Third COVID wave unlikely to be as severe as second wave: ICMR study

A possible third wave of COVID-19 is unlikely to be as severe as the second wave given the extent of spread of coronavirus infections that has already taken place in the country, a study said.

The study titled "Plausibility of a third wave of COVID-19 in India: A mathematical modelling based analysis" underlines that the emergence of a third wave of coronavirus could be substantially mitigated by ramping up the vaccination.

“This study demonstrates plausible mechanisms by which a substantial third wave could occur, while also illustrating that it is unlikely for any such resurgence to be as large as the second wave,” the study published in the Indian Journal of Medical Research (IJMR) said.

The researchers cautioned that the projections were subject to uncertainties while asserting that scaling up vaccinations could substantially mitigate the emergence of a third wave of coronavirus.

"Preparedness planning for any potential future wave will benefit by drawing upon the projected numbers based on the present modelling exercise," the study said.

The study has been authored by Sandip Mandal, Balram Bhargava and Samiran Panda from the Indian Council of Medical Research (ICMR), and Nimalan Arinaminpathy from the Department of Infectious Disease Epidemiology, MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK.

The researchers examined four potential mechanisms for the emergence of a third wave of COVID-19 using a “deterministic, compartmental model” of SARS-CoV-2 transmission.

The four potential hypotheses are -- waning immunity restores previously exposed individuals to a susceptible state, emergence of a new viral variant that is capable of escaping immunity to previously circulating strains, emergence of a new viral variant that is more transmissible than the previously circulating strains and release of current lockdowns affording fresh opportunities for transmission.

The study said infection-induced immunity may decay over time, permitting re-infection of those previously exposed, even if the circulating virus remains unchanged.

Presenting a vaccine ramp-up scenario where 40 percent of the population has received two doses within three months of the second wave peak, and further that the effect of vaccination is (conservatively) to reduce severity of to infection by 60 percent, the study said it illustrates how vaccination could substantially reduce the overall burden during the possible third wave.