When Pfizer announced plans in July to apply for approval for COVID-19 booster shots, U.S. officials said it was too early to know whether they were needed. Booster shots would only begin to be administered widely once the Food and Drug Administration formally approves the vaccines, which are being dispensed for now under an emergency use authorization. Last week, U.S. health officials recommended boosters for some people with weakened immune systems, such as cancer patients and transplant recipients. At the same time, the Delta variant is spreading aggressively through unvaccinated communities and causing an increasing number of “breakthrough infections” of fully inoculated people. Researchers are trying to understand to what extent the breakthrough infections are due to waning immunity, as opposed to the increased transmissibility of the Delta variant.

Source: Los Angeles Times August 17, 2021 20:03 UTC