BERLIN : Variant forms of the novel coronavirus which were first reported in South Africa and Brazil are less efficiently inhibited by antibodies from recovered patients and vaccinated individuals, a new study confirms.According to the research, published in the journal Cell, recovery from COVID-19 as well as vaccination may offer only incomplete protection against these mutant virus forms."This is worrisome because the rapid spread of variants that might not be efficiently inhibited by antibodies could undermine our current vaccination strategy," said Stefan Pohlmann, a co-author of the study from the German Primate Center in Gottingen.These virus variants have mutations in the spike protein -- the structure on the surface of the virus.