Omicron booster shots may be here by September

New booster shots specific to the Omicron variant could be ready soon after Labor Day, now that Moderna and Pfizer asked the Food and Drug Administration this week to authorize the vaccines.  Unlike the initial boosters, the updated shots are “bivalent,” my colleagues Ryan Cross and Camille Caldera reported. That means they include the original formulation, plus an updated version based on the genetic code of the BA.4 and BA.5 subvariants. Dr. Richard Ellison III, a hospital epidemiologist at UMass Medical Center, expects that the new boosters will provide good protection against hospitalization and death. But how the shots fend off mild illness and infection will depend on how much the virus continues to change. Pfizer hopes the shots will be approved for people 12 and older. Moderna is targeting all adults. Here are all your questions, answered.  Other top stories  We've come a long way from 2020. If you’re looking to reminisce, Globe correspondent Katie Mogg compiled memories of hoarding toilet paper and baking sourdough.  Vaccines have helped Massachusetts avoid “excess mortality,” or deaths exceeding the expected number at any given time of year, during two surges in the pandemic, a new study found.  Health leaders are urging cities to enact more comprehensive COVID policies before an expected rise in cases this fall and winter.  First lady Jill Biden tested positive for COVID Wednesday again in an apparent “rebound” case, after testing negative a few days earlier.