That you get Covid-19 not only from people coughing, sneezing or just breathing close to you, but from breathing their exhaled breath at a distance has now been accepted by the World Health Organisation (WHO).
We need to understand what this means for controlling the rapidly evolving third (or fourth) wave of the pandemic in SA and what it says about how we find and use scientific "truth" to make policy.
Last week, there was a new development.
WHO declared that Covid-19 is spread not only by larger droplets containing the coronavirus, but by tiny particles (aerosols) that can drift a considerable distance through the air. Scientists who study these phenomena have been saying all along that spread of virus-bearing aerosols, in indoor spaces, at short (1.5-2m) and long distances, rather than contact or droplets (from coughing or sneezing) is probably the main mode of transmission.
Accepting this idea when aerosol scientists were shouting it out with evidence, more than a year ago, could have allowed us to stop much of the "hygiene theatre" and to focus on the things that truly make a difference in suppression of this disease - wearing high quality masks to prevent breathing out and breathing in of coronavirus, simple and sensible hand hygiene practices, and most importantly, reducing the concentration of re-breathed air around us that can carry the coronavirus into our lungs.
What are the implications for South Africa? "Zero Covid", or at least low levels of Covid, may still be possible as we face down the third wave of Covid-19 while we try to get vaccinated, without shutting down the economy ("lockdown").
Here is how it might be accomplished:
- Breathe fresh air - by reducing the number of people crowded together in indoor spaces where Covid is spread, improving the ventilation (e.g. open the windows) of those spaces, and, if those interventions are not possible, using mechanical systems to improve air quality;
- Wear the best mask possible in occupied, indoor spaces. A properly fitted N95 or equivalent mask is best, if available; a close-fitting, triple-layer cloth mask, or doubling up your mask are alternatives;
- Comply with, but do not rely solely on social distancing (the 1.5m rule);
- Reduce "hygiene theatre" (the squirt of sanitiser on the hand, fogging, disinfecting tunnels, obsessive hourly surface cleaning, inaccurate temperature scanning, symptom checking that is a "tick-box" exercise). These are costly, essentially useless efforts that create a completely false sense of confidence;
- Clean your hands properly after contact with possibly contaminated surfaces and before touching your face, another person, or your food;
- Enable people who get sick to safely isolate themselves without economic hardship or penalty (paid sick leave); and
- Encourage everyone to go outdoors, or semi-outdoors, for all communal human activity - dining, working, playing - while we are in this pandemic. It is harmless to keep face coverings on in outdoor spaces - as a social signal that one cares.
How crowded is crowded? How do you clean the air? Guidelines based on occupancy, activity, size of the space, and rates of Covid-19 in the community, are helpful and readily available.
Measurements of the carbon dioxide (CO2) concentration in indoor spaces with a handheld meter gives a quantitative estimate of air quality and safety. When (or before) CO2 concentration reaches over 800 parts per million, do something - open the windows ("ventilation"), remove the virus from air circulating through the HVAC (Heating Ventilation Air Conditioning) system (HEPA- or MERV- or ISO-rated filters), or kill the virus using ceiling mounted UV light installations.
The bigger question is how we learn from and react to this pandemic - and prepare for the next one. Science progresses through new views and ideas, subject to rational debate and experimentation, in the full light of day.
The uncertainty that may be created as part of this process is not always helpful for public health messaging. Worse than this uncertainty, however, is failing to acknowledge it. When evidence changes, scientific "truth" changes, and decisions should follow.
Public health messaging
Public health messaging needs an upgrade. People should be treated like adults capable of understanding the rationale for (and science behind) public health decisions.
They should be encouraged to accept that the authorities aren't always, cannot always, be right, but that they can and will make course corrections based on publicly shared best evidence, obtained from experts. For policy-making, economic trade-offs may be necessary.
Our actuaries, statisticians and epidemiologists have been predicting and are now watching the third wave of Covid-19 in SA. We aren't putting enough effort into developing and sharing the actions that might prevent it in the face of new knowledge.
We can predict a third wave and now understand how Covid is spread - and not spread. We can do a better job of preventing a devastating third wave of Covid-19 massive lockdowns that would further damage our economy. Sensible, practical measures are available. We should implement them. Our lives and our livelihoods depend on it.
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