Precautions To Take Till Airborne Transmission Of COVID-19 Is Further Researched And WHO Assesses The ‘Emerging Evidence’

New Delhi: On Monday (July 6), Oxford University Press for the Infectious Diseases Society of America published an open access article titled ‘It is time to address airborne transmission of COVID-19’. Along with the authors, 239 scientists from 32 countries have supported the argument that there is a potential for airborne spread of COVID-19. The claim essentially means that the virus can travel in the air so even if one doesn’t come in direct contact with a COVID-19 infected person, he/she can catch the virus. This also means that an individual might not be safe in his/her house.

Studies by the signatories and other scientists have demonstrated beyond any reasonable doubt that viruses are released during exhalation, talking, and coughing in microdroplets small enough to remain aloft in air and pose a risk of exposure at distances beyond 1 to 2 m from an infected individual, states the article.

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However, the World Health Organsiation (WHO) has always said that the COVID-19 disease spreads primarily from person to person through small droplets from the nose or mouth, which are expelled when a person with COVID-19 coughs, sneezes, or speaks. These droplets are relatively heavy, do not travel far and quickly sink to the ground. People can catch COVID-19 if they breathe in these droplets from a person infected with the virus. This is why it is important to stay at least 1 meter) away from others.

These droplets can land on objects and surfaces around the person such as tables, doorknobs and handrails. People can become infected by touching these objects or surfaces, then touching their eyes, nose or mouth. This is why it is important to wash your hands regularly with soap and water or clean with alcohol-based hand rub, WHO had said explaining how COVID-19 spread.

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239 scientists believe that handwashing and social distancing are appropriate for droplet precautions but insufficient to provide protection from virus-carrying respiratory micro-droplets released into the air by infected people. The scientists have written an open letter to WHO and are advocating for the use of preventive measures to mitigate this route of airborne transmission. The team has even suggested three vital measures:

1. Provide sufficient and effective ventilation (supply clean outdoor air, minimise recirculating air) particularly in public buildings, workplace environments, schools, hospitals, and aged care homes

2. Supplement general ventilation with airborne infection controls such as local exhaust, high-efficiency air filtration, and germicidal ultraviolet lights

3. Avoid overcrowding, particularly in public transport and public buildings

In a virtual media briefing on July 7, WHO addressed the debate around the airborne transmission of COVID-19 and acknowledged there is ‘emerging evidence’ in this field.

We believe that we have to be open to this evidence and understand its implications regarding the modes of transmission and also regarding the precautions that need to be taken, said Professor Benedetta Allegranzi, WHO’s technical lead.

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Dr Maria Van Kerkhove, Technical Lead COVID-19, WHO Health Emergencies Programme informed that the organisation has been in touch with the scientists since April and is producing a scientific brief consolidating growing knowledge around transmission.

We are also looking at the possible role of airborne transmission in other setting where you have poor ventilation. We will share our brief in the coming days, said Dr Maria Van Kerkhove.

What Is Airborne Transmission?

Airborne transmission simply means a virus can be carried through the air and possibly infect people breathing contaminated air. There are some viruses which do travel in air like measles. In the case of coronavirus, the debate is still on as there is no clarity on how far the virus can travel in the air, and for how long it remains active.

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A virus can be airborne in three ways – through aerosols, smaller droplets and when the virus is light enough to travel in the air. Explaining what are aerosols, Dr Rajesh Parikh, Director, Medical Research at Jaslok Hospital, said,

When you spray deodorant or perfume and fine particles come out, that’s an aerosol. It can come out in different circumstances like in hospitals, when we put a tube inside a patient’s mouth to help in breathing. Aerosols are airborne but not everything that is borne by air is aerosol.

According to scientists, the current guidance from numerous international and national bodies focuses on handwashing, maintaining social distancing, and droplet precautions and do not recognise airborne transmission except for aerosol-generating procedures performed in healthcare settings.

Is Novel Coronavirus Airborne? Experts Answer

To understand scientists’ claims and what this is going to mean for the global battle against the Coronavirus pandemic, NDTV spoke to medical experts.

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Explaining different kinds of aerosols and how they can infect others, Dr Shekhar C Mande, Director General of Central Science Industrial Research said,

All of us agree that the principal route of infection is through respiration – when we breathe in air and breathe out. When an infected person coughs, he emits aerosols and those aerosols are typically big in size something like 10 microns or larger. However, there is increasing evidence that is being presented that aerosols are also generated while normal speaking and are smaller in size, less than 5 microns. The Stokes’ law suggests that larger aerosols will settle down on surfaces quickly while smaller will remain suspended in the air for a longer time. Both the larger and smaller aerosols can have virus particles in them and therefore can infect.

Dr Shekhar C Mande believes that the world is still learning about the virus and the current understanding is tilting towards that the SARS-Cov-2 also spreads through smaller aerosols.

Dr M. Vali, Senior Physician at Ganga Ram Hospital noted that the Coronavirus situation is getting serious day by day. The number of Coronavirus cases in India is on the rise and the country is now the third worst-hit nation by COVID-19 after US and Brazil. He said,

These are all indications that coronavirus can be infecting more people through an unknown route. Open transmission by air and the presence of coronavirus in the air which the scientists have claimed to be will be more disastrous.

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What’s interesting is, in March, a book titled ‘The Coronavirus – What You Need To Know About The Global Pandemic’ talked about the airborne transmission of coronavirus. In the book, while explaining the difference droplet transmission and airborne infections, writers had stated,

Some nuance can be lost in the oversimplified false dichotomy of airborne versus droplet transmission; they are not mutually exclusive.

Dr Rajesh Parikh, Director, Medical Research at Jaslok Hospital and author of the said book clearly stated that the distinction between droplet borne and airborne is very hazy and ambiguous and added,

In our book, we have quoted somewhat complex equation called the Wells evaporation curve. In a nutshell, it says, as the droplet containing the virus falls to the ground, depending on the humidity, ambient temperature and the wind velocity it evaporates; becomes lighter even before it hits the ground, when it’s light enough, it can be airborne. I think it’s about time WHO comes to terms with it and accept it because otherwise, it lulls people into a false sense of security which is always dangerous.

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Dr Harsh Mahajan, Founder Of Mahajan Imaging and Chairman of CARINGdx agreed with Dr Rajesh Parikh and said what scientists have been claiming is not new. Giving an example of the same, he said,

Definitely the virus is airborne and we have known this for a long time. Let’s say in a restaurant, there are two people A and B. A has COVID-19 and is sitting closer to AC or fan and B is sitting next to A which means air from AC or fan will first hit A and then reach to B. In this case, virus particles can be carried in the air of fan and reach B. I know at least one such case, it was reported somewhere in the west.

Dr S. Venkataraman, Senior consultant, MGM Healthcare shared that they have had patients who walk in and say, ‘I was by and large inside the house and how did I pick it up and how are my parents who have never stepped out of the house becoming positive?’

Virus being airborne plays a crucial role in closed spaces and areas that lack ventilation like offices because aerosols remain suspended in the air for a few hours. Hence, Dr Harsh Mahajan suggests finding answers to three questions – whether virus suspended in the air is in infectious form; how long it remains suspended in the air; how far it travels while still remaining infectious.

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Dr Giridhara R Babu, Professor and Head, Lifecourse Epidemiology, Indian Institute of Public Health, PHFI, Bengaluru also called for evidence on transmission in terms of distance. He said, if it were to be completely airborne, by now most people would have got infected in India because the transport like bus has opened up. Therefore, he suggested research on how far the virus can travel and the size of the particulate matter.

We have always known about virus being airborne. It’s being transmitted through air conditioning trunk. This is why people are being kept in isolation with no air conditioning. It’s just WHO has not come out with those recommendations but we have always known them and following them, said Dr Vivek Nangia, Principal Director and Head of Department for Institute of Respiratory and Critical Care Medicine at Max Hospital in Saket.

How To Protect Oneself From COVID-19 If Its Airborne?

Dr Shekhar C Mande says that aerosol form is when minute respiratory droplets can float in the air for a while but this does not travel with the wind and quickly settles. Therefore, he recommends wearing masks, an effective way of protecting oneself from contracting the virus.

If an infected person wears a mask then the probability of transmitting the virus gets low. Similarly, if a non-infected person wears a mask, the probability of catching coronavirus reduces. People don’t need to be scared, said Dr Shekhar C Mande.

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Dr M. Vali also emphasised on the regular use of mask and he even suggested using a face cover while indoors. He said,

If the claim is true, it means people should not come out and they should wear the mask very strictly. I’m wearing at home and instructing the same to my children.

Further talking about what could be the revised guidelines, as asked by the scientists, Dr Rajesh Parikh said,

Do not ease out on your safety measures particularly when you are in closed spaces such as elevators. Two months ago, when everyone was talking about the infections in Dharavi in Mumbai and how bad the situation was, I remarked that those of us who live in high rises shouldn’t feel so smug because, at the end of the day, high rises are like vertical Dharavis when it comes to the number of people using a common space. One should not especially feel safer because apartments are large and we have more space around us or we live in affluent neighbourhoods. We have to be careful because if it’s airborne as it seems to be then one could contract the virus within the house so generally, one should wear a mask, as often as possible. And maintain a social distance of course.

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Dr Giridhara R Babu clarified that no special and additional guidelines will be required. Instead, the existing guidelines especially to contain the transmission in indoor spaces will have to be updated rather than outdoor guidelines. He said,

Areas, where enforcement is required, might expand. Mask will definitely be made mandatory even within the houses. People who are using equipment in dental practices where it can spread through the airborne route will have to be changed.

Commenting on the new data and studies being put out in the area of transmission and how WHO takes it, in a virtual media briefing, Dr Soumya Swaminathan, WHO Chief Scientist informed that the science is constantly changing and the team reviews about 500 new publications a day. She added,

We do what’s called a living systematic review. We are of course focused on public health guidance and so any guidance that we put out has implications of course for billions of people around the world, so it has to be carefully considered.

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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.