Israeli officials are warning that the Pfizer vaccine is “significantly less” effective against the Delta variant of the coronavirus, the strain first seen in India that now accounts for 31 percent of cases in the US. “We do not know exactly to what degree the vaccine helps, but it is significantly less,” said Israeli Prime Minister Naftali Bennett. The shot is still keeping people from getting seriously ill in Israel, where over 60 percent of the population has received a jab. Just 1.6 percent have become critically ill, compared with 4 percent in the pre-vax wave of cases. Concerns are also rising about the effectiveness of vaccines against the Beta variant, first identified in South Africa. The UK will require all travelers from France — including the fully vaccinated — to isolate for 10 days when they return because the Beta variant is spreading there, though mostly in the Indian Ocean territories of Reunion and Mayotte.