Pfizer partner BioNTech is exploring a variant-specific vaccine strategy

German company BioNTech told investors Monday there is “no evidence” it must change the vaccine it developed with Pfizer to cope with coronavirus variants that are pinging around the globe, but it is exploring contingency plans with U.S. regulators anyway.

The Mainz-based pioneer in messenger-RNA technology said it is evaluating whether a booster dose five to seven months after completion of the initial two-dose course impacts the durability of protection against variants that arise as the virus evolves.

The study, which began in March, includes a group that is receiving a vaccine specially encoded for the B.1.351 variant that is prevalent in South Africa and appears to diminish, though not overcome, the efficacy of the existing vaccine.

“To date, there is no evidence that an adaptation of BioNTech’s current COVID-19 vaccine against key identified emerging variants is necessary,” the company said in detailing first-quarter results. “Despite this, BioNTech has developed a comprehensive strategy to address these variants should the need arise in the future.”

All told, BioNTech and Pfizer have shipped about 450 million doses of the vaccine to 91 countries and territories around the world. They have signed contracts to deliver 1.8 billion doses during 2021 as the world races to wrangle down the virus.

The Pfizer-BioNTech vaccine was the first one approved for emergency use in the U.S. and remains a predominant option.