Herd needs masks more than unnecessary medical research
We do not even know the infective dose of Covid19, yet research community is making assessment about efficacy of various interventions. I think sometimes plain logic serves us better than the boxed approach of science!
We needed a bullet proof jacket for a war. Fifty one manufacturers supplied samples that were tested in our lab. We diligently test them all and declared one of them as the worthy jacket. Praises were showered and the lab was honoured.
Everything worked well for everyone but for a small problem. We did not know the kind of bullets our enemy would be using. We were happy nevertheless. The lab research paper got published. Got peer reviewed by lot of our friends, who had taken our help in getting their papers reviewed. Everyone was happy that we were ready for the war.
Our soldiers were damn scared!
This story aptly summarises the Covid19 medical research scenario. There are numerous studies published in well-known medical journals saying nothing at all. Published just for the heck of it, they come across as cases of misplaced priorities or opportunistic publications during epidemic. The misleading headlines are then picked up by the journalists and broadcast as the ultimate truth.
I do not want to quote any specific study. Those interested can scan reputed online medical journals to experience the discrepancy themselves; especially the gap between the title and conclusion /discussion.
Sadly, the problem does not end there. Many of the ‘headlines’, based on these ‘researches’, may lead to awkward administrative decisions and actions. Too much dependence on research papers rather than logic and systems thinking based approach is perhaps making us overlook the obvious.
The biggest piece of the puzzle is missing
Anyone who knows anything about science knows that every experiment is conducted on the basis of certain assumptions. These assumptions are the box within which the experiments, when conducted, will throw consistency of results. Getting the assumptions correct is perhaps as important as the experiment itself. Every scientific theory or law known to mankind, even something as basic as newton’s law of motion, ultimately rests on some set of assumptions.
So what are the assumptions on which Covid19 research rests? What makes a study proclaim that a cloth mask would work or not? Why lockdown is a must?
There are many things we ‘know’ about Covid19. Medical research community seems to agree that droplets, even from asymptomatic patients, contaminate surfaces that transmit disease. They agree to the fact that bio-aerosols play a role in transmission and that they too ultimately contaminate the surfaces they land on.
Technically, these facts are pretty obvious, expect for the role of asymptomatic patients. What we need to really know is whether there are other modes of transmission. Hopefully they do not exist.
A serious matter of concern is that we are getting overwhelmed by research papers on strange topics and senseless projections or conclusions while the biggest pieces of Covid19 transmission puzzle is missing. And no one seems to be asking about them. The key questions, answers to which will make us battle-ready, are –
- Droplets (surface contamination) or aerosols – which one of them poses greater risk?
- What is the role, in terms of percentage, played by each of these modes in disease transmission?
- What is the minimum ‘infective dose’ of the SARS-CoV2? (Infective dose is that minimum exposure that would result in an infection)
Basically, we do not have the answers to these fundamental questions. And yet the medical research community seems to be making claims on efficacy of various interventions, without stating upfront that we are testing bulletproof jackets without the knowledge of the bullets that we are going to face.
Lockdown or herd immunity
There is no medicine or vaccine in sight. Meanwhile, the virus seems to have already undergone multiple mutations. As we are unaware about the key aspects of disease spread, at best we can make some logical assumptions based on available data and work towards plausible solutions.
One of the approaches being applied globally is lockdown. While it may delay the spread, its economic impact is going to be immense and will eventually hit the lower strata of the society in terms of human lives. Ironically, saving human lives is the purpose of the lockdown.
Another approach under consideration is herd immunity. There are strong divergent views about it applicability due to its negative outcome possibilities in terms of human lives. Some say, it is almost like accepting fate and letting many die.
But we have a war to win. If the virus is here to stay, then we have no other option but to develop herd immunity because we cannot be in a permanent state of lockdown. The human price of lockdown may be much higher than that of a herd immunity drive. Untangling this mess and finding a middle path seems to be the most logical idea.
The keys to untangle the mess
If there are no specific researches available for SARS-CoV2 on specific matters then what is the harm in taking a heuristic approach by assuming that the behaviour of SARS-CoV2 is consistent with other similar viruses (similarity of family, mode of transmission, physical properties, etc.). We also need to give desired weightage to the opinions of people with experience. Based on these, we can visualise the larger landscape that gives us a fuller and better view of the current state of affairs and find solutions.
Here are certain facts that we need to consider for creating that larger picture
- Transmission potential of asymptomatic patient is similar to that of symptomatic patients.
(Source – The New England Journal of Medicine )
- Social distancing as public health response is important.
(Source – Centre for Disease Control and Prevention)
- Higher amount of exposure to virus during infection may lead to worse symptoms.
(Source – New Scientist)
- “On the basis of previous work on SARS and MERS coronaviruses, we know that exposures to higher doses are associated with a worse outcome and this may be likely in the case of Covid-19 as well.” – Professor Willem van Schaik, Professor in Microbiology and Infection, University of Birmingham
(Source – Science Media Centre )
- “Likelihood of virus transmission increases with duration and frequency of exposure of an uninfected individual with someone infected with the virus.” – Prof Jonathan Ball, Professor of Molecular Virology, University of Nottingham
(Source – Science Media Centre)
- Aerosol Filtration Efficiency of respiratory cloth masks improved with multiple layers. Filtration efficiencies of the hybrid combinations like cotton & silk, cotton & chiffon, etc., was as high as 80% for aerosols and over 90% for droplets.
(Source – American Chemical Society)
- Gaps due to an improper fit of the mask can result in over a 60% decrease in the filtration efficiency
(Source – American Chemical Society)
- “When one deals with infectivity rather than detectability, extinguishing infectivity is far quicker.” From Prof Richard Tedder, Visiting Professor in Medical Virology, Imperial College London
(Source – Science Media Centre)
Untangling the mess
Within available means and technology, it is impossible to test a large cross section of society as a pre-emptive measure. As the asymptomatic patients seem to have similar transmission potential as a symptomatic patient, a silent and steady spread of the disease is highly likely. Many asymptomatic patients may recover with minimal symptoms, acting as carriers without knowing that they are one.
When researchers deal with masks, their focus seems to be 100% efficiencies. Such efficiencies are needed in hospital environments and not otherwise. Even if the study of American Chemical Society quoted above is partially true, the two layered cloth mask will significantly reduce the spread of virus in the environment. When both the infected and the uninfected person are wearing two layered cloth mask, then we are effectively talking about four layered cloth mask between those two people. Even if the efficiency of cloth mask is 30%, the combined efficiency would almost double.
The masks will reduce overall volume as well as concentration of droplets and aerosols in the environment. Reduced concentration should, logically, reduce the chances of transmission as it would impact the duration and frequency of exposure thereby impacting the availability of infective dose. Ideally, the reduced exposure should not only reduce the chances of infection but also help develop immunity as the body may get exposed to a harmless dose. This appears to be a good better mode of gaining herd immunity. Strict and efficient implementation could yield good results in a shorter timeframe.
Well-fitting cloth masks will perform far better than ill-fitting surgical masks. All of us have seen pictures of volunteers and cops roaming around with surgical masks, with their noses exposed. That is equivalent to not wearing a mask. This fact also suggests that people need better fitting masks that does not hinder their work. Cloth masks can easily address this problem. Another benefit of cloth masks is its decentralised production for meeting the widespread requirement.
The combination of cloth masks with basic social distancing measures and hand washing could yield good results. Caution with regards to vulnerable sections of society and a rapid testing based response to spikes can possibly help us deal with Covid19 as if it was ordinary flu. Thinking further on these lines can help us find more effective solutions. The administrative machinery needs to think and be convinced about a solution. Only then it will be able to effectively relay the message so that people understand the logic and follow the protocol.
Medical research papers can be good reference material but not solutions as they are tend to look at things through a single lens. Plus many of them are written with the sole intention of having written and published them. Solutions lie in logical and holistic interpretations of relevant research with respect to current state of knowledge and local ground realities.
Sometimes plain logic is better than the boxed approach of science that can see the data but is pretty blind to reason!
The various aspects of a well-fitting and efficient mask, based on the current understanding of the problem, are discussed in the article – Anatomy of an efficient face mask.