For more than a year now, the original COVID-19 vaccines have held up remarkably well — even miraculously so — against a Greek alphabet of new variants: Alpha, Beta, Gamma, Delta.

But now experts say something is changing. Since the start of 2022, the initial version of Omicron, known as BA.1, has been spinning off new sublineages — BA.2, BA.2.12.1, BA.4, BA.5 — at an alarming pace.

Earlier variants did this too. But it never really mattered, because their offshoots “had no functional consequence,” according to Eric Topol, founder of Scripps Research Translational Institute. “They did not increase transmissibility or pathogenicity.”

Today’s rapidly proliferating Omicron mutants are different, however. They all have