The Delta variant of COVID-19 can transmit easily from vaccinated people to members of their households, a year-long British study found. Scientists at the Imperial College London published a study in the Lancet Infectious Diseases medical journal on Thursday that discovered that the efficacy of the COVID-19 vaccine wanes earlier than previously believed. The study involved 621 people in the U.K. and found that their peak viral load was similar regardless of vaccination status. The study found that of 205 household contacts of people who had the Delta infection, 38% of household contacts who were unvaccinated tested positive for COVID-19, and 25% of vaccinated contacts tested positive for the Delta variant of coronavirus. “By carrying out repeated and frequent sampling from contacts of COVID-19 cases, we found that …