COVID-19 patients in Iceland, according to a study published on Tuesday.In previous studies, antibody levels dropped sharply within a few months after COVID-19, raising questions about the duration of immunity that infection may provide.The new finding may have implications for reinfection risks and vaccine durability, said Kari Stefansson, chief executive of deCode Genetics, which conducted the study.To get a sense of how many people in Iceland had been infected with the new coronavirus and learn more about immune status after recovery, researchers measured antibody levels in more than 30,000 Icelanders.Based on the results, they estimate that about 1% of the population had been infected.