Just to let people know, any face mask/filtration is better than none. In countries where there are adequate face masks or shortage is not severe, the recommendation from their gov is for public to wear face masks. Only in countries where face masks and respirators are severely lacking, the gov recommends for the public not to wear face masks.
The US Surgeon General and also US CDC revised its guideline a few weeks ago to tell people that are not healthcare workers to not wear face masks claiming it is useless for prevention and actually increases chances of transmission and all we need to do for prevention is to frequently wash our hands with soap. One of their justifications for this official guideline is because of their claim that COVID-19 is not airborne, which has already been proven untrue by experts in the US and China.
But if you think about it, the whole logic behind this revision to the guideline doesn’t make sense. They are saying common people should not wear mask because it is not effective and we need to save it for our health care workers. Why is it effective only for our health care workers in preventing transmission but not effective for ordinary people??
Given the CDC’s recent extremely poor credibility in topics related to COVID-19, we can easily see that the reason they are telling lies that wearing facemask is not effective and can even increase transmission is simply scare tactics to prevent common people from buying up respiratory protection. Though I don’t blame CDC since they are lying with good intention because we need to give our healthcare workers first priority. But the truth is any mask is better than no mask.
“The federal government’s Strategic National Stockpile of medical supplies includes 12 million medical-grade N95 masks and 30 million surgical masks — only about one percent of the 3.5 billion that the Department of Health and Human Services estimates would be needed over the course of a year if the outbreak reaches pandemic levels.”
Per NYTimes, “the vice president has called on construction companies to donate masks, the surgeon general has urged the public to stop buying them, and experts have warned that, the more doctors and nurses who get sick, the greater strain on a system already stretched thin… Now, doctors, nurses and others are rallying on social media… that members of the public reach out to a nearby hospital if they had masks or other medical equipment to donate”
This study reported no significant difference in the effectiveness of medical face masks vs. N95 respirators for prevention of influenza or other viral respiratory illness.
Another study posted on CDC says, “Results of our study have global relevance to respiratory disease control planning, especially with regard to home care. During an influenza pandemic, supplies of antiviral drugs may be limited, and there will be unavoidable delays in the production of a matched pandemic vaccine (31). For new or emerging respiratory virus infections, no pharmaceutical interventions may be available. Even with seasonal influenza, widespread oseltamivir resistance in influenza virus A (H1N1) strains have recently been reported (32). Masks may therefore play an important role in reducing transmission.”
https://wwwnc.cdc.gov/eid/article/15/2/08-1167_article
CDC says, “A surgical mask or fit-tested respirator should be worn by healthcare personnel who are within 6 feet of a suspected or laboratory-confirmed influenza patient. A respirator can be selected when antiviral medication supplies are expected to be limited and influenza vaccine is not available, e.g., during a pandemic”
CDC says, “HCP should don a facemask when entering the room of a patient with suspected or confirmed influenza. Remove the facemask when leaving the patient’s room, dispose of the facemask in a waste container, and perform hand hygiene.”
In the most recent updated official guidelines for dealing with mask shortages, the CDC now even recommends that medical professionals “might use homemade masks (e.g., bandana, scarf) for care of patients with COVID-19 as a last resort” if other equipment is not available.
This compares the filtration performance of the different surgical masks and N95 respirator. The N95 is superior no doubt and has tighter fit so it should definitely be required for health care personnel exposed to high viral concentrations. But surgical mask will also help especially for common people. My guess is that any mask is better than nothing if it can filter out particulate matter and aerosols that viruses are attached to thereby “reducing” the virus concentration entering our lungs. At 0.1 micron, this already exceeds HEPA filtration levels, which makes it very effective against particulate matter and atmospheric aerosol.
https://www.crosstex.com/sites/default/files/public/educational-resources/products-literature/guide20to20face20mask20selection20and20use20-202017.pdf