SANTIAGO (Reuters) - Chilean health officials on Thursday extended a lockdown across the capital Santiago to tame a second wave of infections even as the South American nation continues to plow ahead with the world’s fastest per capita vaccination campaign. Cases in Chile have been ticking up for weeks following the end of the southern hemisphere summer holiday, but topped a record on Saturday, bringing hospitals to the verge of collapse. Authorities announced a raft of new restrictions on Thursday, clamping down on travel inside the country and temporarily eliminating permits that allow those in quarantine to leave their homes to go grocery shopping, calling the more extreme measures “a last effort.” Large swathes of Santiago, a city of more than 6 million and the country’s economic engine, were already under lockdown, but officials said the remainder of the city would also be quarantined to slow the virus’s spread. The new restrictions come even as Chile, a comparatively small but wealthy Andean nation, is currently vaccinating faster per capita than any other, according to a Reuters tabulation of countries with populations of more than 1 million. Officials say cases spiked alongside the arrival of more contagious variants of the virus and a relaxation of sanitary measures during the successful vaccination program. Chile was the first in South America here to begin vaccinating its citizens, with an early shipment of the Pfizer vaccine on Dec. 24.