If COVID-19 booster shots become an annual precaution, the same way we get a flu shot every year, the next one may be formulated differently.

Moderna and Pfizer working on a bivalent vaccine that offers protection from the omicron variant.

Moderna tells NBC News it believes omicron or delta could be the dominant variants this fall.

The company plans to combine its original formula with an omicron-specific vaccine.

Moderna has already begun human trials and hopes to test out the new vaccine in 375 participants in the U.S.

It is unclear how quickly the new vaccine from Moderna or Pfizer could receive FDA approval after trials.