Joan Valls/Urbanandsport /NurPhoto via Getty Images A major new study in one of Europe's worst affected countries for the coronavirus finds no evidence of widespread immunity to the virus developing. Just 5% of Spaniards were detected to have antibodies to the virus. Fourteen percent of people who previously tested positive for antibodies tested negative just weeks later. The study suggests people who experience mild symptoms do not have long-lasting protection. "Immunity can be incomplete, it can be transitory, it can last for just a short time and then disappear," Raquel Yotti, the director of Spain's Carlos III Health Institute, said. Another scientist involved said: "In light of these findings, any proposed approach to achieve herd immunity through natural infection is not only highly unethical, but also unachievable." Visit Business Insider's homepage for more stories.