As waves of the Corona virus keep hitting India, the pandemic unleashed by the virus, effectively, follows the classical pattern of communicable disease dynamics. During the first wave while one thirds of the below poverty line population encountered the natural infection, the remaining bulk of the affluent citizens of the country who could afford to stay back at home, remained vulnerable, and formed the critical mass for the second wave.
The Indian CoViD-19 experiences continue to spring surprises. Last year experts had predicted catastrophe for India. In the first week of May 2020, when deaths from CoViD-19 per million population in the USA and European countries ranged between 200 to 500 per million population, the death rate from CoViD-19-19 in India was just 1 per million. The low figures of mortality were also seen in other Asian and African countries[1].
Alongside CoViD-19 taking a mjor toll on India, an alarming number of fungal attacks by mucormycosis known as the “black fungus” also plagued the country. (Picture Courtesy: Getty Images)
Various reasons were postulated for the low impact of the pandemic on Asian and African countries, such as lower rates of obesity, younger age profile and cross immunity due to infections with other coronaviruses in densely populated developing countries.
By 1 August, 2020, India had cumulative deaths of 26 per million population, still far behind the Western countries. The first round of national level serosurvey undertaken by the Indian Council of Medical Research (ICMR), revealed that almost 1 crore Indians had encountered the novel coronavirus[2]. The most encouraging estimate from this serosurvey was that the infection fatality rate worked out to be 0.08%, implying that 99.99% of those who had the natural infection recovered from it.
The first wave peaked in India around September 2020, barely touching a daily total of 1 lakh cases, and around 1200 daily deaths. By end of 2020 and around the beginning of 2021 it appeared that the pandemic has receded in India. Around this time, the third round of serosurvey by ICMR revealed that about 21% of the population have IgG antibodies to the novel coronavirus[3]. And after this third round of national level serosurvey, the estimated infection fatality rate for Indians worked out to be 0.05%, given that the survey indicated that about 30 crores in India had encountered the virus and a cumulative fatality around 1.5 lakhs at this point of time.
However, March 2021 onwards, cases spiked sharply, and so did deaths. Within a very short time, the cases peaked around first week of May 2021 with over 4 lakhs daily cases. Most distressing were crises of hospital beds, ICUs and oxygen. The heat was on, and the dust blinded the vision of experts. Blame game started.
Just when complete collapse of the health services seemed imminent, number of daily cases started a rapid decline and by end of May 2021 daily case count came down well below 2 lakhs per day. The Indian CoViD-19 enigma never fails to surprise one and all.
What is the explanation for such twists and turns?
The role of vaccines could be excluded at this point with less than 3.5% of the population being fully vaccinated presently. One has to go back to basics of epidemiology and immunology to search for answers.
The pandemic is following the classical pattern of communicable disease dynamics, which was interrupted by measures such as lockdowns. Restrictive measures cannot eliminate community transmission once it is established. Our team carried out a serosurvey for IgG antibodies among a population of 25 lakhs in Pune District of the west Indian state of Maharashtra, the frequent epicentre of CoViD-19 in the country[4]. The study coincided with the steep fall in daily cases after middle of September 2020. Findings and inferences from this study can to some extent explain the dynamics of the pandemic in most parts of the country.
In the first wave, about 30-35% of the studied population had encountered the natural infection. These were mostly the working class at the lower level of the economic spectrum mostly living in slums and tenements. In some of these pockets the seropositivity to IgG antibodies reached almost 70-80%. On the other hand, the middle and affluent class housing societies had far less seropositivity levels some as low as 5-10%. These were the more privileged people who could afford to work from home and were religiously observing “covid appropriate behaviours”. These measures definitely help in the short term, but are difficult and unnatural to sustain in the long run.
At the end of the first wave the transmission was sharply brought to halt by these two factors, i.e. the immunity due to natural infection among the less privileged and the “covid appropriate behavior” among the more privileged. However, the latter remained vulnerable and being the bulk of India’s population – about 70% – formed the critical mass for the second wave.
Lulled into complacency, this critical mass of vulnerable people started mixing and taking part in all social activities giving rise to the sudden peak. To some extent this might also have been facilitated by the more contagious, but less virulent strains causing more widespread infections. This while overwhelming the hospital services might have also led to almost 30 times more undetected infections which must have elevated the population level immunity and caused the equally sudden fall in cases. Such phenomena suggests that in densely populated countries like India, natural infections will contribute more towards population level immunity better known as herd immunity, vis-a-vis mass vaccination, given the logistics and challenges to roll out vaccination to a large population. A more prudent approach would be to go for focused vaccination for vulnerable groups and frontline workers instead of mass vaccination.
Rapid population level serosurveys after the dust of the second wave settles, in different parts of the country, can give an accurate picture of the population level immunity. This besides enabling prediction of future waves, can drive rational vaccination strategies.
The disturbing trend CoViD-19 second wave leaves behind as it beats a retreat, are the gaping fault lines in India’s public health infrastructure.
While second wave seems to be receding, there are some disturbing events associated with it. In the second wave we were overwhelmed by sheer numbers and not by the lethality of the virus per se. It exposed the fault lines in our public health infrastructure and inequitable distribution of health services. Corporate model of health care concentrated in the big cities was ill-equipped to cope with the second wave as it affected second tier cities and large parts of rural India with insufficient public health services. For the poor in India access to quality health services is a day to day challenge. Out of pocket expenditure for treatment drive many poor families below the poverty line. Because of the mismatch of supply and demand, the common man during the second wave faced the grim situation of lack of adequate medical care which was being faced by the poor and marginalized all these years.
The alarming number of cases of mucormycosis or “black fungus” following the second wave also points towards the deeper malaise of lack of equitable health services in the country. This usually rare fungal infection occurs in people who have severe uncontrolled diabetes, have deficiency in immunity due to various causes, are on steroids which can cause immune suppression and increase in blood sugar levels.
India has the dubious distinction of being the diabetes capital of the world. Studies in our urban as well as rural field practice areas have revealed a large number of people with risk factors for diabetes as well as frank diabetes[5, 6]. Lifestyle changes have reached rural India as well with prevalence of diabetes reaching levels seen in urban India. What was most concerning was that half of the young diabetics in the 35-45 age group were not aware of their diabetes status.
Against this background, it is likely that after recovery from CoViD-19, due to undetected, and inadequately managed diabetes with some immune deficiency due to the viral infection and heavy dose of steroids, such patients fall victim to potentially threatening fungal infections.
To conclude, India needs to develop equitable health services across both urban and rural India to cope with present and future pandemics.
References:
- Banerjee A. COVID-19: The curious case of the dog that did not bark. Med J DY Patil Vidyapeeth 2020;13:189-91
- Ray S. Coronavirus Infection: Around 1 Crore Indians were exposed, SeroSurvey Finds. Financial Express; 2020. Available from: https://www.financialexpress.com/lifestyle/health/coronavirus-infection-around-1-crore-indians-were-infected-sero-survey-finds/1988886
- Banaji M. Covid-19: What the third National Sero-Survey Result Does and Does Not Tell Us. Science. The Wire. Health; February 05, 2021. Available from: https://science.thewire.in/health/thirdnational-seroprevalence-survey-icmr-covid-19-rural-prevalence-testpositivity
- Banerjee, Amitav and Gaikwad, Bhargav and Desale, Atul and Jadhav, Sudhir Laxman and Bhawalkar, Jitendra and Salve, Pavan and Dange, Varsha and Raut, Chandrasekhar and Rathod, Hetal, SARS-CoV-2 Seroprevalence Study in Pimpri-Chinchwad, Maharashtra, India Coinciding with Falling Trend – Do the Results Suggest Imminent Herd Immunity?. Available at SSRN: https://ssrn.com/abstract=3736159 or http://dx.doi.org/10.2139/ssrn.3736159
- Rathod HK, Darade SS, Chitnis UB, Bhawalkar JS, Jadhav SL, Banerjee A. Rural prevalence of type 2 diabetes mellitus: A cross sectional study. J Soc Health Diabetes 2014;2:82-6.
- Banerjee A, Rathod HK, Konda M, Bhawalkar JS. Comparison of some risk factors for diabetes across different social groups: A cross-sectional study. Ann Med Health Sci Res 2014;4:915-21.
AMITAV BANERJEE has experience of control of epidemics at different locations of the country such as outbreaks of pneumonia, hepatitis, typhoid, German measles, food poisoning and tribal malaria. https://www.youtube.com/watch?v=bZOWByfbYNY . He can be reached at amitavb@gmail.com
Opinions expressed in this article are of the author’s and do not represent the policy of The Edition. The writers are solely responsible for any claim arising out of the contents of their articles.
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