The novel coronavirus can travel up to 13 feet or 4 meters from patients in hospital wards, a new study has found. This is twice the distance current guidelines recommend for social distancing.
A team of researchers from China published their preliminary results in the Emerging Infectious Diseases, a journal of the U.S. Centers for Disease Control and Prevention (CDC). The team conducted the study to determine the distribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in hospital wards in Wuhan City, China, where the novel coronavirus first emerged. They tested air and surface samples and found that the contamination was more significant in intensive care units than general wards.
Further, evidence suggests that the virus was widely distributed on floors, trash cans, computers, and sickbed handrails, and in the air within 13 feet from patients. With this widespread of the virus, health workers are in danger of contracting the virus and getting ill.
The coronavirus disease has now spread to 185 countries and territories, infecting nearly 2 million people and killing more than 126,000. The United States has the most significant number of infections, with the case toll reaching more than 608,000 people and the death toll nearing 26,000.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, can spread through respiratory droplets and close contact. The CDC and WHO guidelines say to practice social distancing of about 6 feet or 2 meters to prevent contracting the virus.
“Knowing the extent of environmental contamination of SARS-CoV-2 in COVID-19 wards is critical for improving safety practices for medical staff and answering questions about SARS-CoV-2 transmission among the public. However, whether SARS-CoV-2 can be transmitted by aerosols remains controversial, and the exposure risk for close contacts has not been systematically evaluated,” the researchers wrote on the paper.
While the findings of the study do not indicate the amount of live virus, if there is any, the researchers say that they confirm that the virus spreads in aerosols, in addition to large respiratory droplets.
To arrive at their study findings, the team collected swab samples from potentially contaminated objects in the ICU and general ward of a Wuhan City hospital between Feb. 19 and Mar. 2. There were 24 patients admitted in the general ward, while 15 patients stayed in the ICU. The team also collected air samples by using a SASS 2300 Wetted Wall Cyclone Sampler at 300L/min for 30 minutes.
The everyday objects in the ward where samples were collected include patient masks, personal protective equipment (PPE), computer equipment, sickbed handrails, trash cans, and air outlets. The rate of positivity of virus contamination is high for the surface of objects commonly touched by the medical staff, such as the computer mouse, followed by the trash cans, sickbed handrails, and doorknobs. Also, viral particles were found in sleeve cuffs and gloves of medical staff, hinting the importance of practicing hand hygiene every after patient contact.
Patient masks also contain exhaled droplets and oral secretions, and the team recommends that it should be disinfected before discarding them.
The team found that most of the contamination occurs in the ICU, compared to the general ward. About 35 percent of the air samples from the ICU tested positive for coronavirus, while only 12.5 percent were positive in the general ward. In air vent swabs, 66.7 percent tested positive in the ICU, while 8.3 percent in the general ward.
The results of the study show how important it is to practice strict disinfection in the hospital, and health workers should be very vigilant in protecting themselves, especially those in the ICUs.
Further results show that in terms of aerosol transmission, the virus-laden aerosols were concentrated near and downstream from patients at up to 13 feet, while smaller quantities were found upstream, up to eight feet.
“The study has three conclusions. First, SARS-CoV-2 was widely distributed in the air and on object surfaces in both the ICU and GW, implying a potentially high infection risk for medical staff and other close contacts. Second, the environmental contamination was greater in the ICU than in the GW; thus, stricter protective measures should be taken by medical staff working in the ICU. Third, the SARS-CoV-2 aerosol distribution characteristics in the GW indicate that the transmission distance of SARS-CoV-2 might be 4 meters,” the team concluded in the study.
- Guo, Z.D., Wang, Z.I., Zhang, S.F., Li, X., Li, L., Li, C., Cui Y. et al. (2020). Aerosol and Surface Distribution of Severe Acute Respiratory Syndrome Coronavirus 2 in Hospital Wards, Wuhan, China, 2020. Emerging Infectious Diseases. https://wwwnc.cdc.gov/eid/article/26/7/20-0885_article