New Delhi: Delhi Health Minister Satyendar Jain’s statement Sunday that the novel coronavirus disease is nearing its “endemic phase” in the national capital has sparked a debate, with experts saying it’s “too early to make that assessment”.
“Coronavirus is nearing an endemic phase in Delhi. Experts say some cases continue to occur in the endemic phase. Delhi witnessed a swine flu outbreak around 10 years ago, but still some cases are reported every year. Coronavirus is not going to end completely … we will have to learn to live with it,” Jain said.
Endemicity means a steady flow of cases across the year and a region — occasionally with a slight spurt in some seasons. A case in point is the seasonal flu that occurs all the year round, but shows a slight increase as seasons change.
A 2015 paper in the Indian Journal of Endocrinology and Metabolism on whether diabetes is endemic or an epidemic in India referred to an old definition of cholera to explain the concept of endemicity.
“One old (dating to 1948) clinically-based definition proposed for cholera is still relevant. It states: An endemic area is one in which over a number of years, there is practically continuous presence of clinical cholera with annual seasonal exacerbation of incidence,” the paper stated.
“The Dictionary of Epidemiology defines an endemic disease as the constant presence of a disease or infectious agent within a given geographic area or population group; may also refer to the usual prevalence of a given disease within such an area or group,” it added.
Health experts said the endemicity of Covid-19 is difficult to establish conclusively as a flurry of new strains of the virus has cropped up. They also said that with the use of two Covid-19 vaccines, there is little chance of the disease becoming endemic.
‘Too early to say’
There is no defined inflection point in the life of a pandemic when it can be said that a disease has become endemic.
“In my view, it is still too early to make that assessment about Delhi,” said Dr K.S. Reddy, president Public Health Foundation of India, who also serves as an adjunct professor of epidemiology at Harvard School of Public Health.
“If there are spikes or waves then usually it is not endemic, there could be some seasonal fluctuations. When there is a steady rate of mild numbers, that is when the disease can be said to be settling down. But then with more people, travelling numbers can go up very sharply at any time. One way of looking at it is if serious infections are few…,” he explained.
Delhi has been reporting reduced occupancy of Covid patients across hospitals for some time now. The latest Delhi health bulletin showed that of the 5,709 designated Covid-19 hospital beds, only 539 are occupied.
However, with several strains of the virus in circulation and travel-related cases likely to crop up at any time, endemicity is difficult to establish conclusively.
“No country in the world has so far said that the disease has become endemic there. Part of the reason is the newer strains that are circulating. Take the UK for example, there was a wave and then a new strain arrived and yet another wave started. Nothing in the Delhi data that I am currently looking at gives the impression that the disease is endemic,” a senior official of the National Centre for Disease Control (NCDC) told ThePrint.
He added that with two vaccines already being in use, chances of the disease becoming endemic seem to be relatively lower.
Predictions of endemicity
That Covid-19 becoming endemic at some point was accepted not just in the containment plan for large outbreaks that the central government drew up in February 2020 — last revised in May — but also in several international journals.
Last month, The BMJ wrote “The SARS-CoV-2 coronavirus will not be eradicated, but will become endemic, continuing to circulate in pockets of the global population for years to come and causing outbreaks in regions where it had been eliminated, scientists working in the field believe.”
“But the impact of the virus on the world in terms of deaths, illness, and the need for social isolation will lessen, they say, as more of the population acquires some immunity to it through exposure to the virus or from vaccination.”
However, two things could delay the likelihood of Covid-19 becoming endemic — one is travel that could mean the influx of new strains, and the second is vaccination.
Christopher Dye, an epidemiologist at the University of Oxford, UK, told The Nature last month, “I guess Covid-19 will be eliminated from some countries, but with a continuing (and may be seasonal) risk of reintroduction from places where vaccine coverage and public-health measures have not been good enough.”
How strategy changes for an endemic disease
One of the primary shifts in disease containment strategy that takes place when a disease becomes endemic is that resources are then diverted — from trying to contain the disease to trying to minimise damage.
“In such a scenario, the idea should be to resume life while protecting the most vulnerable, the immune-compromised, elderly or those with comorbidities. They have to reduce overall exposure till immunisation is done. It is also important to monitor mutants,” said Dr Reddy.
Mitigation stage means that the sole aim is to reduce mortality and morbidity, i.e., prevent patients from getting more serious.
“It is what we do for seasonal flu. We only test those that are in risk of serious illness or those that land up in hospitals,” said the NCDC official quoted above.
(Edited by Debalina Dey)