Masks and Covid spread
Thread Starter
Masks and Covid spread
[OK, this post is to ask a question because I don't know the answer...not take a stand on the issue one way or the other. I'm a layman, not a doctor]
We are exhorted (if not required) to wear masks to prevent the spread of COVID. Yet in May, the CDC published an article on the spread of influenza saying that masks are ineffective in preventing its spread.
I know influenza isn't COVID but the physical process of disease transmission is the same for both diseases: aerosolized water droplets from one person's nose or mouth get into the nose or mouth of another person.
https://www.cdc.gov/flu/about/disease/spread.htm
So if a mask is ineffective in preventing the spread of influenza, why is it being touted as effective in stopping the spread of COVID ? Most people I see are NOT wearing N95 masks. And many people I see aren't wearing a mask properly anyway...including those in what appears to be N95-type masks.
Here's the CDC info from May re influenza:
"Although mechanistic studies support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza."
"Disposable medical masks (also known as surgical masks) are loose-fitting devices that were designed to be worn by medical personnel to protect accidental contamination of patient wounds, and to protect the wearer against splashes or sprays of bodily fluids (36). There is limited evidence for their effectiveness in preventing influenza virus transmission either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure. Our systematic review found no significant effect of face masks on transmission of laboratory-confirmed influenza."
https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article
We are exhorted (if not required) to wear masks to prevent the spread of COVID. Yet in May, the CDC published an article on the spread of influenza saying that masks are ineffective in preventing its spread.
I know influenza isn't COVID but the physical process of disease transmission is the same for both diseases: aerosolized water droplets from one person's nose or mouth get into the nose or mouth of another person.
https://www.cdc.gov/flu/about/disease/spread.htm
So if a mask is ineffective in preventing the spread of influenza, why is it being touted as effective in stopping the spread of COVID ? Most people I see are NOT wearing N95 masks. And many people I see aren't wearing a mask properly anyway...including those in what appears to be N95-type masks.
Here's the CDC info from May re influenza:
"Although mechanistic studies support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza."
"Disposable medical masks (also known as surgical masks) are loose-fitting devices that were designed to be worn by medical personnel to protect accidental contamination of patient wounds, and to protect the wearer against splashes or sprays of bodily fluids (36). There is limited evidence for their effectiveness in preventing influenza virus transmission either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure. Our systematic review found no significant effect of face masks on transmission of laboratory-confirmed influenza."
https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article
Last edited by bafanguy; 25th Sep 2021 at 23:13.
Great question
Influenza is mostly spread by droplets and covid by aerosol. Simple? No. There are many studies showing mask wearing reduces the number of Covid cases but it is almost impossible to significantly increase mask wearing without changing the influence of other non pharmaceutical interventions or NPIs such as testing, spacial separation and behavioural changes. In addition each wave has a natural duration - in the UK the waves were already falling in waves 1,2 and may be 3 before lockdowns for which the politicians gave thenmselves gold stars
The N95 is called FFP2 in europe (not exaclty the same) and N99 is called FFP3. The latter may have a valve which spews out virus and only protects the wearer whereas an N95 only protects others.
At the end of the day the Delta variant is now king, accounting for 95% in the US. There is good news from this in so far as it is so infectious that it is unlikely a further variant can beat it and however lethal a variant is it can only surplant an existing strain if it is more infectious. However that means NPIs have less benefit.
The answer is vaccination, and three doses. This will provide adequate immunity in individuals and across society to return to normal life except for the immunosuppressed and I have posted before that I believe they need not only better identification (do patients with Chron's disease appreciate they are high risk?) but legislated protection. Vaccination however only protects you, not others as even when vaccinated you may well be breathing out virus, mask or not.
So I havent really answered your question but the advice is to get triple vaccinated, protect the immunosuppressed and meantime a mask may help and cant do harm.
Influenza is mostly spread by droplets and covid by aerosol. Simple? No. There are many studies showing mask wearing reduces the number of Covid cases but it is almost impossible to significantly increase mask wearing without changing the influence of other non pharmaceutical interventions or NPIs such as testing, spacial separation and behavioural changes. In addition each wave has a natural duration - in the UK the waves were already falling in waves 1,2 and may be 3 before lockdowns for which the politicians gave thenmselves gold stars
The N95 is called FFP2 in europe (not exaclty the same) and N99 is called FFP3. The latter may have a valve which spews out virus and only protects the wearer whereas an N95 only protects others.
At the end of the day the Delta variant is now king, accounting for 95% in the US. There is good news from this in so far as it is so infectious that it is unlikely a further variant can beat it and however lethal a variant is it can only surplant an existing strain if it is more infectious. However that means NPIs have less benefit.
The answer is vaccination, and three doses. This will provide adequate immunity in individuals and across society to return to normal life except for the immunosuppressed and I have posted before that I believe they need not only better identification (do patients with Chron's disease appreciate they are high risk?) but legislated protection. Vaccination however only protects you, not others as even when vaccinated you may well be breathing out virus, mask or not.
So I havent really answered your question but the advice is to get triple vaccinated, protect the immunosuppressed and meantime a mask may help and cant do harm.
Why only 3 doses, flu vaccine is every year and still thousands die. We will have to accept that people will perish from viral infections, life is not without its risks. The saying of Death and taxes could not be more true.
Thread Starter
Radgirl,
For us laymen, what's the difference between droplets and aerosol ?
The news hacks are calling the mess in the USA the "pandemic of the unvaccinated" where 90+% of the hospital beds are said to be occupied by those who refused to get the shots.
I'm waiting for the Imperial Federal Kakistocracy to tell me when I can get my 3rd shot. They are worse than the disease.
For us laymen, what's the difference between droplets and aerosol ?
The news hacks are calling the mess in the USA the "pandemic of the unvaccinated" where 90+% of the hospital beds are said to be occupied by those who refused to get the shots.
I'm waiting for the Imperial Federal Kakistocracy to tell me when I can get my 3rd shot. They are worse than the disease.
Why only 3 doses, flu vaccine is every year and still thousands die
Covid 19 doesnt mutate much - it appears to have a checking system at replication that discards mutation. Mutation has been at a small area on the virus, and so the same vaccine will likely work in the future.
The third dose produces 7-11 TIMES as many neutralising antibodies as the second dose and while not proof it suggests the third dose MAY provide much longer immunity as does repeated hepatitis B vaccine. At the end of the day we wait for the evidence but the world is already making enougth vaccine for the entire planet every year (there is a subject for another thread) so if we do need another top up it isnt that difficult at least in the developed world
what's the difference between droplets and aerosol
You cant have a combination - the particle is either hyperbaric or hypobaric. However as I said above, I do not think the issue is so simple - my conclusion is that masks are not a clearcut benefit, NPIs taken as a whole are. Data must be considered carefully - the CDC reference you provide does advise covering the face to sneeze...and staying at home. I am a sort of scientist, not a politician so I can say I dont know 
Absolutely none...
