The vaccine showed a small drop in potency against the variant, compared with its effectiveness against the original virus, the company said. But the vaccine was more effective against the Delta variant than the Beta variant, first identified in South Africa — the pattern also seen with mRNA vaccines. Antibodies stimulated by the vaccine grow in strength over time, researchers also reported... “The coverage of the variants is going to be better than what people anticipated,” said Dr. Dan Barouch, a virologist at Beth Israel Deaconess Medical Center in Boston. “There was a lot of misinformation that was spreading, so we decided that we needed to get this into the public domain right away.”