Manas Dasgupta
NEW DELHI, Oct 4: Even as the daily new infection cases continued to dip and India on Monday recorded just about 20,000 cases, the experts continued to caution on the carelessness in the coming festival season and stressed on “responsible travel.”
The researchers have warned that a rise in population density driven by tourist arrivals or mass congregations due to social, religious or political events could lead to a surge in Covid infections worsening an anticipated third wave scenario in selected states.
The official data released on Monday morning said the daily cases of Coronavirus in the country remained below 30,000 for the 10th straight day with 20,799 fresh infections recorded in a single day, while the active cases declined to 2,64,458, the lowest in 200 days. With the fresh cases, India’s total tally of cases rose to 3,38,34,702, while the death toll climbed to 4,48,997 with 180 fresh fatalities
Illustrating a scenario where population density in India has a stronger effect on transmission than in the USA, the researchers said a holiday period could amplify a possible third wave peak by up to 103 per cent and cumulative incidence in that wave by 43 per cent. It could also hasten the timing of the epidemic peak by four weeks, compared to a scenario of easing restrictions in the absence of holiday travel, they said.
The opinion piece, based on mathematical models ‘Responsible travel to and within India during the Coid-19 pandemic’, by Balram Bhargava, Samiran Panda and Sandip Mandal from ICMR and Nimalan Arinaminpathy from Imperial College London, has been published in a journal on Monday.
In their study, the researchers illustrated some possible scenarios in a hypothetical state in India constructed to resemble Himachal Pradesh in the dynamics of its first and second waves, including the much lower seroprevalence of SARS-CoV-2 compared to the rest of the country.
“A sudden increase in population density due to incoming tourists or mass congregations due to social, political or religious reasons can worsen the third wave scenario,” the researchers said in the opinion piece.
Data from Himachal Pradesh suggests that in a typical holiday season, tourism can increase the population by 40 per cent.
A recent study in the USA suggests that an increase in one unit of log population density increased RO (the basic reproduction number/rate) by 0.16.
“Taking this into consideration, the third-wave peak can increase by up to 47 per cent during the holiday season and can occur two weeks earlier compared to a scenario of easing restrictions in the absence of holiday travel,” researchers said.
India’s second wave of Covid-19 was severe but showed varying impacts in different states. Smaller states with rarefied populations witnessed not only less intense spread than was apparent at the national level but also delayed attainment of the second peak, they observed.
Giving examples of popular tourist destinations such as Manali and Darjeeling, the researchers said observations indicate increasing opportunities for transmission in areas where population-level immunity has not yet accumulated to the same levels as elsewhere in the country.
“Against a backdrop of increasing anticipation of a third wave of Covid-19 in India, it is important to recognize the potential risks associated with such an escalation in travel,” they said. The researchers insisted on the travellers strictly using masks and maintain social distancing.
Beyond their protective effect, mandating these precautions will also serve as an important and continuing reminder of the risk of Covid-19, they said, adding conditions on travel like allowing tourists only with recent Covid-negative test report can also play a key role. Vaccine status can also play an important role in eligibility to travel, with some caveats, researchers said.
“Vaccine passports have limitations, arising from uncertainties about how the nature and strength of vaccine-induced immunity would change over time. Also, despite being the world’s largest producer of Covid-19 vaccines, India faces the challenge of having the world’s second-largest population to vaccinate.
“Nonetheless, as vaccination coverage scales, vaccine status can play an increasingly important role in eligibility to travel,” they said. Immunization planning may also benefit from prioritizing the local population in holiday destinations. Maintaining surveillance in at-risk settings, ensuring that virological testing is maintained even during apparent low infection activity would be important, the opinion piece stated.
Information on genomic surveillance in other nations and vigil at international airports would be valuable for early identification of unrecognized variants, it said. Observing that no national guideline exists on restrictions about domestic travel, the researchers said it might be helpful for holiday-destination states to get guidance on how they can best mitigate travel-related risks. “With the possibility of a severe third wave in India still looming, it remains critical to recognize and mitigate the risks involved.”
“A shared sense of responsibility, amongst visitors, residents and local authorities, will go a long way towards protecting the welfare of the country as a whole,” the researchers added.