On Tue, 29 Mar 2022 09:40:28 +0200, Rolf Mantel <news@hartig-mantel.de> wrote:

>Am 28.03.2022 um 19:18 schrieb Charles Ellson:
>> On Mon, 28 Mar 2022 14:18:20 +0100, Recliner
>> <recliner.usenet@gmail.com> wrote:
>>
>>> On Mon, 28 Mar 2022 03:08:15 +0100, Charles Ellson <charlesellson@btinternet.com> wrote:
>>>
>>>> On Sun, 27 Mar 2022 23:23:32 -0000 (UTC), Recliner
>>>> <recliner.usenet@gmail.com> wrote:
>>>>
>>>>> Charles Ellson <charlesellson@btinternet.com> wrote:
>>>>>> On Sun, 27 Mar 2022 22:15:19 -0000 (UTC), Recliner
>>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>>
>>>>>>> Charles Ellson <charlesellson@btinternet.com> wrote:
>>>>>>>> On Sun, 27 Mar 2022 21:54:54 -0000 (UTC), Recliner
>>>>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>>>>
>>>>>>>>> Charles Ellson <charlesellson@btinternet.com> wrote:
>>>>>>>>>> On Sun, 27 Mar 2022 20:46:35 -0000 (UTC), Recliner
>>>>>>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>
>>>>>>>>>>> Charles Ellson <charlesellson@btinternet.com> wrote:
>>>>>>>>>>>> On Sun, 27 Mar 2022 15:53:01 +0100, Recliner
>>>>>>>>>>>> <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> On Sun, 27 Mar 2022 15:15:43 +0100, Roland Perry <roland@perry.co.uk> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>> In message <t1o8bo$p0d$1@dont-email.me>, at 23:41:44 on Sat, 26 Mar
>>>>>>>>>>>>>> 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>>>>>>>>>>>>>> Roland Perry <roland@perry.co.uk> wrote:
>>>>>>>>>>>>>>>> In message <atoe0djbfzse$.dlg@example1357.net>, at 19:37:01 on Thu, 24
>>>>>>>>>>>>>>>> Mar 2022, mechanic <mechanic@example.net> remarked:
>>>>>>>>>>>>>>>>> On Thu, 24 Mar 2022 11:06:55 +0000, Roland Perry wrote:
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> I first saw them at scale in a pub which had just reopened with
>>>>>>>>>>>>>>>>>> stringent Covid precautions. Tables separated, pre-booked only, one-way
>>>>>>>>>>>>>>>>>> system, one person in toilets at a time, table service only etc. It was
>>>>>>>>>>>>>>>>>> not at all clear what protection they gave either the waitresses or
>>>>>>>>>>>>>>>>>> customers.
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> That was when we were fed the 'droplets' theory, science is now
>>>>>>>>>>>>>>>>> reluctantly moving to the aerosol idea where earlier instructions to
>>>>>>>>>>>>>>>>> clean surfaces and wash hands have given way to more emphasis on
>>>>>>>>>>>>>>>>> ventilation and effective masks.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> I suppose I always did think it was mainly transmitted by the smaller
>>>>>>>>>>>>>>>> droplets know trendily known as aerosols, rather than spit and sneeze.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Still wouldn't want a Covid person to spit in my face though.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Breathing in your direction might be worse.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 2metres, 30 seconds, and both masked, shouldn't be an issue.
>>>>>>>>>>>>>
>>>>>>>>>>>>> No, probably not, but nor would spitting in those circumstances.
>>>>>>>>>>>>>
>>>>>>>>>>>> Saliva is generally a far better carrier of infection if it lands on
>>>>>>>>>>>> targer.
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Are you sure that's true of Covid? It's an airborne virus.
>>>>>>>>>>>
>>>>>>>>>> It isn't just airborne. The virus is present in saliva, mucous and
>>>>>>>>>> other bodily secretions. The difference with saliva (in original form)
>>>>>>>>>> is the practical need for more direct transmission from infection
>>>>>>>>>> source to entry route (e.g. snogging, spitting on target etc.) than is
>>>>>>>>>> needed with aerosols which generally require a relatively longer
>>>>>>>>>> presence to enable infection.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Would virus particles present in saliva get into a potential victim's
>>>>>>>>> airway?
>>>>>>>>>
>>>>>>>> Your airway starts at your nose and mouth. Coughing and sneezing can
>>>>>>>> cause a heavier and more concentrated stream of saliva than you get
>>>>>>>> with an aerosol.
>>>>>>>>
>>>>>>>> "The virus can spread from an infected person?s mouth or nose in small
>>>>>>>> liquid particles when they cough, sneeze, speak, sing or breathe.
>>>>>>>> Another person can then contract the virus when infectious particles
>>>>>>>> that pass through the air are inhaled at short range (this is often
>>>>>>>> called short-range aerosol or short-range airborne transmission) or if
>>>>>>>> infectious particles come into direct contact with the eyes, nose, or
>>>>>>>> mouth (droplet transmission)."
>>>>>>>> https://www.who.int/emergencies/diseases/novel-coronavirus-2019/question-and-answers-hub/q-a-detail/coronavirus-disease-covid-19-how-is-it-transmitted
>>>>>>>>
>>>>>>>
>>>>>>> A mask wearer is presumably reasonably well protected against droplets
>>>>>>> landing on their mouth or nostrils and then breathing in the particles. Is
>>>>>>> there any evidence that the virus can be transmitted via the eyes?
>>>>>>>
>>>>>> Your eyes drain internally to your nose via the nasolacrimal duct;
>>>>>> infection via the eye itself is less common. Eye protection is
>>>>>> standard kit for ambulance and first aid personnel dealing with
>>>>>> potential COVID patients.
>>>>>>
>>>>>
>>>>> Is that precaution based on actual evidence of risk from Covid, or simple
>>>>> (sensible) caution all infections?
>>>>>
>>>> The eye and associated areas have been regarded as a viable route of
>>>> infection for over a century :-
>>>> https://jamanetwork.com/journals/jama/article-abstract/220430
>>>>
>>>>> One thing we do know is that a lot of the often misinformed
>>>>> Covid precautions have at least protected against other illnesses in the
>>>>> last two years. For example, all that hand sanitisng didn't do much to
>>>>> block Covid but probably reduced food poisoning.
>>>>>
>>>> Without experimenting you have no proof for that. COVID was known to
>>>> persist longer on non-absorbent surfaces (e.g. handrails, door handles
>>>> etc.) while alcohol is efficient in destroying membranes that hold
>>>> viruses together as well as being a long-proven general antiseptic.
>>>
>>> I'm asking what actual research has been done about how Covid is spread. Or are they just assuming it's similar to other
>>> diseases (when we know it's not)?
>>>
>> There is plenty of research material available but as a novel disease
>> it is currently more heavily based on observation and experience.
>>>
>>>> Hand sanitising doesn't work when people don't practise it and I have
>>>> been around long enough to see that there are plenty of people who are
>>>> best described as selfish filthy bastards when it comes to considering
>>>> community hygeine.
>>>
>>> Yes, I agree that hand sanitising is good for public health, but just question whether it does much to slow the spread
>>> of Covid specifically. Has anyone done any actual research? They certainly hadn't when the advice was first given.
>>>
>> https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/897598/S0574_NERVTAG-EMG_paper_-_hand_hygiene_010720_Redacted.pdf
>>
>> Note that it can be inferred that standard door handles on
>> manually-opened doors, supermarket trolley/basket handles etc. are an
>> infection risk which simultaneous use of sanitisation should be
>> effective against.
>
>Wait a second: "hand sanitation is effective in reducing respiratory
>diseases". This is *not* research specific to COVID.
>
>My understanding is that in early 2020, hand hygiene was one of the
>"obvious things to do that might reduce transmission" but that by
>mid-2020 still there was no evigence of hand hygiene having an impact on
>transmission of COVID.
>
>Out of the three known pathways of transmitting respiratory diseases
>(smear infection via hand - eye or hand - mouth, droplet infection and
>aerosol infection) it is clear that for COVID, the dominant way of
>transmission is aerosol infection; it is not measurable whether smear
>infection is relevant for 10% of the infections, for 0.1% of infections
>or not at all.

Thanks, that confirms what I suspected.

Something noticeable in the UK is that the public authorities haven't updated their (incorrect) advice on Covid
transmission, nor the list of Covid symptoms from the early days of the pandemic. The ZOE studies have shown how out of
date these have become.

For example, I had a shingles vaccination appointment recently, and got sent an on-line questionnaire about whether I
was exhibiting any of what were obviously meant to be Covid symptoms. But they were all out of date, and not at all
representative of the then-current Covid symptoms. It didn't even ask if I'd had a recent positive Covid test, nor
request me to take a (free) LFT before showing up for the appointment. I wonder if it's any better in Germany?