Medical practitioners in Kolkata have raised alarm over the increased number of lower respiratory tract illness among Covid-positive patients, especially in the case of patients who are ‘unresponsive’ to vaccines. The hospital authorities in the city have pointed out that a section of elderly patients with comorbidities may not have developed adequate antibodies, which could be the cause for the concerning numbers of respiratory infections. Medical experts have also pointed out that the residual delta cases seem to be causing an even more severe hit, particularly in elderly patients with comorbidities. Hospital authorities also said that they have ensured oxygen support and non-invasive ventilation support for all critical patients and expressed hopes for condition improvement.