Letter to the Editor: "Asymptomatic Carrier Transmission of Coronavirus Disease 2019 (COVID-19) and Multipoint Aerosol Sampling to Assess Risks in the Operating Room During a Pandemic".

Letter:

The novel coronavirus disease 2019 (COVID-19) causing acute infectious pneumonia has widely spread in China and other countries around the world. Globally, as of 5:01 pm Central European Summer Time, July 18, 2020, there have been 13,876,441 confirmed cases of COVID-19, including 593,087 deaths, reported to the World Health Organization. Studies have documented that the novel coronavirus spreads through human-to-human transmission in hospital and family settings. , Nevertheless, the transmission of the novel coronavirus from an asymptomatic carrier should be considered as a source of the infection of COVID-19 as well. It has been demonstrated that viral load detected in asymptomatic patients was comparable with that in symptomatic patients, suggesting the transmission potential of asymptomatic or minimally symptomatic patients. Therefore, it is of significance to identify and isolate asymptomatic carriers as well as patients with mild symptoms to prevent the spread of the virus.

To achieve this, asymptomatic patients have been compiled in the daily report and released by the government of the People's Republic of China from April 1, 2020. However, attention was paid insufficiently to this aspect in other regions, including the United States and Europe. Currently, China has lifted coronavirus restrictions, and some of the European countries have also started to ease lockdowns from mid-May 2020. We should be on alert for a potential second wave of infections from the massive movement after lockdown ease, owing to the certain level of infectivity of asymptomatic carriers. Since the resurgence in contagion could be possible as late as 2024, early identification of asymptomatic carriers may become the key to prevent the spread of coronavirus.

Yu et al. found that aerosols carrying the severe acute respiratory syndrome (SARS) coronavirus may spread from a common source to buildings remote from the index patient in the investigation of the distribution of SARS cases in the Amoy Gardens outbreak. Considering that the sequence similarity between SARS coronavirus 2 and SARS coronavirus is as high as 85%, we should be alert that the course, transmission, and prognosis of COVID-19 pneumonia may follow the same trend as patients with SARS. Wax and Christian reported that due to medical procedures that may produce aerosols, the Public Health Agency of Canada guidelines support the airborne isolation of patients with suspected or confirmed COVID-19. Taking into account the characteristics of aerosols, these also mean that the virus is no longer transmitted only through the air. After the physical decay of the virus-laden aerosol plume, the mode of exposure could still be contact with inanimate materials or objects contaminated by the infection-competent virus.

Bioaerosol studies have shown the risk of airborne and droplet transmission of respiratory viruses in buses, aircraft cabins, and cities. Coleman et al. reported that bioaerosol sampling may have practical value in detecting respiratory viruses in public places, as bioaerosol sampling provides a noninvasive way to monitor and characterize aerosolized respiratory virus communities that regularly infect the public, and potentially detect or discover new pathogens with pandemic potential. We believe that when used in combination with molecular diagnostic technology, aerosol sampling is expected to serve as a noninvasive tool to monitor SARS coronavirus 2 in the operating room. In addition, in the stages of a pandemic, the availability of aerosol sampling in the operating room is important, to encourage analytical efforts by independent teams and provide robust evidence to guide interventions.