BOSTON — A heavily mutated COVID-19 strain that laid dormant for four years has been detected in Massachusetts wastewater, raising concerns that current vaccines may not protect against it.

The variant, known as BA.3.2 and nicknamed "Cicada" for its long hibernation underground, carries between 70 and 75 mutations — far more than typical circulating strains. It has now been confirmed in 25 U.S. states and 23 countries worldwide.

The CDC has flagged the strain for monitoring, noting that laboratory studies have shown it "efficiently evades antibodies, likely because of spike protein mutations."

"It has a lot of mutations that may cause it to look different to your immune system," said Andrew Pekosz, PhD, a virologist at the Johns Hopkins Bloomberg School of Public Health.

BA.3.2 is a descendant of the Omicron variant that first emerged in late 2021 but circulated at extremely low levels for years — earning it the "Cicada" nickname for its prolonged dormancy before resurfacing. It was first detected in South Africa in 2024 and has since spread globally.

What sets it apart from other circulating variants is the sheer number of mutations — 70 to 75 — which may allow it to evade immunity from both prior infection and vaccination.

Health officials say previously administered vaccines still provide some protection against currently circulating variants, but the Cicada strain's ability to dodge antibodies is raising red flags.

Symptoms are believed to be similar to other current COVID variants, including cough, fever, fatigue, and body aches.

The CDC says it is actively monitoring the spread of BA.3.2 to assess "the potential for this new SARS-CoV-2 lineage to evade immunity from a previous infection or vaccination."