Unless India sees four weeks of low and stable numbers of COVID-19 cases with only minor fluctuations, the disease cannot be considered to be entering the endemic stage, noted virologist Dr T Jacob John said.
He also said the endemic phase of COVID-19 is expected to last many months and it is " most unlikely" that another variant with higher transmissibility than Omicron and greater virulence than Delta will emerge.
The third wave of COVID-19 in India has been plateauing. The number of cases started declining after January 21, when 3,47,254 infections were reported. As of Tuesday, India's daily COVID-19 cases have remained below one lakh for nine consecutive days. John said the term endemic is meant to qualify a pattern.
"When case numbers in a community are plotted on graphs, the pattern of rise, peak and fall represent epidemic (or outbreak) and case numbers as a horizontal steady state are called endemic. When an epidemic pattern repeats, we call each a wave.
"So unless we see four weeks of low and stable numbers with only minor fluctuations, we cannot call the valley as endemic just as yet," John told PTI.
"Omicron wave is receding so fast that in a few more days we may reach the valley, but we will wait for four weeks to be sure of endemic prevalence," he said.
Asked what can be expected in the coming months, the former director of the Indian Council for Medical Research's Centre of Advanced Research in Virology said it cannot be predicted, but only speculated.
"My intelligent guess: we will slip into an endemic phase for many months without any more waves with Alpha, Beta, Gamma, Delta or Omicron. It will be most unlikely that yet another variant that will spread faster than Omicron and more efficient in immune evasion that Delta or Omicron will emerge," John said.
"However, just as Omicron surprised us, another weird variant could surprise us yet again," he warned.
He also said that during the endemic phase, some will be infected, sick, hospitalised and even die.
John cautioned that without high vaccination coverage, small waves may recur perhaps once a year or once in a few years, modulated by vaccination coverage in all age groups.
"We have vaccines. For all current vaccines, two doses plus a booster are the minimum schedule. Additional boosters will be decided on future information," he added. -- PTI