In the two-plus years that Sars Cov-2 vaccines have been available, their basic “recipe” has changed only once.

Instead, the virus already has five main variants, followed by many sub-variants of Omicron, each spreading faster than the last.

It takes months to modify a vaccine, and they can’t handle a virus that seems to be “reinventing itself every week,” Atlantic magazine notes in its analysis.

Antigenic “sin”

But the evolution of SARS-CoV-2 may not be the only reason immunity is stuck in the past. The human body seems to cling to the first version of the virus to which he was exposed, either through a vaccine or an infection — a condition that researchers call original antigenic sin, and which may leave us with little protection against current options.

In recent months, some experts have begun to fear that this “sin” could now undermine the effectiveness of updated vaccines. Recent evidence supports this hypothesis: previous exposure to a virus or primary vaccine appears to shape or even blunt the body’s response to updated vaccines. “I have no doubt about it,” says Jenna Gutmiller, an immunologist at the University. Colorado School of Medicine.

The immune system does not produce antibodies that target Omicron in the same quantity or quality as if it had received the updated vaccine directly.