What after day 21 !
Today we are in the midst of the largest quarantine in the history of mankind !
A 21 day total lockdown on the entire country of 1.3 billion imposed by the Indian Government in an attempt to save the people from the Covid 19 pandemic which has unleashed a spate of disease and death all across the world. It's a bold and praise worthy decision to save the precious lives of our country men.
The novel corona virus originated from China sometime in December 2019 and since then spread like a wildfire to all the distant parts of the world by infected individuals travelling, carrying the virus with them and unknowingly transmitting it to other healthy individuals.
What we know as of today is that the virus causes a flu like illness - starting with fever, headache, sore throat (dry cough), runny nose and with some gastrointestinal symptoms like diarrhea. In most cases about 95% the disease is limited to these minor symptoms and the individual recovers. But in the elderly, previously compromised (lung diseases) and even in a small percentage of otherwise healthy individuals the disease progresses to a pneumonia sort of lung disease and may lead to respiratory distress requiring ICU care and sadly even death. The virus has a high transmissiblity and that is the reason why it has spread so rapidly across the world and has acquired pandemic proportions. The rapidity with which it threatens to infect large number of people has put the health infrastructure of most countries under a very real threat of getting overwhelmed.
With the most prevalent mode of transmission being droplet or fomite transmission from infected individuals only total quarantine of infected individuals would be the most effective methods of reducing further infections. But the fact that the virus is so 'new', has a upto 14 day incubation period and has 'so common' symptoms it actually prevents the infected individuals from being readily detected. Then, since it is not possible to identify all the infected at any given time the most effective way would be to socially distance EACH and every person -- not just the infected but also the hereto uninfected individuals - for long enough (maybe 24 days)- so that the chain of transmission is broken. Again not possible !
So How do we achieve the next best scenario - keeping in mind that the virus may also get transmitted by surface contaminated by fomites of infected individuals. The 21 day lockdown is a brave attempt to socially distance everybody for a period where most infected individuals would run their cycles of infected / disease period - get identified so that it would be possible to isolate the pockets of infection -- for further isolation and treatment. The social distancing ensures that the remaining people would be effectively saved from the infection.
So as the term goes we would be able to flatten the curve of rising infections.
Even if we don't consider the economic fall out of the lock down for now (- given the fact that disruption of all services in our country would have a huge economic fallout especially when a large chunk of our population is self-employed or salaried in the informal sector or are migrant workers) there is one thing we need to consider and that is -- 95% of the infections are likely to be mild and hence may not require actual medical help, may avoid detection yet the infection may pass to hereto healthy family members many of whom will be in stage to transmit the virus when the lock down is lifted at the end of the 21 days.
This transmission at the end of the 21 day lock-down can lead to sudden rise in cases about 2-3 weeks from the date of the lifting of restrictions !
So what does this mean. How long should the restrictions be ? As minimum or certain level of interaction is inevitable even to maintain basic survival needs there would always be a reasonable chance of infection outlasting even longer(than 21 days) lock-downs. Plus there would always be a possibility of again importing the virus till cases remain around the world. Thus, the only lasting solution for this type of viral infections is host immunity. Host immunity can be achieved only after the host (individual) has recovered from the infection or if the host has been vaccinated for a vaccine for the virus. The virus is a new one and does not have a vaccine- vaccine development and availability for general masses may take time (months maybe years ).
So what options do we have.
Let us assume that a effective vaccine is at least 2 years distant and so we need to devise a 2 year strategy - with the goals of keeping our health infrastructure from saturating so that we can give the best available help to all the ones who require it. In other words we have to keep the infected cases from peaking not just for the next one month but the next 2 years (may be more ). Since no economy today can sustain a lock down for 2 years we have look at methods beyond that too.
This study by the John Hopkins Institute - outlines the probable peaks of infection cases for the later part of the year once the lock-down like ours are lifted -India-prediction-John Hopkins(1).pdf via
These two graphs show the possible pattern of infections assuming high, medium or low infectivity (depending on prevailing conditions )of the virus post the 21 day lockdown !!
Have a look at the time line on the x-axis.
A salient point is listed in the conclusion of the study that prolonged lock-downs seriously affect the individual health (physical and mental) and resilience the people to fight the infection and such hardships in future ( point 3)
So the lock-downs have to be optimized for individual societies taking into account not just their health characters, the age distributions but also the economic resilience of the general population.
In this fight the favorable aspects for us are that a) about 95% of the infected recover without any residual deficiency b) This percentage is even higher for younger individuals (almost 99% for under 40 yrs of age ) c) ours is a young (youngest) population d) recovered cases stop shedding/transmitting the virus e) our weather is hot and humid - the virus transmission rates are likely to drop with higher temperatures.
What is our current learning experience of the lock-downs?
Lock-downs have certainly been able to break or at least dramatically slow down transmission rates.
From a purely cost- effect ratio perspective - with the current number of infected in our country (at around 850+ out of a total of 1.35 billion) we can safely assume that the vastness and magnitude of the lock down is way too heavy on the cost side ( and hence also very effective in its objective of flattening the curve ). It is this cost excess that makes prolonged lock-downs unsustainable .
We also know that the lock-down and the social media have considerably raised the awareness levels of all our countrymen towards the corona virus infection, its symptoms and the ways to prevent its spread . That's certainly can be used as an advantage now.
As we now know that the Corona virus has an incubation period of 2-14 days and a disease period of 10-12 days , just 21 days would not be enough to localize on every infected case - because the symptoms would be mild in the majority, and more so many of the family members ( who would be likely infected by then) would also be in a position to transmit the virus once the restrictions are lifted.
So can we increase the duration of the lock-down ?
Wuhan was on lockdown two times for seven weeks (49 days) each and UK has most recently announced a 6 month lock-down . But can our complete nation sustain a longer lock down ?
This one study by the London Business School -(LINK http://lbs_surico_covid19_final.pdf.pdf )beautifully demonstrates the advantages and disadvantages of the two policies - states can follow to counter the corona virus threat -
1. CONTAINMENT
2. SUPPRESSION
Ideally if we could isolate all infected individuals we could ensure that the virus dies out and that would be the best solution but that is now not possible !
If we cannot ensure that the virus dies out completely then we have to ensure that all of us develop IMMUNITY to it either by recovering from the infection or by vaccination .
For a huge population like ours these graphs would be much more prolonged and the peaks much higher and steeper . As our health infrastructure is less robust the likely causalities would be much higher, even though the containing interventions do make a significant impact they may not be enough to make a significant difference by themselves.
While Containment refers to a more localised case to case (and contacts) strategy of identification and isolation, Suppression is the generalised social distancing that is achieved by lock downs
Suppression delays the spread of infection much more effectively but once the lock down is lifted very soon the pre-lock down scenario is reached threatening similar spread of infection. In effect all the benefits of the lock-down may very soon be lost but the cost incurred is irreversible. So, if it was a short term target maybe lock downs were the best alternative -- till the vaccine would be available, affordable for all. But we all know that the vaccine is some time away.
Containment, by itself even though runs the risk of going of out control overwhelming our health infrastructure but containment is likely to have less economic implications in the long term as we are at least moving towards a stage where we can finally open up and function fully and reclaim our normal status !!
So how about a Combination of Suppression and Containment !!
We are currently following the Suppression strategy and our rate of new cases by latest reports has fallen down by 60% . Our Health Infrastructure is not yet burdened . Weather is turning favorable (more hot and humid).
So how long do we wait before we switch from lock down to containment strategy - for a limited period - where we aggressively continue to observe all the precautions required at personal levels to prevent the spread of the virus. But we allow limited public transport- allow individual shops.
We allow people to return to their work.
But we continue to maintain a total ban on all forms of public gathering (schools, religious, social or otherwise). I suppose the best parameters to decide this would be 'new patients requiring specialized (ICU) care' and the 'new cases detected' . If both the figures show a considerable decline that might be a opportune time to make the switch.
During all this time we concentrate on ramping up our health infrastructure and keep an eye on the hospitalizations ( just 'infections' may not be a parameter concentrating upon, though its more alarming and hyped by media). As soon as the dedicated Covid-19 health infra reaches a critical level (say around 40% occupancy n rising - I hope it never does ) we AGAIN lock-down for 21 days (or even a longer periods - we'll soon have more data to decide better). This is what would be 'rolling suppression' or 'staggered suppression' or alternate suppression - containment . We could also have 'territory specific suppression' surrounded by area of containment (umbra-penumbra). These modifications would somewhat mitigate the financial setback of the lock-downs which may prove hugely beneficial in the long term, without reducing the health benefits of lock-downs.
By this strategy not only would every one be more prepared for the lock downs, everyone would also be more serious and committed towards it . This way not only our economy would have more breathing time it would be also able to sustain the 'Suppression' strategy for a longer period .It would also give us more time to ramp up our health infrastructure.
What would be the best strategy perhaps only time will tell, but as of now what we know is that we need to be prepared for the long haul (much more than 21 days ) so its better we prepare for it !!
---Saurabh Agrawal
with valuable inputs from Rahul Joshi
A 21 day total lockdown on the entire country of 1.3 billion imposed by the Indian Government in an attempt to save the people from the Covid 19 pandemic which has unleashed a spate of disease and death all across the world. It's a bold and praise worthy decision to save the precious lives of our country men.
The novel corona virus originated from China sometime in December 2019 and since then spread like a wildfire to all the distant parts of the world by infected individuals travelling, carrying the virus with them and unknowingly transmitting it to other healthy individuals.
What we know as of today is that the virus causes a flu like illness - starting with fever, headache, sore throat (dry cough), runny nose and with some gastrointestinal symptoms like diarrhea. In most cases about 95% the disease is limited to these minor symptoms and the individual recovers. But in the elderly, previously compromised (lung diseases) and even in a small percentage of otherwise healthy individuals the disease progresses to a pneumonia sort of lung disease and may lead to respiratory distress requiring ICU care and sadly even death. The virus has a high transmissiblity and that is the reason why it has spread so rapidly across the world and has acquired pandemic proportions. The rapidity with which it threatens to infect large number of people has put the health infrastructure of most countries under a very real threat of getting overwhelmed.
With the most prevalent mode of transmission being droplet or fomite transmission from infected individuals only total quarantine of infected individuals would be the most effective methods of reducing further infections. But the fact that the virus is so 'new', has a upto 14 day incubation period and has 'so common' symptoms it actually prevents the infected individuals from being readily detected. Then, since it is not possible to identify all the infected at any given time the most effective way would be to socially distance EACH and every person -- not just the infected but also the hereto uninfected individuals - for long enough (maybe 24 days)- so that the chain of transmission is broken. Again not possible !
So How do we achieve the next best scenario - keeping in mind that the virus may also get transmitted by surface contaminated by fomites of infected individuals. The 21 day lockdown is a brave attempt to socially distance everybody for a period where most infected individuals would run their cycles of infected / disease period - get identified so that it would be possible to isolate the pockets of infection -- for further isolation and treatment. The social distancing ensures that the remaining people would be effectively saved from the infection.
So as the term goes we would be able to flatten the curve of rising infections.
Even if we don't consider the economic fall out of the lock down for now (- given the fact that disruption of all services in our country would have a huge economic fallout especially when a large chunk of our population is self-employed or salaried in the informal sector or are migrant workers) there is one thing we need to consider and that is -- 95% of the infections are likely to be mild and hence may not require actual medical help, may avoid detection yet the infection may pass to hereto healthy family members many of whom will be in stage to transmit the virus when the lock down is lifted at the end of the 21 days.
This transmission at the end of the 21 day lock-down can lead to sudden rise in cases about 2-3 weeks from the date of the lifting of restrictions !
So what does this mean. How long should the restrictions be ? As minimum or certain level of interaction is inevitable even to maintain basic survival needs there would always be a reasonable chance of infection outlasting even longer(than 21 days) lock-downs. Plus there would always be a possibility of again importing the virus till cases remain around the world. Thus, the only lasting solution for this type of viral infections is host immunity. Host immunity can be achieved only after the host (individual) has recovered from the infection or if the host has been vaccinated for a vaccine for the virus. The virus is a new one and does not have a vaccine- vaccine development and availability for general masses may take time (months maybe years ).
So what options do we have.
Let us assume that a effective vaccine is at least 2 years distant and so we need to devise a 2 year strategy - with the goals of keeping our health infrastructure from saturating so that we can give the best available help to all the ones who require it. In other words we have to keep the infected cases from peaking not just for the next one month but the next 2 years (may be more ). Since no economy today can sustain a lock down for 2 years we have look at methods beyond that too.
This study by the John Hopkins Institute - outlines the probable peaks of infection cases for the later part of the year once the lock-down like ours are lifted -India-prediction-John Hopkins(1).pdf via
Have a look at the time line on the x-axis.
A salient point is listed in the conclusion of the study that prolonged lock-downs seriously affect the individual health (physical and mental) and resilience the people to fight the infection and such hardships in future ( point 3)
So the lock-downs have to be optimized for individual societies taking into account not just their health characters, the age distributions but also the economic resilience of the general population.
In this fight the favorable aspects for us are that a) about 95% of the infected recover without any residual deficiency b) This percentage is even higher for younger individuals (almost 99% for under 40 yrs of age ) c) ours is a young (youngest) population d) recovered cases stop shedding/transmitting the virus e) our weather is hot and humid - the virus transmission rates are likely to drop with higher temperatures.
What is our current learning experience of the lock-downs?
Lock-downs have certainly been able to break or at least dramatically slow down transmission rates.
From a purely cost- effect ratio perspective - with the current number of infected in our country (at around 850+ out of a total of 1.35 billion) we can safely assume that the vastness and magnitude of the lock down is way too heavy on the cost side ( and hence also very effective in its objective of flattening the curve ). It is this cost excess that makes prolonged lock-downs unsustainable .
We also know that the lock-down and the social media have considerably raised the awareness levels of all our countrymen towards the corona virus infection, its symptoms and the ways to prevent its spread . That's certainly can be used as an advantage now.
As we now know that the Corona virus has an incubation period of 2-14 days and a disease period of 10-12 days , just 21 days would not be enough to localize on every infected case - because the symptoms would be mild in the majority, and more so many of the family members ( who would be likely infected by then) would also be in a position to transmit the virus once the restrictions are lifted.
So can we increase the duration of the lock-down ?
Wuhan was on lockdown two times for seven weeks (49 days) each and UK has most recently announced a 6 month lock-down . But can our complete nation sustain a longer lock down ?
This one study by the London Business School -(LINK http://lbs_surico_covid19_final.pdf.pdf )beautifully demonstrates the advantages and disadvantages of the two policies - states can follow to counter the corona virus threat -
1. CONTAINMENT
2. SUPPRESSION
If we cannot ensure that the virus dies out completely then we have to ensure that all of us develop IMMUNITY to it either by recovering from the infection or by vaccination .
For a huge population like ours these graphs would be much more prolonged and the peaks much higher and steeper . As our health infrastructure is less robust the likely causalities would be much higher, even though the containing interventions do make a significant impact they may not be enough to make a significant difference by themselves.
While Containment refers to a more localised case to case (and contacts) strategy of identification and isolation, Suppression is the generalised social distancing that is achieved by lock downs
Suppression delays the spread of infection much more effectively but once the lock down is lifted very soon the pre-lock down scenario is reached threatening similar spread of infection. In effect all the benefits of the lock-down may very soon be lost but the cost incurred is irreversible. So, if it was a short term target maybe lock downs were the best alternative -- till the vaccine would be available, affordable for all. But we all know that the vaccine is some time away.
Containment, by itself even though runs the risk of going of out control overwhelming our health infrastructure but containment is likely to have less economic implications in the long term as we are at least moving towards a stage where we can finally open up and function fully and reclaim our normal status !!
So how about a Combination of Suppression and Containment !!
We are currently following the Suppression strategy and our rate of new cases by latest reports has fallen down by 60% . Our Health Infrastructure is not yet burdened . Weather is turning favorable (more hot and humid).
So how long do we wait before we switch from lock down to containment strategy - for a limited period - where we aggressively continue to observe all the precautions required at personal levels to prevent the spread of the virus. But we allow limited public transport- allow individual shops.
We allow people to return to their work.
But we continue to maintain a total ban on all forms of public gathering (schools, religious, social or otherwise). I suppose the best parameters to decide this would be 'new patients requiring specialized (ICU) care' and the 'new cases detected' . If both the figures show a considerable decline that might be a opportune time to make the switch.
During all this time we concentrate on ramping up our health infrastructure and keep an eye on the hospitalizations ( just 'infections' may not be a parameter concentrating upon, though its more alarming and hyped by media). As soon as the dedicated Covid-19 health infra reaches a critical level (say around 40% occupancy n rising - I hope it never does ) we AGAIN lock-down for 21 days (or even a longer periods - we'll soon have more data to decide better). This is what would be 'rolling suppression' or 'staggered suppression' or alternate suppression - containment . We could also have 'territory specific suppression' surrounded by area of containment (umbra-penumbra). These modifications would somewhat mitigate the financial setback of the lock-downs which may prove hugely beneficial in the long term, without reducing the health benefits of lock-downs.
By this strategy not only would every one be more prepared for the lock downs, everyone would also be more serious and committed towards it . This way not only our economy would have more breathing time it would be also able to sustain the 'Suppression' strategy for a longer period .It would also give us more time to ramp up our health infrastructure.
What would be the best strategy perhaps only time will tell, but as of now what we know is that we need to be prepared for the long haul (much more than 21 days ) so its better we prepare for it !!
---Saurabh Agrawal
with valuable inputs from Rahul Joshi
Informative
ReplyDeleteReally nice write up!
ReplyDeleteExcellent write up and very informative..
ReplyDeleteVery informative and helpful. Thanks Saurabh. Humanity first
ReplyDeleteVery well analysed
ReplyDelete