Masking, Bacteria, and Fungus
Analyzing the recent mask study from Japan, and seeing what can grown on your masks.
Well, it seems like the paranoia and mask-clutching zealots are at it again. Many places within California such as San Diego and Los Angeles have started to reimplement mask mandates. Some national parks have brought back indoor mask mandates as well. Now, I’m not sure where exactly the indoors are in national parks, but it’s the middle of summer, and a time when people should be outdoors and getting as much sunlight as possible (with protection, mind you) and not be cooped up inside.
And to be frank, there really was no effective study on masking to begin with. It was a heavily precarious policy that validated itself through circumstantial evidence. Everyone was forced to wear a mask, and if the cases so happened to fall it was proof of the masks’ effectiveness. And thus, the recursive loop of masking was validated.
As indicated in the Reason article from above, many talking heads on CNN and the CDC’s own Director Rochelle Walensky have made similar sentiments in regards to the general ineffectiveness of masks:
Wearing masks might provide some marginal protection against COVID infection, but even that's pretty debatable. The Centers for Disease Control and Prevention (CDC) admitted in January that nonsurgical masks provide little protection. "Cloth masks are little more than facial decorations," is how CNN medical analyst Leana Wen described them in December 2021. Fitted surgical masks and N95 masks provide better defense but are cumbersome to wear on a regular basis, as even CDC Director Rochelle Walensky has conceded.
There's less debate about the effectiveness of mask mandates, which are mostly about virtue signaling and don't seem to accomplish much—other than usefully demonstrating the hypocrisy of public officials caught flouting their own masking orders. "We do not find evidence that mandating mask-wearing reduces transmission," a group of Yale University researchers reported in June of last year. "Our results suggest that mask-wearing is strongly affected by factors other than mandates."
During last fall's surge in COVID cases, the "states with mask mandates haven't fared significantly better than the 35 states that didn't impose them," science journalist Faye Flam wrote in a Bloomberg Opinion essay. "There's little evidence that mask mandates are the primary reason the pandemic waves eventually fall—though much of the outrage over lifting mandates is based on that assumption."
Personally, I am of the belief people can choose to wear a mask (or not) if they so please, which is entirely different than being forced/mandated to wear one by people who never provide robust evidence in support of such mandates.
So why all of the fuss over something that has never been critically substantiated through rigorous, scientific means?
Generally, we work off of the paradigm of “safe and effective”. The measures and therapeutics taken should be effective at doing what is intended to do, while also having few side effects or possible adverse reactions.
Masks have generally failed on the “effective” argument, but what about the safety argument?
A recent study came out from Japan which may shed some light on the matter.
Masking and bacterial/fungal growth
This study (Park, et. al.1) was brought to my attention from Jeff Child’s Coffee & COVID post. I read the post and made a few quips about the masking study- without having read it yet myself (I should try not to do that).
It’s an interesting study, because it is one of the first of its kind in which researchers wanted to see what may grow on masks after use.
For this study, researchers looked at 3 different types of masks (none of them N95 or higher) and wanted to see what bacteria and fungi may grow on the masks (emphasis mine):
Three types of face masks are commercially available for daily lives in Japan: (1) non-woven, (2) polyurethane, and (3) gauze or cloth masks (Fig. 1a,b). Non-woven masks are commonly used worldwide to prevent droplet infections by most respiratory microbes, including SARS-CoV-2 (Fig. 1c). Polyurethane masks have been used to protect against hay fever, particularly in Asian countries. Since polyurethane masks are easy to breathe and washable, the masks have become popular and have been reused several times during the COVID-19 pandemic. Although gauze masks are less popular, the masks can be washed, reused, and effectively prevent infections. Thus, the Japanese government distributed gauze masks to all citizens because of the shortage of non-woven masks during the early stage of the COVID-19 pandemic.
Non-woven are generally the “surgical masks” that you see in abundance everywhere and are the ones you have likely used the most (look at Fig. 1.a for representations of each mask).
So unlike prior studies, this study wanted to look more closely into the hygienic nature of continuous mask wearing:
Although the effectiveness of face masks against viral transmission has been extensively studied3,4, the hygiene issues in mask usage remain unclear. The standard mask usage is disposable non-woven masks. In some cases, however, people may use non-woven masks repeatedly or use different types of masks in different situations depending on their socioeconomic cultures. For example, in Japan, the short supply of non-woven masks led to the repeated use of disposable non-woven masks and the use of other types of face masks, such as handmade masks and polyurethane masks6. Even after the shortage of mask supply has been resolved, some people have used disposable non-woven masks repeatedly or other types of face masks.
I generally disagree with the first remark, although we have to keep in mind that this study was conducted around 2020 so it may just reflect the information available at the time (as little and as flimsy as the data was).
The study contained 109 Japanese medical students and stratified the microbial growth based on variables such as days same masks were worn (up to 3 days), gender, route of transportation, and even behaviors such as gargling and consumption of fermented foods.
In order to incubate mold and bacteria, the researchers collected each participant’s masks and pressed them onto an agar plate and left them to incubate. This was done for both the outside and inside (portion facing the face) of the mask. After a few days the researchers looked at the colony morphologies and collected data on which fungi and bacteria grew.
Results
Bacterial Growth
The results here are pretty interesting. In general, there were higher levels of bacteria on the inside/face-side of the mask. More interesting, continuously wearing the same face mask did not significantly increase bacteria levels over time.
The researchers make the following remarks in regard to the types of masks worn:
To evaluate the influence of the mask types and duration of mask usage, we compared the colony counts among those who used the mask for one day (3–6 h), two days, and longer based on the mask types [non-woven, others, and all (non-woven and others combined)]. We found no significant differences in the colony counts among the different mask types, regardless of the duration of usage.
We may assume that continuous mask-wearing would drastically increase the number of bacteria on a given mask. The researchers provide a possible explanation for the results, suggesting that air-drying the masks may allow time for the bacteria to die off before the next use:
Although we anticipated that the counts of bacterial colonies could increase due to the duration of mask usage, this was not the case. The moisture requirement of bacteria may explain this20,21. While we wear a face mask, the humidity under the mask space becomes approximately 80%, in which bacteria can survive and grow22,23. In contrast, when a used mask is not worn for a long time, particularly at night, it dries out overnight and bacteria on the mask are likely to die due to the dry conditions.
The important factor here is whether the bacteria that accumulated could be pathogenic and dangerous. Fortunately, it appears that most of the bacteria are not pathogenic, and most are found either within our respiratory tract or on our skin microbiome.
However, just because these bacteria are part of our microbiome doesn’t necessarily mean that we are fully protected from infections. For example, Staphylococcus epidermidis and Staphylococcus aureus are classified as pathobionts (symbiotic bacteria that may become pathogenic under certain circumstances). These bacteria are part of our microbiome and generally kept in check. However, if levels of these bacteria increase above normal levels they can lead to various skin conditions2.
You may have heard the term “maskne” thrown around after many people began reporting on breakouts after wearing masks, and it’s likely because of these bacteria growing in larger numbers than they would otherwise normally grow.
So although several of these bacteria are ones generally found within our own body and on our skin, masking may create a hospitable environment for them to grow, leading to breakouts and other possible issues.
As an aside, the researchers made an assumption that bacterial growth would be higher for men than women. Now, I’m sure there’s such a thing as “man-breath”, but it’s interesting that such an assumption was made.
In reality, the researchers wanted to see if skincare products (which I suppose may indicate higher hygienic practices, or possible antimicrobial compounds in the products) would lead to lower levels of bacteria growth, and that appears to be the case (Supplementary Figure 33; not shown), with the authors suggesting the following:
The proportion of variance of principal component (PC) 1 was 44%; PC1 values reflected more intensive facial skincare. Here, the bacterial colony numbers and three skincare categories contributed negatively and positively to PC1 values, respectively. This suggested that more intensive facial skincare may decrease bacteria on the face masks. Among the three skincare categories in the survey, we tested whether the foundation usage could affect the number of bacterial colonies. We recruited volunteers and asked them to wear the mask for 4 h with foundation applied to only the left half of their faces. We found no differences in the bacterial colony numbers between the left and right halves of the face masks (Fig. S3b). Furthermore, neither lotion/sunscreen usage nor the face wash method statistically decreased the bacterial colony numbers by itself (data not shown). Although we did not examine other factors that may contribute to the gender difference in the bacterial colony counts, the potential factors include the higher facial temperature in males24 and the gender difference in sweat and sebum25.
Fungal Growth
Unlike the bacteria section, the fungal growth isn’t quite as exciting. In general, fungi tended to accumulate on the outside of the mask compared to the inside of the mask. This may allude to the fact that mold spores are much larger, and thus may have more difficulty passing through the mask. However, there are strange inconsistencies with the results, such as the higher level of fungi on day two that appears to decline on day 3. This could be due to sample collection and differences in time of mask wearing (this study was likely conducted over many days so that participants can wear masks for 2 days and sacrifice them, then wear masks for 3 days to get the two categories).
The researchers provide these remarks:
The colony counts of fungi were fewer than those of bacteria and the colony counts on the face-side and outer-side were 4.6 ± 1.9 and 6.1 ± 1.9 (mean ± SEM), respectively. In contrast to the bacterial colonies, the fungal colony counts in each individual were 2.4-times higher on the outer-side than on the face-side (paired t-test, P < 0.05). When the participants used the same masks for more than two days, the fungal colony counts were increased on the outer-side of masks, compared with the one-day usage. There were no statistical differences in the colony counts between non-woven and “others” mask users except for the fungal colony counts of the outer-side of masks after one-day usage.
In short, fungi was seen more predominately on the outside of the masks, and fungal colonies were magnitudes lower than those found with bacteria colonies. However, unlike repeat wearing and bacterial growth, fungi continued to accumulate over repeat wearing. This is likely because spores are more resilient to environmental changes, and thus they can live longer on the mask compared to bacteria (emphasis mine):
On the other hand, since fungi and their spores are resistant to drying, they can survive under the condition where masks dry out. This explains why fungi tended to accumulate and increase with longer mask usage. When we compared the microbial colony counts between the mask types, there were no substantial differences in the microbial colony counts between non-woven and other mask types. These findings suggest that the higher fungal colony counts on the outer-side of masks would be due to the duration of mask usage, but not the mask types.
That leaves us with figuring out whether the fungi are pathogenic. It appears that a few of them are, and only one (Aspergillus) appears to come from an indoor setting.
Is this cause for concern? It’s difficult to figure out, mostly because the researchers did not differentiate which fungi grew from which side of the mask, and so there’s no indication as to whether the pathogenic fungi may reside on the inside portion of the mask.
The researchers do mention that many of the fungi are opportunistic, and because more fungus accumulate on the outside and over repeat use, it’s likely to be a far easier issue to deal with through proper sanitizing of masks or through disposal after a few hours of use.
In short, unlike the results with bacteria the fungus results may not be too concerning. Greater accumulation on the outside of the masks would indicate that the spores may not be penetrating the masks, and thus may not be breathed in to such a high degree. These are generally issues that could be dealt with through proper hygiene and mask disposal.
“Safety” in Masking
This study is one of the only studies available that actually looked at the hygienic nature of mask-wearing. In a time where mask mandates appear to be popping up once again, we need to make sure we have proper science to validate a need for such a draconian measure.
In this study, researchers did not look at the effectiveness of masks, but instead looked at what bacteria and fungi could accumulate- a possible safety signal.
For bacteria, many of the bacteria found were those located on our skin or within our respiratory tracts. However, the artificial environment created from masking may provide these bacteria opportunities to become pathogenic (pathobionts). This includes the possibility of skin infections via breakouts, or possible respiratory infections as well. Considering that bacteria accumulation is independent of repeat mask wearing4, and instead depends upon the duration of mask wearing, this should raise some concerns for masks that are worn throughout the entire day and not changed out or disposed of. In fact, the results from the bacteria colonies may raise concerns about mask wearing in general.
This is a big concern for students who may be forced to keep a mask on all day or be penalized by teachers and school staff. Messaging generally doesn’t explain that masks should be disposed of after several hours of use. The CDC’s own website does not explain what to do with disposable masks after a given time, but instead mentions that one should throw out disposable masks if they get wet or dirty (what constitutes dirty?)5. Remember that much of this comes on the heels of additional evidence that masking may not provide any protection in general for school children.6
The results on fungi are not as explicit, but they indicate that accumulation is likely to occur on the outside of the mask without possible penetration. Since fungi accumulation is dependent of repeat mask wearing, it makes sense to emphasize not wearing the same disposable mask continuously, or to make sure that cloth masks are washed properly (boiling water with detergent).
There are a few caveats to this study that should be emphasized. For one, the researchers never indicate which bacteria/fungi grew from which side of the mask. The data appears to be compiled together, and so one may infer based on the overall levels of bacteria/fungi on different sides of the mask. This is made even more difficult as there isn’t any indication as to whether certain bacteria may have a preference for different mask materials (as indicated within the Delanghe, et. al. study).
The level of mask wearing was also not fully explained, and there appears to only be a notation of one day being equivalent to 3-6 hours of mask wearing. Whether these hours are consistent over the course of 3 days was not explained, so there’s no indication as to the actual duration of mask wearing on any given day.
Lastly, the researchers never take into account behavioral factors, such as the frequency of mask-touching and how often masks were taken off. The researchers comment that one genus of bacteria found was one usually found in feces, and so it raises questions why researchers did not include this variable in their analysis:
We detected B. cereus, a foodborne pathogen, on the outer-side of masks in 5% of the participants (Fig. 4c), suggesting that B. cereus might adhere to the face masks through hands from feces. Intensive handwashing is recommended, since handwashing is effective in reducing the incidence of diarrhea19.
In general, this is a study that should have been conducted right from the start of the pandemic. As mask mandates began to emerge we needed robust evidence to either substantiate or refute such a need for draconian mandates, and yet no evidence was usually provided.
Here, the evidence suggests that there are viable, real-life concerns about possible bacterial infections from continuous mask wearing. For those who may be forced to wear a mask (or do so optionally) there should be greater emphasis on changing masks throughout the day.
Yet this is just another example of continuous measures that are considered to be ineffective, with additional evidence suggesting that these measures may be harmful.
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rk, AM., Khadka, S., Sato, F. et al. Bacterial and fungal isolation from face masks under the COVID-19 pandemic. Sci Rep 12, 11361 (2022). https://doi.org/10.1038/s41598-022-15409-x
Delanghe L, Cauwenberghs E, Spacova I, De Boeck I, Van Beeck W, Pepermans K, Claes I, Vandenheuvel D, Verhoeven V and Lebeer S (2021) Cotton and Surgical Face Masks in Community Settings: Bacterial Contamination and Face Mask Hygiene. Front. Med. 8:732047. doi: 10.3389/fmed.2021.732047
*This study is actually really interesting. I haven’t looked at it too extensively, but it compares cloth masks to surgical masks and looked at the bacteria that collected after use. Some of the bacteria incubated include some antibiotic resistant bacteria. There also appeared to be a preference for different masks based on the bacteria that grew.
This part of the study put foundation onto one side of a participant’s face. Interestingly, 6 of the participants were female and 3 were male.
This means that masking may lead to accumulation of bacteria throughout the day. However, this accumulation may not carry over to the next day. Essentially, the longer masks are worn the more concern that there may be increased risk of bacterial exposure, especially later in the day.
There is this completely ridiculous comment, in which children who may have difficulty breathing in an N95 mask should wear cloth or disposable masks. So on one hand they indicate that children may have difficulty breathing, while also saying that children should wear far inferior masks if they can’t breathe…
If your child has a hard time breathing, gets dizzy, or has other symptoms while you are trying to get the mask to fit better or when using an ASTM F3502 mask or a respirator, choose a cloth or disposable mask. They should continue to protect themselves and others. Consult your healthcare provider if these symptoms do not resolve.
Use of face masks did not impact COVID-19 incidence among 10–12-year-olds in Finland
Aapo Juutinen, Emmi Sarvikivi, Päivi Laukkanen-Nevala, Otto Helve
medRxiv 2022.04.04.22272833; doi: https://doi.org/10.1101/2022.04.04.22272833
This is a very small study that was conducted in a short window of time. The results here are extremely limited, but it at least adds to the mounting evidence against mask wearing in schools.
Is it a mandate? Yes, to a degree. So sue me, good luck. Is it a law? Nope.
Know your rights. My local bbfield states: social distance, mask up, it's the law! Actually it is not the law, how do you enforce social distancing, masking....it is all about Control. From your Local Beneficial Unnamed Bureaucrats.
I will not forget the takeaway here. 5% of people wearing masks are poo poo faces. Do not touch that nasty thing.