Since most of the current COVID-19 vaccines are designed based on the original SARS-CoV-2 strain, the fast evolution of the Omicron leading to the emergence of highly transmissible strains like BA.4 and BA.5 is making the current vaccines obsolete.
These differences are leading to a poor match between the current Omicron strains and the original Wuhan strain enough to prompt the FDA to suggest that the vaccine developers should update their jabs to include a portion of the Omicron variant, the version of the coronavirus that currently dominates the globe.
Although this is not a new discussion within the scientific community about the ultimate need for the vaccine upgrade, the rapid emergence of highly transmissible strains like BA.4 and BA.5, which are known to erode the immunity obtained from vaccination and infection with previous strains, including earlier versions of Omicron is making it more essential than ever.
Most likely the CDC will not recommend the updated vaccine for everyone but would be selected for boosters in the fall. Since there is very little understanding of how SARS-CoV-2 could evolve in the future, and the virus has always been ahead of our predictions, the task of vaccine upgrade is daunting.