A new study by the University of Maryland School of Public Health has shown that COVID-19-infected people exhale infectious viruses in their blood. Those infected in the Alpha variant of the virus (which is the dominant strain at the time of this study) released 43 to 100 times as much virus into the air as those infected in the original strains. Researchers also discovered that surgical masks and loose-fitting cloth reduced the amount virus in the air around people with the disease by half. Clinical Infectious Diseases published the study.
Professor of Environmental Health at the University of Maryland School of Public Health, Dr. Don Milton said that "our latest study further supports the importance of airborne transmitting." We know that the Delta variant is more contagious now than the Alpha variant. Research has shown that the virus is more easily spread through air than ever before. To stop the spread of the virus, we need to improve ventilation and use tight-fitting masks.
Alpha variant infection caused 18 times more virus to enter the air than can be explained by increased virus levels in saliva and nasal swabs. Jianyu Lai, a doctoral student, explained that the virus levels in nasal swabs and saliva were higher in Alpha variant infections. Sprays of large droplets close to infected people could transmit virus from the nose or mouth. Our study has shown that the virus in exhaled aerosols increases even more. These significant increases in the incidence of airborne viruses from Alpha infections were seen before the arrival of the Delta variant. This suggests that the virus is improving its ability to travel through the air.
This study tested whether facial masks can prevent the virus from spreading among people. It measured the amount of SARS-CoV-2 that was inhaled into the atmosphere and then tested the effect on the virus exhalation by people with COVID-19. The presence of virus-laden particles in the air around a person suffering from COVID-19 was reduced by 50% using face coverings. However, even surgical masks and loose-fitting clothing didn't prevent infectious virus from entering the air.
Dr. Jennifer German, co-author, stated that "the coronavirus can still be in your exhaled air, is improving at being in exhaled breathe, and wearing a mask decreases the risk of it inhaling on other people." To protect those in public spaces and jobs that require ventilation, a multilayered approach to controlling the virus (including increased filtration, UV sanitation, improved ventilation and tight-fitting masks) is essential.
Researchers from Rice University, University of Maryland School of Public Health and University of Maryland School of Medicine conducted the study Infectious SARS CoV-2 in Exhaled Airsols and Efficacy of Masks during Early Mild Infection.