Effectiveness of Masks & Respirators at Preventing the Spread of COVID-19

Effectiveness of Masks & Respirators at Preventing the Spread of COVID-19

In a commentary that is almost a year old now but is quickly becoming more relevant again, a group of current and previous professors at the University of Minnesota’s Center for Infectious Disease Research and Policy discuss the effectiveness of masks and respirators in preventing the spread of COVID-19. 

The commentary sources data from various studies carried out in the first couple of years of the pandemic and exemplifies how masks are one of our best tools for preventing the spread of the virus. While the commentary covers a range of topics (and we recommend reading the whole commentary if you are interested), the most vital piece of information discussed is the effectiveness of different masking situations in stemming the spread of the disease.

The table below shows the time for an uninfected person to receive an infectious dose of COVID-19 from an infected individual. With a baseline of 15-minutes for the uninfected individual to become infected, we can see the increasingly long periods it takes when either or both individuals wear different types of masks.

Image source.


According to the quoted study, if either individual is wearing a typical cloth mask, it takes five extra minutes for the infected individual to spread COVID-19 to the uninfected individual. This shows the relative ineffectiveness that these non-fitted, low-filtration masks offer. 

If either party wears a surgical mask, the baseline length is doubled, taking an estimated 30 minutes for COVID to spread to the uninfected individual. While this is still a short period of time, it shows that even wearing a poorly-fitting surgical mask effectively doubles the time it takes for COVID-19 to spread.

The most interesting finding, however, is that an N95 (or similarly certified respirator) increases the time to an hour and twenty-five minutes if the respirator is non-fit tested and two and a half hours if the respirator is fit tested. This shows that even non-fit-tested respirators can perform very well.

However, these times are vastly increased when both individuals wear a mask. From 26 minutes with both individuals wearing cloth masks to 25 hours if both parties are wearing fit-tested N95 respirators, it is clear that the best way to prevent the spread of COVID-19 is to have everyone wearing masks.

While much information has been spread surrounding the effectiveness of masks at preventing the spread of COVID-19, none provides as stark of a picture as this study. The visualisation does a fantastic job of showing how effective masks are and why high-quality, high-filtration devices are essential.

We recommend checking out the full commentary here if you want to read more.

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