Covid Update: “Booster” Boost

On February 28th, the CDC recommended that adults over 65 get a second shot of the COVID vaccines released last fall. The viral sequence in the Moderna or Pfizer/BioNtek vaccines in the 2023-2024 “updated” versions matched the Omicron variant prevalent in early 2023, and they have enough overlap with current JN.1 variants to provide protection against serious disease resulting in hospitalization or death.


There are several compelling reasons to heed the CDC recommendations:

  • Immune responses to previous COVID vaccines have declined by 6 months post-vaccination in older individuals,
  • The new vaccine last fall was different enough from earlier COVID vaccines that it was really a first shot, not a booster amplifying prior immunity,
  • A second shot of the current vaccine really is a booster (if you got the first shot in the fall),
  • If you had a mild case of COVID this winter, if was probably due to the JN.1 variant, and the vaccine booster should prolong any immunity from that natural infection,
  • Almost all of the serious outcomes of COVID infection occurred in individuals over 65, so we are vulnerable, and we need to acknowledge that.
  • A new vaccine shot should be free to almost all individuals over 65.

The CDC made a point of calling new COVID vaccine formulations “updated” rather the “boosters.” That is fine if the new vaccine is different from the previous formulation, but if it is a second shot of the same vaccine, it is by definition a booster shot. Don’t ignore their advice because of semantics. Just get another shot and get ready for a new vaccine in the fall.