Disclaimer – This article is mainly a hypothesis generating scientific review. The only proven and effective way to stop the corona epidemic is to follow the orders and advises being periodically released by the Government such as lockdown, social distancing, hand washing, isolation etc. Let there be no complacency in that.
Prof Pankaj Chaturvedi, Deputy Director, Centre for Cancer Epidemiology, Tata Memorial Center, Mumbai
Dr Akshat Malik, Fellow, Imperial College, NHS Trust, London
The recent corona virus (COVID-19) pandemic has brought the world to a standstill. Irrespective of the geographical location or the economic might of a country, all have been impacted without discrimination. In a matter of few months, worldwide over 600,000 people have been infected and over 30,000 people have lost their lives to this virus.
The Government’s decision of lock down, hand wash, social distancing, quarantine etc. are very prudent steps that must be complied to. Compared to several European countries, India had started screening passengers and restricting air travel much earlier on. It is understandable that being such a vast and populous country, it is not easy to restrict movement and behavior of the people. Without any doubt, the pro-activeness shown by the Government will help in reducing the case load and subsequent fatalities. Let there not be any complacency in following the Government’s periodic advisories and orders. That is the only way most of the countries have curbed the corona epidemic.
India is considered as hotbed for any type of infectious disease. Overcrowding, poverty, ignorance, illiteracy, low standards of personal hygiene, poor health infrastructure and poor public sanitation all contribute to spread of any such disease. India is not untouched from the virus. However, as of today, the intensity of the impact witnessed by other countries has not been the same in India. This can be judged by the fact that as of 29th March 2020, India has had just over 1000 positive cases, with only about 25 deaths. Whether this signifies a reduced severity of COVID in India, is contested by several skeptics including us. It is likely that India has not been testing enough like the western world. In that case, the severity of the infection would be judged by the fatalities, which without doubt have been surprisingly low. There have been several explanations, which have been doing rounds on various social media platforms. These range from consuming spicier and hot food compared to other countries to low level of hygiene and sanitation giving rise to higher herd immunity amongst Indians. These currently do not have any scientific backing and it will be very difficulty to actually test their applicability. In this article, we have tried to look into various parameters that predispose to spread of corona virus. We also looked at various factors that possibly explain lesser severity of COVID 19 in Indian subcontinent. We acknowledge that it may be too premature in reaching to this conclusion while peak infection is still to happen in this part of the world.
Coronoa virus is not the first global epidemic that India has witnessed in this millennium. The Bird or Avian flu outbreak in Asia Pacific region, presented as Severe Acute Respiratory Syndrome, started in the winter of 2002 from southern China. India reported its first case of bird flu in April 2003. The total number of cases reported during the global pandemic were at least 8098 (from November 2002 to July 2003). While deaths due to Bird Flu in China and Hong Kong were 640, India reported 3 confirmed cases but no deaths.
The Influenza outbreak (H1NI) famously known as Swine Flu started from central Mexico in 2009 and spread world over. The total confirmed deaths attributed globally to H1N1 were around 20,000 where as 6 million were infected worldwide. India imposed strict surveillance of travelers from abroad and other measures to contain the spread. By March 2010, India reported 20164 cases with only 1444 deaths. In this pandemic, USA, Brazil, Europe and China remained the most affected geographic regions.
The period of 2014 -2015 witnessed an epidemic of Ebola Virus Disease starting from West Africa to Europe and then spread to rest of the world. This virus has fatality rate of more than 50%. While 11,315 people died globally, with proactive efforts of Government of India, no death was reported from Ebola virus disease in India. Skeptics may attribute it to under-reporting and lack of facilities for viral testing. However, in the recent times easy availability of diagnostic tests and Government’s emphasis on reporting of such cases is a valid counter argument for the skeptics.
This brings us to a very pertinent question – Are people living in India truly resistant to viral epidemics? We will try to address this in three headings – Agent (Virus), Host (People living in India) and Environment (of Indian Subcontinent).
Researchers have done the genomic analysis on the virus genomes obtained from positive patients in India, Italy, USA, Nepal and Wuhan. They found unique mutation in the Indian strains not found in others making our virus different from others. They also found few host mi-RNA which could target the viral genes specifically, of these one of the mi-RNA was found to be specific to the Indian strain. Chinese researchers have also found that there are L and S type of strains; L type is believed to be more prevalent and aggressive than S. We currently lack information about which one is the dominant strain prevalent in India.
Coming onto the host factors, it has been seen all across the globe that COVID-19 infection is more severe in elderly as well as in people with co-existing morbidities. Italy has probably been hit so hard because nearly a fourth (23%) of its population is above 65. Indians are much younger in comparison and above-65 constitute only 6.5% of the population. In younger individuals, the viral infection has not been that harsh and majority of individuals are able to recover quite easily without any incapacitation.
Studies from China and abroad have reported that tobacco smoking/vaping predisposes to not only corona virus infection but also subsequent mortality. Smoking rate in China, Italy and USA are 21%, 14% and 15% whereas in India it is 9%. It has been observed in all worst hit countries that COVID-19 affects and kills more men than women (3 times more). One of the explanations for this male predilection is higher smoking and alcohol consumption in men compared to women. These habits are also the established causes of Hypertension, Coronary artery disease, Pulmonary diseases etc that are known to increase the fatality rate of COVID-19.
It is worth mentioning that, traditional Indian Namaste (greeting with folded hands) has emerged as a healthy alternative to western style of handshakes and peck on the cheek.
Malaria and Tuberculosis have been bane for India since ages. Will these turn out to be beneficial in protection against COVID-19? BCG, is a vaccine used to protect against tuberculosis. It has been found that it may have immune modulatory effects and may provide protection from other pathogens too. Currently, there are trials underway in Netherland as well as Australia where researchers are assessing if the BCG vaccination would provide protection from the corona virus infection or at least decrease the intensity of the symptoms. BCG is a part of the national immunization scheme and vast majority of Indians have received it already.
Very recently there has been a lot of media attention on the use of hydroxychloroquine for prophylaxis against COVID-19. There are few studies which are currently underway to assess its utility in treating such infections. The apparent lack of cases (at least initially) in the malaria-endemic regions brought out a thought process that probably people staying in these regions may be resistant to coronavirus. Few hypothesis regarding this included – heightened immunity in such individuals, genetic/molecular changes which predispose to malaria may increase resistance to cornona virus. Unfortunately, at present these just remain as theories with no firm scientific backing for these. Moreover, of-late cases have been increasing in the ‘malaria-endemic’ regions thus questioning the validity of such theories. Needless to say these have not been disproved either.
It is also believed that exposure to multitude of infectious diseases since childhood results in development of innate immunity which may help ward of diseases like COVID-19. This has been noted in form of reduced number of cases of other corona virus related epidemics. This is debatable because, as a community we are still vulnerable to several other viral infections.
We would like to divide the environmental factors as natural and induced. Natural environmental factors include the temperature of the area . It has been shown through multiple studies that corona virus does well in cooler temperatures and probably its transmission is also conducive. This is supported by the fact that majority of the worst hit regions are geographically cold temperature areas. Corona viruses are enveloped by a fatty coat studded with protein spikes giving appearance of a crown or “corona” in Latin. Due to this heat sensitive fatty envelop, virus cannot survive outside the body in hot weather for a long time. Therefore its transmission is reduced in hot weather. In fact, affected countries have been attempting to delay the peak of the disease to summer!
There are other ways how the famous Indian summer may come to our rescue. Corona viruses are also susceptible to UV rays that are easily available because of the clear skies and bright sun. There are some reports that suggest that the vitamin D levels may dictate our vulnerability to all infectious diseases including corona virus. During the winter period, lack of exposure to Sun and protective clothing results in lower vitamin D formation compared to summer.
Humidity is also known to predispose to COVID-19. Dry ambient air reduces the amount of mucus coating our respiratory passage leading to our lungs. Mucus, a sticky secretion of our respiratory system, provides a natural barrier against bacterial and viral infections. Study of patterns from China suggests that deaths from COVID-19 were lower during the days when the humidity levels and temperatures were higher.
Though the possibilities discussed above may indicate that Indians may escape the fury of COVID-19, we will come to know the actual impact in the next few weeks. At this point, let’s not get swayed by these theories and do our best to stop the spread of corona virus by following the directives of the Government of India.