A recent article written by Will Chase for Axios discusses the need for better masks during the pandemic. Whether you are still masking or not, it’s important to have some masks on hand, and the article shows exactly how effective different kinds of masks are.
The article references a study from the Proceedings of the National Academy of Sciences, which compared the infection risk of two individuals (the infected and susceptible individual) wearing a range of different mask and respirator combinations.
In the study, FFP2 masks (which are referred to as N95 in the article) were compared to surgical masks. In the end, three different combinations were tested; both individuals wearing a surgical mask, both wearing an FFP2 respirator without a nosepiece, and both wearing an FFP2 respirator with a nose piece.
The results are fascinating - when both individuals wear surgical masks, there is a 10.4% infection risk for the susceptible individual after 20 minutes of speaking. With FFP2 respirators without a nosepiece, this chance drops to 4.2%. Finally, if both individuals wear an FFP2 respirator with a nosepiece, this drops greatly to only 0.14%.
This means it will take around 25 hours for an infectious dose of COVID-19 to transmit between the two if they are wearing non-fitted FFP2 (or equivalent) respirators. However, what’s truly amazing is that it takes around 2500 hours for an infectious dose to be transmitted with fit-tested respirators.
So, what can we conclude from this article? Well, surgical and poorly fitting masks decrease infection risk, but you still have a 4-10% chance of catching COVID in such a situation. An FFP2 or equivalent, on the other hand, drops this chance to below 1% - even after 20 minutes of talking.
As we’ve already seen ample evidence pointing to the efficacy of high-performance masks and respirators, these results are hardly a surprise. However, they do emphasise the need for high-quality respiratory protection.