Prolonged or intermittent social distancing may be necessary even until 2022 to prevent future Covid-19 seasonal outbreaks, a new study has said.Researchers from Harvard University, led by Stephen Kissler, used estimates of seasonality, immunity, and cross-immunity for two betacoronaviruses from time series data from the United States, to inform a model of Covid-19 transmission, Xinhua news agency reported.Recurrent wintertime outbreaks of Covid-19 "will probably occur after the initial, most severe pandemic wave," researchers wrote on in the study 'Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period', published in the online journal Science.The researchers added that without a vaccine or other interventions, "prolonged or intermittent social distancing may be necessary into 2022."Noting that "a key metric for the success of social distancing is whether critical care capacities are exceeded," the study said that "additional interventions, including ...