Newly formulated COVID-19 vaccines are necessary because the performance of the current slate is slipping over time, U.S. officials said this week.
“There appears to be an inverse relationship between the time since vaccination and vaccine effectiveness, such that bivalent COVID-19 vaccine effectiveness against Omicron sublineages appears to wane over time,” officials with the Food and Drug Administration (FDA) said.
The vaccines were already updated in late 2022 to target Omicron subvariants like BA.5, with the hope they would perform better than the old vaccines.
But the shots have been providing subpar protection against infection and short-lived shielding against hospitalization, according to data from the United States and elsewhere. That prompted a partial rollback in the availability of the shots….