As the world freezes, paralysed and petrified by COVID-19, the question needs to be posed as to who are its co-conspirators? Does the virus kill most of its victims on its own or does it collude with other killers to launch a lethal attack on human bodies? Unless we lay bare all the elements of this plot, we will be unable to provide a clear and comprehensive response that helps us to prevent similar threats in the future.
Every country that has reported a number of fatalities has stated that the deaths are most numerous among the elderly and those with co-morbidities or co-existing health disorders. Which are these? Most often, they are hypertension, heart disease, diabetes, chronic respiratory disease, kidney disease or persons with cancer, especially those on immunosuppressive therapy. These are known as non-communicable diseases (NCDs) to distinguish them from infectious or communicable diseases.
Quite often, these are disorders most frequently found in older age groups but their incidence starts rising along each decade of adulthood. The deaths due to COVID-19, in the older age groups, are to a large extent explained by these coexisting health conditions. Those who do not suffer from any of these withstand the virus better. We have seen instances of the fit elderly walking out of hospitals unharmed by COVID-19, even in their 90s and past 100 years of age in Kerala and Italy.
Over the past 30 years, the world of global health has been debating whether infectious diseases have been overtaken by NCDs as the major global threat. The Millennium Development Goals of 2000 made no mention of NCDs despite the fact that the Global Burden of Disease Study in 1994 made it clear that they were the leading cause of death and disability globally, including in many developing countries. A very high economic burden was later attributed to these diseases globally, totalling $47 trillion between 2011 and 2030. Driven by the compelling evidence of both health and economic burdens, the Sustainable Development Goals (SDGs) of 2015 included the reduction of premature deaths from NCDs as a key target.
In high-income countries, the debate seemingly ended decades ago, in favour of NCDs. In the 1960s, a surgeon general of the US reportedly told the Congress, “It is time to close the book on infectious diseases, and declare the war on pestilence won.” As though to impart a quick lesson in humility, the HIV-AIDS pandemic erupted soon thereafter.
A number of zoonotic outbreaks and epidemics followed in different parts of the world—notable being swine flu, avian influenza, SARS and Ebola. The COVID-19 epidemic has come as another reminder that our hubris has played havoc with ecological balance and unleashed yet another zoonotic virus on us. Anti-microbial resistance too is a growing threat of the 21st century.
Claims and counter-claims of whether infectious diseases are the bigger health or economic threat are futile and counterproductive. They reinforce each other. Infections lead to inflammation, which can set off biological processes that result in blood vessel damage, diabetes, cancers and other NCDs. The NCDs, in turn, predispose affected individuals to infections and increase the risk of severe illness and death among the infected. Neither the human body nor human society has the option of choosing one over the other.
This has lessons for India. We have a very high prevalence of hypertension, cardiovascular disease, diabetes, chronic respiratory and kidney diseases, liver disorders and a variety of cancers. Many of these manifest at a younger age than in Western countries. The elderly, of course, manifest these more. We are already seeing the malign interaction of COVID-19 with these diseases in our hospital deaths. If the virus sweeps through the population, it will scythe many more lives.
We need to protect the elderly and others with these co-morbid chronic conditions from viral exposure. However, many people with NCDs are undetected in our country and even among those detected, there is a large proportion who are poorly treated or the disease inadequately controlled. That has been a weakness of our health system, which has started receiving attention only of late. Comprehensive primary health care, which provides a broad platform for addressing a wide variety of commonly encountered health problems, has only recently been mooted and is yet to mature to full strength.
Even as we gird our loins to combat COVID-19, we need to be cognisant of the reality that infectious and non-infectious diseases are part of the world we have created for ourselves as we interact with nature. We do this through a host of social, economic and environmental determinants that enable or erode our health at individual and population levels. We need a life course approach to public health, as vulnerability to infections increases at both ends of the age spectrum, but the portion in between too is important to build protection against NCDs. Even as we deal with a tiny particle of RNA, we need a holistic view of health and a cosmic view of the interconnected life on this planet.
Dr K Srinath Reddy
President, Public Health Foundation of India. Adjunct Professor of Epidemiology at the Harvard T H Chan School of Public Health. Views are personal.