• Dr, Vijayshree Patil

Understanding Covid-19 : Part 2



In the previous post, we spoke about how we can stop the dreaded coronavirus from spreading and repeatedly spoke about the need to stay home. Today, let’s talk about how that works in what the experts refer to, as ‘Flattening the Curve’.

Let us look at this picture that is being circulated widely on social media.



The first person in red, represents what we call the Index Case or Patient 0 or in simpler terms, where it all started. So now this patient has two alternatives, either they stay home and quarantine themselves, or they can intermingle freely in society. If they choose to socialise, they are likely to infect others. Now that’s a no brainer, right?!


The question is, how many people can they infect?


This brings us to another important epidemiological term, ‘R0’ meaning R nought. So higher the R0, higher is the infectivity. The R0 for Covid-19 is estimated to be around 2.5-3.0, which means that a patient



with Covid is likely to infect 3 other patients, who will infect 3 more each (10 people infected now) and then 3 more each (28 patients now, including the index case!) and so on. This is where Covid differs from swine flu, its more deadly cousin. Swine flu has an R0 of around 1.5. The diagram given above shows you the relative contagiousness of common infections.


That brings us to the next question, how do we stop the spread?


Since we know that Covid is a relatively large virus that is only transmitted by aerosolization or droplet transmission, all you have to do, is stay away from the droplets. And how do you do that? You stay at home of course! Particularly if you have symptoms, so your infected droplets stay far away from everyone else. Look at the diagram below. This is one of the easiest ways to look at how effectively we could break the chain of transmission, if the infected stayed home.


So why should you stay home even if you are not infected?


Because Covid is quite the sneaky little devil! It has a long incubation period of 14 days and around 80% of the infected will not show any symptoms at any point of time. This means that your friendly neighbour, the cabbie taking you to work, the milkman, your colleague, all of whom seem absolutely hale and hearty, could be carrying the infection.


But what if you have to leave home to pick up groceries or vegetables or medicines? How do you stay safe?


This is where social distancing comes in. If you absolutely must leave home, you need to stay far away from everyone. How far away you ask? The recommended distance is 6 feet to prevent the virus from reaching you even with forceful aerosolization due to coughing and sneezing.



Now while not all of us can manage to be dressed like the gentleman below to enforce social distancing, we can mentally chalk out 6 feet and try to maintain that. 6 feet is usually how long a mattress or a dining table or two shopping carts end to end are.




If you, as an individual, maintain social distancing, will that even have an impact the global picture?


There is an excellent chance that it might. All it takes, is one person stopping the spread to hundreds or even thousands of people. If you go back to the R0 diagram, you will see, that if just one of the three contacts socialized, ten cycles of transmission later, 59049 could get infected (310). This is more than the population of Lonavala!!! If you look at it from a different perspective, if one infected person stayed home, Lonavala does not get infected.

So, does this mean, that if everyone stays home for 14 days, Covid will disappear?


Unfortunately, it doesn’t. Let us take the state of Maharashtra as an example. On the 22nd of March, after the Janata Curfew, a curfew was announced till the 31st of March. For the sake of assumption, let us assume that all of the 11.42 crores of people stayed home. (They aren’t!! Some people who aren’t essential service providers are still flouting the rules and breaking curfew! But for our example, let us assume that everyone stayed home) up until the 22nd, when everyone was freely walking around, some asymptomatic carriers were still unaware and were spreading the disease. Hence, they and their contacts, are in various stages of the disease already. At the end of 14 days, the asymptomatic carrier, (let us call him A) can continue to be asymptomatic like in 80% of the cases, and will have possibly infected his own family members but no one else and have recovered completely, in this period. When these family members leave home, they will infect others in the population, causing a second peak.


What is the point of the lockdown or curfew then?


We have already established that by staying home, A is now a hero by saving the whole of Lonavala. And by having the whole state under lockdown, we have saved many more towns and even cities by this point. When A’s family members go out now, we assume that they will still continue social distancing because they know that it is not over yet. If A has 10 family members, who he has infected, only 20% or 2 of them will show symptoms. They will then go to the hospital and be treated, and with them, their contacts (the other 8 people who A has infected) will get tested and isolated too. Again, the spread of the virus has hit a significant roadblock.


This is obviously a very simplified way of looking at it. It does not take into account the essential service providers who still continue to get exposed or the other asymptomatic carriers who still spread the disease and cannot be traced. It is just to give you an idea about how lockdowns work.


The purpose of the lockdown, is to delay the epidemic, reduce the number of infected and give the healthcare system some time to properly treat the infected without compromising safety and allow time for research for a cure/vaccine. There is a lovely chart to help you understand how these measures work. The brown curve represents the infected population, where the height is the number of infected and the length represents the passage of time. The difference between the free-for-all and the extensive distancing chart, is what is known as ‘flattening the curve.’




Why is it particularly important for India to flatten the curve?


If you turn on any international news channel now, you will see that most of the developed nations of the world, which spend so much more than India on healthcare, have lesser populations and better healthcare facilities, are facing what appears to be the biggest health crisis of recent times. The disease burden and measures that need to be taken to treat the disease and prevent its spread, are not working. In a country like ours, where basic health access itself is a challenge, if we do reach this phase, it would be disastrous.

Given our strained resources and large population living in overcrowded conditions, do we even stand a chance of escaping the carnage created by Covid?


The Indian administration is fully aware that their infrastructure and resources to be able to effectively deal with such widespread infection and community transmission, so they have pro-actively taken measures to try and slow the spread of the disease. India started imposing travel restrictions as early as 11th of March, with only 62 confirmed cases. Home quarantine was advised for all travellers coming from affected nations. There was flak from the WHO for the extended travel restrictions and bans at that point, who pointed that perhaps the measures were a little too harsh. The nationwide lockdown as we all know was imposed on the 24th of March, with 536 cases whereas Italy imposed it on the 9th of March when it had a sum total of 9172 cases! In doing so, we have managed to stay ahead of the curve. The graph given below demonstrates just how effective this has been.




But we are under lockdown now, for over 8 days, and the implementation is pretty good. Why are the number of cases still increasing then? Does that mean that the lockdown has not worked?


Since it has been less than 14 days for the lockdown, the people presenting to the hospitals now, are the ones who were infected before the lockdown was implemented. These numbers are representative of all those that were either advised home quarantine initially and did not follow it, or those that were asymptomatic when they were quarantined and have not infected others. It does not mean that the lockdown has not worked. The effects of the lockdown will be seen 14 days later. So, 14 days after the 24th of March, or 8th April onwards, if you see a dip in the number of cases, the lockdown will have worked.


Now that everyone is sitting at home, is there a way in which we can flatten the curve further?


Yes, we can! We can adopt a few more measures to reduce transmission.

  1. Do not leave home unless it is necessary.

  2. Even if you do leave home to buy something, ensure that it is only one person who goes each time.

  3. When out buying essentials, maintain social distancing, ensure that others follow social distancing too. Do not be afraid to call out those who are not doing so.

  4. Do not touch objects unnecessarily.

  5. Once you leave the sanctity of your home, you are forbidden from touching your face again.

  6. When you do get back, wash yourself or bathe to ensure, that the virus does not gain access to your house.

  7. Everything that is bought and the bag that was used to carry it all, needs to be washed clean.

  8. Try and minimise he number of times you leave the house to reduce your exposure to the disease.

What do you do when you fall ill during the lockdown, with either Covid or a non-Covid illness?


During this period of being locked down at home, it is entirely possible that you or your loved ones fall ill, with any illness, not necessarily Covid. A health emergency is likely at any point.

  1. Call you doctor or the nearest hospital to inform them about your symptoms.

  2. If it is an ache or a pain or something that can be resolved by a telephonic conversation and a prescription, do that. REMEMBER, HOSPITALS ARE WHERE THE SICK PEOPLE ARE – WHERE THE COVID INFECTED ARE. A trip to the hospital, warrants an unnecessary exposure to an already ill patient, whose immunity is weakened and their loved ones who come to the hospital as attendants.

  3. However, if you do have a medical emergency, do not neglect it by any means, you can take due precautions to prevent infection and go to the hospital safely.

  4. The patient should be accompanied by just ONE healthy attendant to reduce the risk of infection.

  5. When going to the hospital, do wear a mask or tie a scarf around your nose and mouth.

  6. Refrain from touching anything in the hospital, railings, tables etc, even if they look clean!! The hospitals are trying their hardest to sanitise between two patients, but why take the risk?

  7. If you do have Covid-like symptoms; DO NOT PANIC.

- Isolate yourself in a room.

- Arrange to call the Covid helpline number (list given below) so they can direct you to the nearest isolation facility where you will be seen and treated.

- Try and recollect a list of your close contacts who could possibly also have the infection, in case you do test positive.

- One extremely important thing to remember is, a lot of illnesses have Covid-like symptoms but are not Covid. But until you know for sure, it is best to isolate oneself and protect your loved ones.

With our population of over 1.3 billion under lockdown, travel bans in place and the administration trying to increase the number of facilities available for testing, quarantine and treatment, we have the right tools in our hands to be able to minimise our losses due to widespread Covid infection. All we have to do, is play our part. Maintain social distancing, stay home, convince others to stay home, report those with symptoms and hope for the best outcomes.

Stay home

Stay safe, stay healthy

Help Flatten the Curve…

We can and we will beat this!




Guest Blog Credit :

Dr Gauri Raman Gangakhedkar Anaesthesiologist, Researcher KEM Hospital, Mumbai


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