- COVID-19 spreads between people through direct, indirect, close contact
- WHO acknowledged aerosol transmission in healthcare settings
- More research is required on transmission through aerosols: WHO
New Delhi: On Thursday (July 9), the World Health Organisation (WHO) shared an update to the scientific brief of March 29 entitled “Modes of transmission of virus causing COVID-19: Implications for infection prevention and control (IPC) precaution recommendations”. According to the new guidelines, airborne transmission of Coronavirus can occur in healthcare settings where specific medical procedures generate very small droplets – aerosols. However, more research is required on transmission routes and airborne transmission in the absence of aerosol generating procedures.
The new guidelines come days after 239 scientists from 32 countries wrote an open letter to WHO claiming airborne transmission of coronavirus beyond aerosol generating procedures. In an open-access article ‘It is time to address airborne transmission of COVID-19’ published in Oxford University Press for the Infectious Diseases Society of America, it’s stated, “Viruses are released during exhalation, talking, and coughing in micro-droplets small enough to remain aloft in air and pose a risk of exposure at distances beyond 1 to 2 m from an infected individual.”
Transmission Of Novel Coronavirus
In the scientific brief, WHO has talked about possible modes of transmission for SARS-CoV-2, including contact, droplet, airborne, fomite, fecal-oral, and others.
Transmission of SARS-CoV-2 can occur through direct, indirect (through contaminated objects or surfaces), or close contact with infected people through infected secretions such as saliva and respiratory secretions or their respiratory droplets, which are expelled when an infected person coughs, sneezes, talks or sings, says the WHO.
Apart from contact and droplet transmission, WHO acknowledged airborne transmission and reported outbreaks of COVID-19 in some closed settings, such as restaurants, nightclubs, places of worship or places of work where people maybe shouting, talking, or singing.
In these events, short-range aerosol transmission, particularly in specific indoor locations, such as crowded and inadequately ventilated spaces over a prolonged period of time with infected persons cannot be ruled out, said WHO.
The health organisation also noted that transmission of the virus could have happened due to close contact, lack of hand hygiene and physical distancing and no use of face mask. Having said that, WHO called for more studies to investigate such instances and assess their significance for transmission of COVID-19.
It has also called for research on the dose of virus required for transmission to occur; the settings and risk factors for super spreading events; and the extent of asymptomatic and pre-symptomatic transmission.
Agreeing with WHO’s current stand based on the information available as of now, Dr Giridhara R Babu, Professor and Head, Lifecourse Epidemiology, Indian Institute of Public Health, PHFI, Bengaluru said,
As of now the evidence suggests that if a distance is more than 1 meter then likelihood of virus spreading is less even if it’s airborne. A high propensity of virus transmission exists in a closed setting and close contact between two people where they are not using masks.
However, the scientists have claimed that the virus in the air pose risk at distances beyond 1 to 2 meter as well. This problem is especially acute in indoor or enclosed environments, particularly those that are crowded and have inadequate ventilation relative to the number of occupants and extended exposure periods. Commenting on scientists’ claim, Dr Giridhara R Babu said,
I would want to see the evidence. As of now, it’s a theoretical possibility. The real evidence suggests that in closed contacts and closed spaces like let’s say there is an AC hall where many people work. In that hall, there is one infected person and no one is wearing a mask then there is a really high risk of virus spreading within 1 meter of that person. Therefore, the propensity to spread is greater in a closed space. So it’s not just about airborne transmission but also about what kind of setting we are in.
However, Dr Harsh Mahajan, Founder Of Mahajan Imaging and Chairman of CARINGdx, believes WHO has been very cautious and careful in its guidelines for the general public and healthcare workers throughout the course of the COVID-19 pandemic. He is of the opinion that WHO should have overstated the problem and said,
Even now it (WHO) has come up with a guarded statement about the airborne transmission of this highly contagious disease. It may have been better in such circumstances for WHO and other authorities to err on the side of overstating the dangers of airborne transmission so that people end up taking more precautions and being more careful, so as to lower the chances of the rapid spread of this disease.
NDTV – Dettol Banega Swasth India campaign is an extension of the five-year-old Banega Swachh India initiative helmed by Campaign Ambassador Amitabh Bachchan. It aims to spread awareness about critical health issues facing the country. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign highlights the importance of nutrition and healthcare for women and children to prevent maternal and child mortality, fight malnutrition, stunting, wasting, anaemia and disease prevention through vaccines. Importance of programmes like Public Distribution System (PDS), Mid-day Meal Scheme, POSHAN Abhiyan and the role of Aganwadis and ASHA workers are also covered. Only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and become a Swasth or healthy India. The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene.