Studies show that even a simple surgical mask effectively reduces SARS-CoV-2 infection

“Don’t forget your mask”-Most people today follow this advice, but experts have expressed different opinions about the effectiveness of face masks. An international team led by researchers at the Maxplank Institute of Chemistry in Mainz, Germany, is currently using observational data and model calculations to answer unanswered questions.

This study shows how masks actually help reduce the average risk of individuals and populations infected with COVID-19 and alleviate the corona pandemic under what conditions. In most environments and situations, even a simple surgical mask effectively reduces SARS-CoV-2 infection and effective regeneration of COVID-19.

However, in environments where the virus concentration in the air may be high, such as in medical settings or in dense indoor spaces, it is necessary to use a mask with high filtration efficiency (N95 / FFP2) and combine it with other protective measures such as centralized ventilation. there is.

Face masks are one of the simplest, easiest to use and effective countermeasures against aerial transmission of infectious respiratory diseases, but their usefulness for COVID-19 is still under debate. Several previous studies have found that masks are clearly ineffective under certain conditions. Others have found high efficiency, but have not been given a definitive explanation for the obvious contradictions and contradictions.

Researchers at the Max Planck Institute for Chemistry (MPIC), Johannes Gutenberg University Mainz Medical Center, and Charité-Universitätsmedizin Berlin have worked with partners in China and the United States to elucidate using observational data and a new quantitative model of aerial virus exposure.How Effectiveness of Face masks rely on a characteristic regime of airborne virus levels.

In most cases, even a simple surgical mask will work

In the case of SARS-CoV-2 aerial transmission, it is usually found that a small portion of the exhaled respiratory particles contain the virus. Most environments and contacts are under virus-restricted conditions, and face masks, including simple surgical masks, are highly effective in preventing the spread of COVID-19. Our study provides a detailed and novel understanding of the effectiveness of population average masks. This explains why areas with a high proportion of people wearing masks manage their pandemics better... “

Yafan Chen, Head of Minerva Research Group, Max Planck Institute for Chemistry

However, in indoor environments rich in potentially infectious viruses, more advanced masks (N95 / FFP2) and other protective equipment are required to prevent airborne transmission. The strong reliance on the virus concentration in the air for the effectiveness of the mask highlights the importance of combining the mask with other protective measures such as ventilation and distance to keep the chances of infection low.

“The combination of high-efficiency masks and other protective measures is especially important for hospitals, medical centers, and other indoor environments where high-risk patients may encounter high levels of the virus,” Charite’s respiratory system. Christian Witt, head of the research area, said. –Universitätsmedizin Berlin. “Masks continue to be an important protective measure against SARS-Cov-2 infection, especially in vaccinated individuals, especially if the protection provided by vaccination diminishes over time.”

This approach can be used to assess protection against more infectious mutants

“Our approach and results of associating the effectiveness of protective measures with infection probability and basic reproduction number can be applied to a variety of respiratory viruses and illnesses, including coronavirus, rhinovirus, and influenza. These are SARS. -Masks and other precautions against new and more infectious variants of CoV-2, says Hang Su, MPIC research group leader. “Our research also shows that aerosol infections do not necessarily lead to very high reproduction numbers, as observed in measles, and that relatively low reproduction numbers do not rule out aerial transmission. “

In addition, this study shows how important mask compliance and correct use are to ensure the effect of reducing the number of COVID-19 reproductions. Surgical masks require at least 60-70% compliance (approximately 40% for N95 / FFP2 masks) to reduce the number of reproductions from the initially observed 3 to less than 1.

More infectious variants of SARS-CoV-2 require higher compliance rates and other protective measures such as ventilation and distance to masks to effectively reduce infection probability and reproduction numbers. Reemphasize that it needs to be combined with.

“Our study quantitatively explains why and how face masks are very effective in virus-restricted environments and less effective in virus-rich environments-observed infection rates. And at the average level of individuals and populations associated with effective reproduction numbers. The mechanism insights and quantitative results obtained in our study resolved the ongoing debate about the usefulness of masks. We are confident that it will form a scientific breakthrough that will help facilitate. Efficient mitigation of COVID pandemics, “concludes Ulrich Pöschl, director of the MPIC Polyphase Chemistry Division.