Becker's Clinical Quality & Infection Control

7 INFECTION CONTROL COVID-19 variants travel farther in the air, studies suggest By Erica Carbajal T he virus that causes COVID-19 has evolved to become more airborne, a possible explanation as to why variants like alpha and delta are more transmissible than the original strain, The New York Times reported Oct. 1. While researchers have already established that COVID-19 is mostly spread by coming into contact with large respiratory droplets and aerosols that trav- el through the air, two new findings indicate the virus has evolved to become more efficient at airborne travel. In the first study, published in the preprint server bioRxiv, researchers found small aerosols travel much farther than large droplets and that the alpha variant was much more likely to spread through the air. A separate study published in Clinical Infectious Diseases Sept. 14 also focused on alpha. It found people infected with the strain exhale about 43 times more virus in small aerosols compared to those infected with earlier strains. Scientists on this study concluded, "SARS-CoV-2 is evolving toward more efficient aerosol generation and loose-fitting masks provide significant but only modest source control. Therefore, until vaccination rates are very high, continued layered controls and tight-fitting masks and respirators will be necessary." While both of the studies focused on alpha, the findings may also reveal why delta is so transmissible. "It really indicates that the virus is evolving to become more efficient at trans- mitting through the air," Linsey Marr, PhD, an airborne virus expert at Virginia Tech in Blacksburg, told the Times. "I wouldn't be surprised if, with delta, that factor were even higher." Dr. Marr was not involved in the two studies. n Support for flu shot mandates fell during pandemic, survey finds By Mackenzie Bean T he public's support for workplace flu shot mandates has decreased since 2019, according to an Oct. 25 survey from ValuePenguin, a financial research and analysis website. The online survey, fielded Sept. 23-30, included responses from a nation- ally representative sample of 2,050 Americans. Forty percent of respondents supported workplace flu shot requirements, down from 55 percent in October 2019, the last time ValuePenguin fielded this survey. Fewer people also reported plans to get the flu shot this season. Fif- ty-three percent of respondents said they already received or planned to get a flu shot, down from 57 percent who said the same in 2019. Thirty-six percent said they would not get the flu shot this season. n Breakthrough infections may not pose major transmission risk, immunologists say By Erica Carbajal T he virus shedding from people with break- through COVID-19 infections may be less infectious than that coming from an unvac- cinated COVID-19 patient, NPR reported Oct. 12. Immunologists said preliminary research has indi- cated the virus coming from an infected vaccinated person is less infectious because it's coated with antibodies generated from vaccination. While the antibodies don't necessarily prevent infection, they still "should be coating that virus with antibody and therefore helping prevent excessive down- stream transmission," Ross Kedl, PhD, an immu- nologist at the University of Colorado School of Medicine in Aurora, told NPR. e news outlet cited a study of breakthrough infections among healthcare workers in Israel that found for all 37 case patients where data on the source of infection was available, the sus- pected source was an unvaccinated person with COVID-19. While the Pfizer and Moderna mRNA COVID-19 vaccines are injected into the arm muscle and generally expected to generate only the kinds of antibodies that circulate throughout the body, findings published Aug. 30 in the preprint server medRxiv showed antibodies also showed up in mucosal membranes. "is is the first example where we can show that a local mucosal immune response is made, even though the person got the vaccine in an intramus- cular delivery," said Jennifer Gommerman, PhD, an immunologist at the University of Toronto who was involved in the research. In July, a CDC report made headlines aer it found 74 percent of people who contracted COVID-19 aer a number of large gatherings in Barnstable County, Mass., were vaccinated. However, Dr. Kedl said it's difficult to confirm whether the majority of these breakthrough cases were spread between vaccinated people. "In all these cases where you have these big break- through infections, there's always unvaccinated people in the room," he told NPR. n

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