The Delta variant of the coronavirus, which was first detected in India last October, is causing global concern with studies showing it is more contagious and resistant to vaccines than other strains of COVID-19. A British study published in the Lancet medical journal in early June found that antibody levels in people with two doses of the Pfizer/BioNTech shot were six times lower in the presence of the Delta variant than in the presence of the original COVID-19 strain on which the vaccine was based.