As I lay in the dentist's chair today, hopefully protected from bacterial infections by my antibiotic prophylactic, I watched the occasional fireworks as fine droplets, expelled when I talked, sparkled in the strong light above my head. This prompted me to ask the protectively masked and visored dental hygienist, "how long had it been since face masks became standard dental wear?". She couldn't remember, but said it had been at least 10 years, and my dentist could remember that forty years ago dentists didn't even wear latex gloves when doing fillings.
Face masks became more common in Australia with the H1N1 flu epidemic and there's a box of them prominently displayed for use where I get my blood tests done. I'm also asked to use hand gel wash before entering the room to be stuck in the arm. Hand gel wash bottles are also commonly seen at entrances to doctor's rooms here, but unfortunately I don't see them used much. You are also requested to ask for a mask while waiting for the doctor if you have a cough. Good etiquette when you coughed or sneezed was to cover your mouth with your hand - and then shake hands. Thankfully it is becoming more common to cough or sneeze into your elbow. Very slowly, we are adopting simple, low cost techniques to reduce the spread of infections.
To be effective, a surgical or procedure face mask, needs fine pores to filter out droplet borne viral and bacterial particles. This degree of filtering means it is much easier for air to get through any gaps between the mask edge and your face than to travel through the mask, so you need to mould the mask around your face and pinch the metal strip against your nose to improve the seal. If your mask doesn't fit well, then you are largely inconveniencing yourself for little benefit. Even a well fitted mask is still only about an 85% effective barrier, but that 85% could be the difference between life and death for us. If you wear glasses, look for the anti-fogging variety, particularly during colder seasons.
I now also wear a dust mask when handling potting mix (and dampen the potting mix if it's dry) after hearing of a CLL mate being admitted to Emergency with a raging fever the night after using potting mix without a mask.
I notice Brian Koffman is preparing for a masked "ball of a time" * on his trip to the Emerald Isle. Why aren't more of us doing it in this heightened flu risk season?
I'd be interested to hear from around the world about how common procedure mask wearing is, suggestions for the differences and ideas on what we can do to improve society's health. As John says in the first referenced article below about how common mask wearing is in Japan: "I wish more people in the United States did this.."
Wearing a mask certainly protects others, how much wearing a mask helps the wearer is pretty debatable... certainly some protection.
Only certified partiulate masks have any pathogen benefit to the wearer and it is limited...NIOSH N95 or N99 . They may filter out some bacteria and fungi...but most viuses pass right through...
Obviously N99 are better than N95...better filtering...but hard to breath through, if fitted correctlly... and tight fit is imperative as Neil mentioned.
Masks are warn in medicine to help prevent air borne transmission of pathogens from the wearer to the patient... the whole idea that a patient wearing a mask gets much benefit, is actually rather speculative and poorly researched...
Particulte masks are a filter ...plain and simple... if the pathogens are larger that the mask 'holes' they get filter out...if the are smaller than the holes..they pass right through unimpeded.....most viruses infact do exactly this...
Further...bacteria and fungi trapped in the mask...have hit Nirvana...warmed by the flow of breath and moisture...they just love it... so they multiply rapidly...therefore masks need to be changed frequently ...
There was a wonderful chart during the SARS outbreak, that showed 100 of the top pathogens and based on size showed if a N95 mask would stop them or if they passed right through... I can't find it at the moment, but will post the link if I find it...
Watch for counterfit masks too..there are many on the market... totally useless...
The only way to get full protection is to use an Self-contained breathing apparatus, these are often used with stem cell transplant patients...full facemasks and closed loop SCBA.
Good information on the use of masks etc, to slow aerosol and droplet transmitting of influenza viruses...this link...
Thanks for your input and the extra information Chris.
Per your last link, "Traditionally, influenza viruses have been thought to spread from person to person primarily through large-particle respiratory droplet transmission (e.g., when an infected person coughs or sneezes near a susceptible person). Transmission via large-particle droplets requires close contact between source and recipient persons, because droplets generally travel only short distances (approximately 6 feet or less) through the air..." From the first sentence, obviously a lot more research is needed!!
Yes procedure masks are only part of the solution, which extends to wearing gloves, apron or gown, eye protection, shoe covers or in the extreme a 'moon suit'. If someone obviously ill coughs or sneezes over me even when I'm wearing a mask, I'd only feel more confident about avoiding infection after stripping off my outer clothing and having a shower!
IF the traditional idea on how influenza viruses are spread is correct, then a N95 mask will block virus carrying droplets, but as you say, you need to replace the mask frequently. My dental hygienist says she changes hers after around 30 minutes. Sounds like it's advisable to wash your hands after removing your mask and it definitely would not be a good idea to reuse a mask after leaving it say overnight, which would give time for the droplets to dry out and release the virus particles so they can get through the pores.
Perhaps masks can be most effective for us due to their repellent effect? Might be a good way to guarantee breathing space if you need to use public transport!
Hi everyone, I've been reading these comments with interest, I have no experience of masks but at Lincoln hospital, where I attend every 3 months for blood test, I have noticed a lot more hand gels for public use. Just like many others, once they have taken my blood I wait for over an hour plus to get results. Whilst waiting I can observe people coming in and out, whether patients, carers or visitors and very few use the gels
I buy boxes of 50 from the Chemists; they work out at about 20 UK pence per mask. I can also buy them direct from the distributor in a 6 pack = 300 masks. That way they work out about 15 pence each including courier delivery. Colours are limited to blue and white (plus a child mask with coloured spots). I'll leave it to you to make your fortune exploiting the world market for coloured masks!
Hi if you didn't have a mask wouldn't just a clean hankie held over mouth and nose be ok and less weird than a mask. I use the London tube which is a breeding ground for germs.
Masks are many times finer filters than a hankie ...even so viruses will pass right though...
N95 masks, have but ONE purpose: To prevent the wearer from infecting others. Thus, if the wearer sneezes, coughs, drools, spits or talks excitedly, his or her infected fluids will be trapped in the mask and will not infect others.
This is about the best you can expect from masks...N99 are slightly better but twice the expense.
"The question about how the flu virus is spread is highly controversial, said Dr. Trish Perl, senior epidemiologist for Johns Hopkins Medicine, who is conducting a separate study on reducing the flu's spread through better-made face masks.
Preventive flu protocol is based largely on studies from the 1930s and '50s that found the virus is spread by direct and indirect contact, Perl said. The belief has been questioned in recent years, but not enough studies have been conducted to support any kind of change, Perl said."
Comment on droplet sizes:
"... some as small as 50 nanometres, taken from a person's breathing, coughing and sneezing."
The flu virus is about 80 to 120 nanometres in diameter. Tests on N95 masks have shown they are at least 95% efficient at removing common table salt particles with sizes of between 100 to 300 nanometres. Tests with Mycobacterium tuberculosis showed filtration efficiencies of 99.5% or higher. No doubt with the mask properly fitted!!!
Hi , like Newdawn I have never seen anyone here in South Wales wearing a face mask, hard enough for most to use the gel in the Doctor's surgery. I have just returned from a Christmas shopping expedition, so have settled for yet another hand wash and a squirt of first defence, in the hope that any bugs I might have picked up will be terminated.
Professor Raina MacIntyre, Head of the School of Public Health and Community Medicine at UNSW, Australia has provided excellent advice on wearing face masks and other methods of infection protection here:
N95 masks, on the other hand, were 56% effective against lab-confirmed respiratory viral infections and 75% protective against confirmed influenza. The fitted N95 masks didn't appear to provide more protection than unfitted N95 masks.
Medscape article on Professor MacIntyre's mask protection research
A Cluster Randomized Clinical Trial Comparing Fit-tested and Non-fit-tested N95 Respirators to Medical Masks to Prevent Respiratory Virus Infection in Health Care Workers. Link is to the discussion page:
From Raina MacIntyre's response to comments on a MERS Coronavirus article she wrote, she received quite a lot of flack for her research on the efficacy of N95 masks for health care workers - particularly from the USA:
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