windows and an extractor fan fitted in my bathroom (an opening window has been good enough for me for 35 years).
They are very keen on getting rooms ventilated.
Or to be seen to be following EU legislation?
What a load of wank!
There’s no fucking Covid-19 anymore, and those findings will be the same for all seasonal illnesses.
Yet another article to confuse and obfuscate.
Really interesting article. It beggars belief that scientists are still actually grappling with this.
It is a matter of common folk lore in the Western Hemisphere that you want to get sick in the Summer because your recovery is better than winter. And a more modern take is that you’ll want to get elective surgery over Summer because your recovery from whatever hospital acquired infection you pick up will be faster. (Note that amongst those of us under the NHS knife more often than most, any hope of avoiding a hospital infection is pretty much absent).
This rule of thumb is pretty sound, (although mine now is to take all elective surgery privately, if possible).
The 130k was always bogus precisely because of seasonality. I’d be interested to see the impact of high heat in locations with high air conditioning (Texas, Florida et al). They saw bumps at odd times due largely being forced inside.
Here it is important to note the inspect of the cold and grey May we just had. Especially in the North, where the outbreaks remain strongest (spent enough soggy Mays in Manchester for this life, even as much as I love it there). Had the Indian variant arrived in a hot spell (say, summer of 2020), would we see even half the numbers we do now?
The lack of seasonality in the models should have told Boris the models were worth less than soiled loo roll paper. Alas he can read Latin but is a babbling toddler around numbers.
here are the predictions
“Alas he can read Latin but is a babbling toddler around numbers.” Well, he is said not to be a detail man, and that’s quite plausible, but seriously, anyone with an IQ > 85 could work out that the models are cobblers. He’s a bullshitter, and they usually can tell other bullshitters when they see them. He’s lying.
“outbreaks”
What ‘outbreaks’ in any meaningful sense of the word?
Humid air quickly turns an aerosol into a droplet which then falls to the ground, rendering any respiratory viruses within harmless.
So their messing with the weather won’t help!
Of natural factors, humidity must play the greatest role, When air is wet , droplets
containing anything drop quickly to the ground, so infectiousness declines.
Human mingling plays the next most important role. When people change jobs, housing, locations, children start new school years etc, previous herd immunity for any virus changes/reduces for a time until new herd immunity is regained. This happens regularly in the September/October period in the NH.
None of this is new or ‘rocket science’.
Hope-Simpson noted this regarding influenza, the presence of disease being related to latitude as well as time of year, with different infection curves.
Corona viruses can start to appear in late summer peaking in late autumn or early winter.
Epstein-Barr virus starts to appear in September/October, particularly in universities.
Coughs and colds appear in children in September, particularly in those starting school.
Is it coincidence that SARS appeared in 2003, MERS in 2012 and SARS-2 in 2020?
Asian flu 1958 and Hong Kong flu in 1968? Of course this is correlation not causation.
Ultraviolet radiation from the sun varies with the 11 year/22 year solar cycles.
A virus is not seasonal, we are.
I agree. The human is always forgotten in all of this.
Well, whatever the influence of seasons, the evidence of what doesn’t influence spread is pretty clear: govt interventions, lockdowns, masks, mass testing, mass vaccination, quarantining the healthy, track and trace, travel bans, covid passports, hand washing, social distancing.
Overall, their study provides some of the best evidence yet for seasonality. Seasonal impact of the virus has been bloomin’ obvious for a year. Along with many others I predicted every fake up and down turn for C19, as it was simply mapped onto previous years respiratory ailment graphs from ONS. The stony faced announcement of second spikes when seen against what happens every year were laughable, Although a little late in the scene in 2020 the way c19 susceptibility precisely adapted and followed the subsequent winter’s expected increase>peak>decline in flu cases was impressive. Yes, it was well at home in our grey & sniffly lands. If it acts like a flu, if it feels like a flu, if our antibodies fight it off like a flu, if we are more susceptible seasonally like a flu then it is probably a flu – or at worst a proxy flu. This is hardly surprising, however, as most C19 cases aren’t C19 at all – just the usual colds and flus (or their remnants) re-branded by over active PCR testing as C19. The fact that seasonal flus declined or vanished altogether in this process tends to be a bit of a giveaway… Read more »
Here we go people of Earth.
Viruses outnumber stars by a factor of 10 million. If you lined them all up, that line would be 10 million light-years long! To put it on a more conceivable scale, it’s been (link) estimated that each day, more than 700 million viruses, mainly of marine origin, are deposited from Earth’s atmosphere onto every square meter of our planet’s surface.
Better stay in my cave forever!
Indeed. As I pointed out whenever there is a new ‘variation’ discovered, it will take days to travel everywhere around the globe by natural means. The very idea of it hoping on and off aircraft is ludicrous.
Most new annual flu bugs originate in S E Asia, then travel around the globe. By looking there first they try to guess which flu strain will hit N America and Europe in that year and modify the vaccine. The bug does not need airline tickets to do this.
Its as if real scientific thought has been deliberately erased to be replaced by ‘the science’ which is a diatribe designed to support political and economic motives.
Is there a reasonable explanation as to why annual ´flu bugs should originate in S E Asia? Has the Wuhan Lab been active for decades?
The explanation I recall is that Chinese agriculture includes pigs, ducks and humans in close proximity, so the various strains of bird and swine flu get to exchange parts of their genetics with human ones.
“Britain itself is now seeing a rise in cases.”
No it isn’t – in any meaningful sense. The numbers are trivial, based on a fraudulent definition of ‘the term ‘case’. You could find the same variation for a multitude of RNA scraps.
This isn’t news. The indications have been around for a year, with latitude being a clear correlate.
Exactly. The cases are almost entirely a function of increased testing in the supposed “hotspots” and the false positive rate of the PCR test.
… and just look at that brief exponential rise in December, just as ‘cases’ are subsiding. Actually a pretty good match with the introduction of vaccines
Getting out in the fresh air, exercising and meeting other people works. Wow!!!
I told the fecks that in March 2020
Another study that’s just found the bleedin’ obvious, that seasonality is a factor which affects respiratory viruses. If it wasn’t for all the lying politicians, ‘celebrities’, ‘experts’, ‘scientists’ and ‘journalists’ etc. incessantly telling us that black is white, we wouldn’t need a study to tell us that black is black.
The British Isles must have a very different climate to mainland Europe then, which has had a decline in +tests, especially Germany, which is very steep indeed. And they cannot claim it is a successful vaccination campaign, as they had about 30% done when the decline started.
But if history repeats itself, future history books will be stating that the Covid vax saw the decline of the virus.
Hancock says the PM was ‘stressed’. That sounds like a get out of jail card for any indiscretion an individual might make and come to regret (or not, in Johnson’s case). Perhaps Olly Robinson should take that defence.
Two things.Firstly, at LS.org we all know the fraudulent results obtained by mass testing, certainly when also considering the cycle threshold employed. A positive test [most often] does not equal a symptomatic infection.
Secondly, it is now coming to light that vaccination is causing genuine cases and there has been / is a [sadly] successful vaccination program. Also, it has been remarked that the spike protein generated by the vaccination reactivates latent virus’ in ones body and this is why one of the adverse reactions is people coming down with shingles (for example).
The end result is that the factors that create the argument for seasonality are being skewed and / or faked.
I also meant to paste in a graphic generated by our friend Ivor Cummins. It shows the rise of the Delta variant in purple and hspitalisations as the green line. This is the reality.