Using a cloth mask over a surgical mask or using a mask brace to improve the fit of the mask strengthens the protective efficiency of face masks against respiratory aerosols, according to a new study reported in the American Journal of Infection Control. 

The efficiency of different types of face masks against respiratory aerosols were evaluated in human participants as well as in simulator manikins. The study was conducted between January 2021 and April 2021. The face masks studied included two medical masks and three cloth masks of different material (polyester blend or cotton) and ply. The study also assessed the impact of combinations of masks and modifications of masks. A mask bracket, an ear loop strap, ear loop toggles and a mask brace were used to improve fitting of the mask. Double masking (wearing a 3-ply cloth mask over a medical face mask), crossing the ear loops and knotting & tucking were the other methods used to adjust the fit of the mask.

Results showed that medical masks alone without any modifications blocked ≥56% of cough aerosols and ≥42% of exhaled aerosols. Crossing the ear loops or placing a bracket under the mask had no effect on the efficiency of the mask, but use of ear loop toggles/straps, knotting and tucking the mask augmented mask efficiency.

Double masking blocked ≥85% of cough aerosols and ≥91% of exhaled aerosols, while using an elastic brace to fix the mask stopped ≥95% of cough aerosols and ≥99% of exhaled aerosols by better sealing of the gap and preventing leakage.

Correct and consistent use of a 3-layer mask is an essential public health measure to prevent Covid-19. The CDC recommends that “masks should completely cover the nose and mouth and fit snugly against the sides of the face without gaps”.

This study has shown that the efficacy of masks depends not just on the filtration efficiency but also on how well it fits the person wearing the mask. An ill-fitting mask is ineffective in preventing spread of infection. A loose mask allows respiratory aerosols to escape through the gap between the mask and the face rather than passing through the filter. It further demonstrated that combination of masks and using aids to ensure a tight fitting face mask also enhanced the protection. By creating a better seal, double masking and a mask brace were determined to be most effective in protecting against respiratory aerosols as well as reducing their expulsion, in this study.

With the emergence of the highly transmissible Omicron variant and the rapidity of its spread plus immune evading behavior, adherence to Covid-appropriate behavior becomes imperative. The Omicron cases in India have crossed the 100 mark. The possibility of a third wave may well become a reality if prevention measures are not followed. Avoid all non-essential travel, avoid mass gatherings, regularly wash hands with soap and water (or use a hand sanitiser) and double mask (with well-fitting masks) when in public places.

So, protect yourself and at the same time protect others too.

Reference

1. Blachere FM, et al. Face mask fit modifications that improve source control performance. American Journal of Infection Control. December 15, 2021. DOI: https://doi.org/10.1016/j.ajic.2021.10.041.