Fifth week of the Lockdown in India

The lockdown commenced on the 23rd of March 2020 in India. We are now in the fifth week of confinement and beginning to wonder when does this end. No one seems to have a clear answer whether the virus will become endemic or will have a definite containment date. 

In continuation of articles written earlier, I will give a few charts to give the reader a sense of the proliferation of the SARS-COV2 virus in India and the comparison with the rest of the world. The methodology has been explained in the previous articles and is accepted statistically. The representation here varies as the choice of the period for data analysis is 5 day cycles and averaging of the rates involved. 

           

Figure 1 - COVID 19 Proliferation in India 

The average rate of transmission of the virus in India is 1.86. It indicates that the disease is growing within India at a slower rate than earlier. According to ICMR, 80% of the cases being found in India are asymptomatic essentially implying it is hard to trace and track the disease within the population. The Mortality rate is 2% of the total number of infections detected. The total number of infections stood at 17,265 and the number of deaths at 543 on the 20th of April. 

Figure 2 - Global Transmission Rate Comparison

(Primary Data Source - WHO) 

While comparing the average transmission rate of India with other highly affected countries it was observed that the only other country with higher transmission is United States with an average transmission rate of 2.11. Highly affected countries where the disease is still proliferating are Spain (1.85), Germany (1.80), UK (1.58) and France (1.26) in the comparable nations set. 

The Global average transmission rate stood at 0.402 with the total number of cases at 2,314,621. In the comparable nations set, there are three countries where the disease is not proliferating rapidly, Iran (0.906), Italy (0.795) and China (0.005). 

India is relatively better off in the total number of cases it has had to deal with compared with developed nations. The highest number of cases by the 20th April were witnessed by United States at 723, 605 followed by Spain (195,944), Italy (178,972), Germany (141,672) and France (111,463). 

It is notable to mention and also visible from the trendline above, the Global and comparable nations average over the last ten days has been under 1. This essentially means a slowdown in the growth of the disease. The disease maybe slowing down but the number of cases is cumulatively increasing. 

Figure 3 - Global Mortality Rate Comparison 

(Primary Source Data - WHO) 

The Indian average mortality rate (2%) compared with the Global average of 4.96% is lower. Within the comparable nation set of highly impacted nations, Italy has the highest average mortality at 9.88% followed by France (8.08%), Spain (6.82%), UK (6.88%) and Iran (5.89%). These nations have the average mortality rate higher than the global. The reason for such high rates can only be understood in time due to comorbidities or other short comings in treatment. 

India has a relatively low mortality burden at the moment comparable with Germany (1.15%) and United States (3.22%). The mortality rate in China has stablised at 4.12%. A recent spike in cases was noticed in China due to adjustment of deaths that were not accounted for earlier due to one reason or another. 

In absolute numbers, the total deaths across the world stood at 157,847. The highest number of deaths, even with a low mortality rate, has been witnessed by United States at 34,203. This is followed by Italy (23,660), Spain (20,453), France (19,689) and UK (16,060). China (4,642) and Iran (5,118) have comparable number of deaths. Even with a relatively higher number of transmission cases, Germany is an outlier with a lower mortality rate thus few deaths at 4,404. 

It is remarkable to observe that even though the average transmission rate is declining, the average mortality rate is increasing in the comparable nations set with the exception of China and Iran. 

In summary, the world has been gradually containing the proliferation of the virus in various communities. We may have temporarily slowed down the viral movement with simultaneous lockdowns across the world, we have not been able to find a cure or a vaccine that provides adequate protection. 

As the world braces for reopening no matter how gradual, we will witness a spike in transmission rates and mortality. The greatest fear is the return of viral transmission in autumn similar to the 1918 Spanish flu pandemic. The pandemic took the largest number of lives during that winter. India had the worst fatal loss of life in the world through the winter of 1918. 

We must remember the lessons from history. All we can do at this stage is to prepare as intensively as we can for when the healthcare system will be overwhelmed with cases. In a highly populated country such as India with very dense urban enclaves, it will be a tremendous challenge. Thus far rural India has not been as impacted. Our Achilles heel is our weak primary care system and healthcare capacity in rural parts of the country. 

The social cost of exposing a large population in developing herd immunity to the SARS-COV2 virus will be just too high. Until such time a vaccine can be a viable measure in 2021, we must prepare for at least a year of social distancing measures, a graded opening plan for the economy and keeping healthcare capacity mobilised. 

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Continuation of the Corona Lockdown - A case study of highly impacted nations

There is a significant amount of discussion across India whether the government should continue with the national lockdown, the degree and scale of the lockdown. Following the imperative to save lives, the timely decision to implement the lockdown certainly stemmed the transmission rate in India. The unthinking obtuseness of a few has led to rapid proliferation in specific hot spots. 

In this article, I am aiming to draw conclusions about the continuation of the lockdown in India based on comparison of the transmission rate and the mortality rate of the patients who have acquired the SARS-CoV2 virus in their bodies. The rates being compared are those of the 8 nations that have had the highest proliferation and mortality. The highly impacted country transmission and mortality rates were compared with the Global and India average rates to draw conclusions. 

The methodology used has been the same as that mentioned in the previous article. The source data for countries such as USA, UK, Italy, Spain, France, Germany, Iran, China has been analysed. The figures were analysed in 8 five day periods starting from 1st of March (1/03 to 06/03) until the 10th of April. The source of this data is the report generated by the Disease Surveillance unit of the World Health Organisation. The data used for India are similar 5 day periods only a day earlier, 29th February till 4th March cycle. The figures are averaged for the 8 periods therefore are comparable. The output has been analysed and presented in the figures below. 

Figure 1 - COVID19 Transmission Rate Comparison of Highly affected countries with India 

(Primary Data Source -WHO)

The transmission rate of India compared with rest of the highly impacted nations and the global average clearly demonstrates that India (yellow line above) is the only country in this data set for which the last 10 day average is higher that rest of the nations. The average Indian transmission rate is 2.16. Infact the rate of transmission for the last five day period is 0.9. It has been consistently higher than all other highly impacted countries over the last 10 days as shown in the chart above. 

During the last 40 days, the average transmission rate is observed to be the highest for USA (2.558) followed by Spain (2.282), Germany (2.215), India (2.160) and UK (1.881). Other countries that are highly affected are France (1.542), Iran (1.104), Italy (0.965) and China (0.005). The Global average transmission rate is 0.444. The transmission rate effectively implies the unbroken chain of pandemic transmission from one person to another. Figures less than 1 imply a break in transmission of the pandemic virus.

The most notable number is that of China where the rate of transmission is consistently extremely low over the period compared. China recently exited the Lockdown after flattening the curve and staying at that level for several weeks. The average transmission rates are noteworthy for countries such as USA, Spain, Germany, India, UK and France that are beginning to see explosive proliferation.

Countries such as Germany which had a very large spike in transmission like India in the first week of March have gone on to have very large number of cases. USA, Spain and Germany which have high number of cases have managed to bring down the transmission rate under 1 by the first week of April. 

India has effectively observed a periodic upturn and followed by control in infection transmission. During the last five days, the transmission rate appeared to have come down to 0.9, this may increase in the month of April as the government increases the testing effort. 

USA has crossed 425,000 cases while Spain (152,446), Italy (143,626)  and Germany (1,13,525) stand are at a distant second, third and fourth with infected patients and overwhelmed healthcare establishment. These countries have far exceed the number of infections in China (83,305) which was first nation to be seriously impacted. The vast difference in numbers can clearly be attributed to the strict and intense lockdown China undertook. It has successfully flatted the curve for transmission of infections.

The average transmission rate of India is comparable with USA, Spain and Germany. Spain and Germany have flattened the transmission curve in the last 20 days, while USA has commenced the flattening over the last 10 days. Other highly impacted countries France and UK have started flattening the curve over the last 15 days. Even though Italy had high proliferation in the population, it has brought the transmission rate down over the last four weeks. Even Iran after an initial spike in transmission has brought the transmission rate under control. 

The most remarkable flattening of the curve is of course in China. It has consistently kept the transmission rate low over the last 6 weeks before it chose to open the lockdown. It is encouraging to note the global transmission rate climbed up and again has flattened over the last 2 weeks. From the data, it evident that nations which have locked down to flatten the transmission curve and maintained it for several weeks, have been able to contain COVID-19 disease through public management. 

Figure 2 - COVID19 Mortality Rate Comparison of Highly affected Nations with India 

(Primary Data Source - WHO)

The Global average mortality rate derived from the data over the last 40 days is 4.53% of the total infections. The highest average mortality rate has been recorded in Italy at 9.06 %. This is followed by France (5.86%), Iran (5.8%), Spain (5.8%) and UK (5.29%). Countries below the global average mortality rate are China at 3.97%, USA at 2.9%, India at 1.7% and Germany at 0.71%. 

It is remarkable to note that USA despite over 425,000 cases has kept the rate of  mortality low with respect to other highly impacted nations. Two countries that stand out in the data set are India and Germany. The number of infections in India is almost two orders of magnitude less than USA, Italy and Spain at this stage. It is at least an order of magnitude less that other comparable nations in this data set. The average mortality rate of India is 1.7% is the second lowest in the data set. 

The most remarkable study is that of Germany where the derived average mortality rate is only 0.71%. It is the lowest in the comparable nations mortality rate even though it has been climbing gradually since 1st of March. The number of cases of transmission are relatively high at 113,525 at an average transmission rate of 2.2. It stands fourth in the absolute number of COVID19 cases higher than China and third in the average rate of transmission. Yet it has managed to keep the mortality rate very low. It speaks volumes of the clinical management of the hospitals in the country. It is a cause of hope for rest of the world. Germany may perhaps be one of the national populations that may develop herd immunity. 

It is also note worthy to mentioned that the Global average mortality rate has been climbing over the last 40 days. The rate for the last 5 day period stands at 6.1%. Four countries in particular have witnessed very high mortality rate in the last 5 day period, France at 14.28%, Italy at 12.73%, UK at 12.26% and Spain at 10.00%. All of these countries have witnessed an increase in mortality rate over the last 40 days. Even those these countries have started to flatten the transmission curve and reduce the number of new cases, the average mortality rate has been climbing. 

The mortality rate of other highly affected countries such as US had a large spike (6.76%) at the start and it has gradually decreased in all of March. It has started climbing steadily again in April. Even at that, the average mortality rate remains low at 2.9% in the comparable nations set. 

Iran is the only trendline exception in the entire set, it has the third highest average mortality at 5.8%. The mortality rate sharply climbed and it has gradually decreased over the last 10 days. The absolute number of deaths is effectively more than that of China at 4,110 deaths on the 10th April, even though infection cases at yet to reach the same high. The average transmission rate in Iran is much higher (1.104) than that of China (0.005) for the comparable period. 

The mortality rate in China has been consistent for the last 40 days averaging at 3.97% of the transmission cases. To give a sense of comparison with India, on the 10th of April, the cumulative deaths in China stood at 3,345 and total infections at 83,305. India has 199 deaths for 6,412 infections. The mortality in India is almost one order of magnitude less than that of China. The mortality rate has flattened in China, it is on the increase in India. While both countries have comparable populations, the health systems have entirely different capacity. It remains to be seen whether the number of infection cases and deaths in India will rise to similar proportions. 

Therefore in being able to decide on the extension of the lockdown, we must critically see the data from other comparable nations. Factors such as flattening of the transmission and mortality curve are not consistent. While the transmission curve may be getting flattened, the mortality curve may keep rising.

The only evidence of a Lockdown exit is from China. It was the first to be highly impacted and it managed to flatten the curve of both transmission and mortality. The country also managed to keep it flat for at least 4 weeks before it came out of the lockdown. 

India must pay heed to the evidence from other countries, its average rate of transmission is  the fourth highest in the world, it should continue to remain in a state of national lock down for atleast another 4 weeks. It may consider an extended lockdown for 6 weeks till the end of May to ensure the complete flattening of both the transmission and mortality curve. 

The goal must be to reach an average transmission rate of less than 0.1 and stay at that level for 3 weeks before we can comfortably open up. India's average mortality rate is currently 1.7% but with better clinical and hospital management it can be brought under 0.5%. 

The extended Lockdown would no doubt impact the economy, livelihoods and sustainability especially at the bottom of the human pyramid. The government must announce further measures to care for those who are the weakest. Only then we could emerge from this grave hour of national and global crisis with our head held high. We are still 8 weeks away from when we can conclusively say India is in the safe zone and ready to return to normalcy. 


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Corona Pandemic Transmission in India

While the world has been witnessing rapid transmission of COVID19, cases in India have only started to increases towards the end of March. This is largely due to inward flow of people flying back from Asia, Europe and North America. 

Large numbers of people have quietly made their way into the metro cities and smaller towns from overseas following a spike in cases just before the lockdown. Following the lockdown announced in India just over a week ago, the migrant labour also started to rush back to villages in packed trains and buses, while many walking back hundreds of kilometers. 

At this stage, no one has a clear estimate of the transmission rate happening within India. A lot has been written about it but no real attempt has been made at forward projections of transmission of infections, resulting hospitalisations and mortality within the population. 

My objective in building a simple mathematical model based on existing facts is to understand the transmission of the virus in the population, the number of people who would end up in hospitals and those we would unfortunately lose in the battle against Corona virus. 

I have made some very basic calculations from the rate of change in transmission of the infection globally and in India. The second data set, I have used is the number of deaths both globally and in India. The primary data has been sourced from World Health Organisation. 

My methodology involved assessing the March data of patients and mortality. Analysing it over a 5 day period and calculating the growth rate which I then average to get the base rate for projecting the transmission in India over the next two months. 

My findings are shown in the figures below and explained.  

                     
Figure 1- Global Transmission of COVID'19 Infection during March '20

There has been an exponential growth of patients globally suffering from COVID19 during the month increasing from 87,137 infected on the 1st of March to 6,93,224 infected on the 30th March. The corresponding increase in mortality in this period was from 2,977 deaths on the 1st of March to 33,106 deaths on 30th of March. 

Performing calculation over a 5 day period in the month of March, this yielded an average infection transmission rate of 43.4% and an average mortality rate of 4% in patients suffering from COVID19. These rates would differ if examined in greater granularity by world region, demographics and conditions. 

It is remarkable to note that the transmission rate grew consistently over the period of March while slightly slowing down in the last 5 days. The rate of mortality grew from a low of 3.4% to 4.8% in the last 5 days of March. There would be much to debate on the causal factors for these numbers. The pandemic epicentre was China early March and has gradually moved Westward later in the month. 

Figure 2 - COVID19 Transmission in India during March '20

The case of infection transmission in India is radically different to that of China for the month of March. India had reported only 3 infections on the 1st of March which has dramatically multiplied to 1,071 on the 30th of March. This corresponds to a 5 day average period of transmission of 237%. In other words, a transmission factor of 2.37 per patient, that is the number of new cases arising from transmission from an existing patient. 

Various agencies have derived rates differently. Indian express took a factor of 1.7 while most other modellers are using various numbers between 2 and 3. In the viral stage of transmission this rate will be much higher that what most modellers are using. Therefore the estimate remains conservative.

The mortality rate in India last month is by far negligible as compared with other highly impacted COVID19 countries. It was zero death on the 1st of March and has grown to 29 deaths by the end of the month. This corresponds to an average mortality rate of 2.1% calculated over 5 day periods for March. That effectively means 21 deaths per 1000 cases of transmission. The mortality rate in India is nearly half of the rest of the world. This is very likely to increase as we start to progress through stage 3 of the pandemic in India. 

It is notable to mention that our transmission rate is higher than the global average for the same period while our mortality rate is lower. This may imply that more people will be infected than those who will succumb to COVID19 it as compared with rest of the world. 

                        

                        
Figure 3 - COVID19 Projected Transmission during the period of March '20

The transmission projection begins with a base figure of infections as they stand on the 1st of April that is 1250 cases. A transmission rate of 2.3 has been used for cumulative progression over a 5 day period. The projection was calculated up to the 30th of May. This is anticipated to be the most intense growth of COVID19 infections in India. A peak of 3,92,54,565 infectious cases has been projected if there is no break in the cycle of transmission. A conservative transmission rate has been estimated compared with other modellers given the high density of population and demographic spread. 

The unbroken infection chain if not adequately checked will explode towards the end of April resulting in a huge number of people infected in the community. Explosive and exponential growth of infections will occur should strict social distancing norms not be followed. 

                     
Figure 4 - COVID19 Projection for hospitalisation and critical care in India

The projection for hospitalisation and critical care requirement for COVID19 patients is based on the derived rate of transmission of infections as shown in the previous chart. Two other assumptions based on international practises in modelling have been included. The first assumption is that 15% of the transmission cases will require hospitalisation. The other factor is 5% of the total cases will require critical care at hospitals. 

The figure 4 above shows an exponential growth through rapid community transmission. An unbroken transmission chain would result in cumulative hospitalisation of 58,88,185 patients infected with COVID19 by the end of May 2020. The sub-set of the admitted patients requiring critical care would rise to 19,62,728 by the end of May 2020.

Both these are staggeringly large numbers and our healthcare system is ill prepared to deal with the overwhelming requirement. The unbroken chain of transmission of the virus would result in tremendous stress on the health care infrastructure. The stress is expected to increase between the first and the second week of May. The system would be overwhelmed thereafter and will require extra resources to cope with the growth of critical patients, thereby implying new critical care field hospitals should be designed and commissioned. The preparation for which should begin in earnest now. 

             Figure 5 - COVID 19 Projected Mortality in India 

The projection of mortality from COVID19 has been based on the derived mortality rate from March and base number of 32 deaths on the 1st of April. A mortality rate of 0.021 has been applied. An exponential growth of morality in COVID19 patient cases is expected to correspond to the increase in hospitalisation of infected patients. An unbroken rate of transmission of the virus would sharply increase the mortality between the first and second week of May. 

There are a whole host of causal factors that may change this rate of transmission and improve the rate of recovery. The most vulnerable will be the elderly, children, pregnant women, adults suffering from malnutrition and patients with other non-communicable diseases. Preventive measure such social distancing, hygiene, sanitation, testing and containment of patients, availability of personal protective equipment, disciplined clinical management, and limiting relapse in patients. The long term defence is of course a vaccine which may not be available for another 18-24 months. 

We can only hope to avoid this scale of tragedy in India by breaking the chain of infection. This requires a very serious commitment by the entire society. We must entirely avoid any kind of congregation where multiple social interactions can take place. We must take due care in maintaining high level of hygiene and sanitation in our immediate environment. 

In the absence of a strong healthcare system, our only hope of averting a catastrophe is by limiting the transmission to under 3% of our national population of 1.3 billion (130 crore). The transmission chain is expected peak in May 2020. The peak may come sooner should we conduct ourselves in a discipline manner. The containment of COVID19 is expected to start from June. Until then all of us must play our part in protecting everyone else. The combination of providence and human effort may save us from tremendous collective pain. 


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