implications for infection prevention precautions

Kassem CC BY-NC-SA 9/07/2020

Dernière mise à jour de l’#OMS sur les modes de #transmission du #SARS-CoV-2 et les implications pour la #prévention et les #précautions ;
▻https://www.who.int/publications-detail-redirect/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution
▻https://apps.who.int/iris/rest/bitstreams/1286634/retrieve

L’OMS, tout en acceptant l’hypothèse de la transmission par #aérosol, continue de donner une importance plus grande aux gouttelettes et elle persiste à estimer que les cas #asymptomatiques sont peu contagieux.

La partie sur la transmission est résumée par Helen Branswell sur Twitter : ▻https://mobile.twitter.com/helenbranswell/status/1281274685616001024

WHO issued an update on how #Covid19 transmits. It says:
a) In some cases/places short-term aerosol transmission can’t be ruled out, though droplet & fomite transmission could also explain these cases.
b) Most transmission occurs via droplets, from symptomatic people." /
c) most transmission seems to occur when people have symptoms or just before they develop symptoms.
d) it’s not clear how often people who are truly asymptomatic — never have symptoms — transmit. Percentage thought to be low
e) Fomites (virus on surfaces) are considered a likely mode of transmission, but no clear cases yet.
f) Not clear if transmission through blood is possible; risk seems low.

Kassem CC BY-NC-SA

Kassem @kassem CC BY-NC-SA 9/07/2020

Selon l’OMS, la transmission aérienne du virus « ne peut pas être exclue »
▻https://www.lemonde.fr/planete/article/2020/07/09/coronavirus-selon-l-oms-la-transmission-aerienne-du-virus-ne-peut-pas-etre-e
https://img.lemde.fr/2020/07/09/880/0/5800/2897/1440/720/60/0/3cf94d7_615255773-000_1UJ5OX.jpg

Kassem @kassem CC BY-NC-SA
Kassem @kassem CC BY-NC-SA 10/07/2020

Q&A : How is COVID-19 transmitted ?
▻https://www.who.int/news-room/q-a-detail/q-a-how-is-covid-19-transmitted
Mis à jour hier.

Kassem @kassem CC BY-NC-SA
Kassem @kassem CC BY-NC-SA 12/07/2020

WHO still skeptical SARS-CoV-2 lingers in air—despite what the NYT says | Ars Technica
▻https://arstechnica.com/science/2020/07/no-the-who-has-not-reversed-its-stance-on-airborne-transmission
https://cdn.arstechnica.net/wp-content/uploads/2020/07/GettyImages-1224562968-760x380.jpg
In its updated scientific brief on transmission, the WHO said, basically, the same thing it has said for months on airborne transmission. That is: the question of whether SARS-CoV-2 lingers in the air is a topic of active discussion and, while it may be possible in some settings, the data in aerosol transmission so far is inconclusive or unconvincing. But, as always, the WHO welcomes more high-quality research on this topic.
In the latest brief, the WHO reviewed recent physics studies looking at aerosol production, but it noted: “the proportion of exhaled droplet nuclei or of respiratory droplets that evaporate to generate aerosols, and the infectious dose of viable SARS-CoV-2 required to cause infection in another person are not known.” It reviewed experiments on droplets and aerosols from normal speech and coughing and concluded, “To date, transmission of SARS-CoV-2 by this type of aerosol route has not been demonstrated; much more research is needed.” Likewise, studies using nebulizers to suspend SARS-CoV-2 in the air “do not reflect normal human cough conditions,” the WHO concluded.
The WHO noted that clinical reports of exposed health workers “suggest that aerosol transmission did not occur in this context.” And, the organization added, air sampling in health care settings has been inconsistent in finding genetic traces of the virus
Perhaps there was some rush to declare victory in the great aerosol war because the WHO did discuss recent reports of possible airborne transmission in specific outbreaks.

Kassem @kassem CC BY-NC-SA

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