Written By: Satata Karmakar | Published : January 6, 2021 1:56 PM IST
Airborne transmission of COVID-19 virus possible in hospitals: Study
A new study by laboratories in Hyderabad and Mohali has found fresh evidence that the risk of airborne transmission of the novel coronavirus (COVID-19) is quite low ONLY if sufficient physical distance is maintained and prolonged interaction with an infected person is avoided.
A study by scientists at the CSIR at the Centre for Cellular & Molecular Biology (CCMB) indicates that the chance of picking up SARS-CoV-2 in the air is directly related to a number of COVID positive cases in the room, their symptomatic status, and the duration of exposure and that the demarcation of hospital areas into COVID and non-COVID areas is a successful strategy to prevent cross infections.
The two institutes on Tuesday released data on the air-borne nature of coronavirus, SARS-CoV-2. The data stated that:
- The virus was found in air samples from Covid-19 wards from hospitals but not from non-COVID-19 wards. This suggests that the demarcation of hospital zones has been an effective strategy.
- The studyalso showed the chances of picking up SARS-CoV-2 in the air is directly related to the number of Covid-19 positive cases in the room, their symptomatic status, and the duration of exposure."
According to the study - when Covid-19 individuals spent long hours in a room, the virus is found in the air for more than 2 hours even farther than 2 metres from their seating places. But for asymptomatic cases, they showed the virus does not spread farther from them when they are seated in a room without perceived airflow due to a fan or AC.
"Till the vaccines are available, the social vaccine that is wearing a mask is the best prevention," said Dr. Sanjeev Khosla, Director, IMTech.
Airborne transmission is defined as the spread of an infectious agent caused by the dissemination of droplet nuclei (aerosols) that remain infectious when suspended in the air over long distances and time. Airborne transmission of SARS-CoV-2 can occur during medical procedures that generate aerosols ("aerosol-generating procedures"). WHO, together with the scientific community, has been actively discussing and evaluating whether SARS-CoV-2 may also spread through aerosols in the absence of aerosol-generating procedures, particularly in indoor settings with poor ventilation.
Current evidence suggests that transmission of SARS-CoV-2 occurs primarily between people through direct, indirect, or close contact with infected people through infected secretions such as saliva and respiratory secretions, or through their respiratory droplets, which are expelled when an infected person coughs, sneezes, talks or sings.
The incubation period for COVID-19, which is the time between exposure to the virus (becoming infected) and symptom onset, is on average 5-6 days, however, can be up to 14 days. During this period, also known as the "pre-symptomatic" period, some infected persons can be contagious. Therefore, transmission from a pre-symptomatic case can occur before symptom onset.
All these findings do show that the coronavirus can stay in the air for some time. But they also strengthen the importance of Covid-19 preventive guidelines that we already have in place to curb this pandemic. If we ensure that we follow hygiene protocols such as regular hand washing, using masks effectively, and preventing symptomatic people from public mixing, we can start getting back to normalcy more comfortably. Detecting and isolating the positive cases early on can help prevent the spread among other family members in a home setting too. Also, wear a good quality mask whenever you step out of your house.
Fabric masks are recommended to prevent onward transmission in the general population in public areas, particularly where distancing is not possible, and in areas of community transmission. This could include the school grounds in some situations. Masks may help to protect others, because wearers may be infected before symptoms of illness appear. The policy on wearing a mask or face covering should be in line with national or local guidelines. Where used, masks should be worn, cared for, and disposed of properly.
