The Moderna coronavirus vaccine, set to arrive in the UK in the spring, is effective against all known variants of the virus that have been discovered.
This includes the new strain first detected in south east England that scientists say is more transmissible than the previous variant, and may be more deadly.
Moderna said laboratory tests found that vaccination with its jab produced neutralising antibodies against all key emerging variants, including the South African mutation.
The study showed no significant impact on antibodies against the UK variant relative to prior variants.
While there was a six-fold reduction in neutralising antibodies produced against the South African variant, the levels remained above those that are expected to be protective, Moderna said.
Stephane Bancel, chief executive officer of Moderna, said: "As we seek to defeat the Covid-19 virus, which has created a worldwide pandemic, we believe it is imperative to be proactive as the virus evolves.
"We are encouraged by these new data, which reinforce our confidence that the Moderna Covid-19 vaccine should be protective against these newly-detected variants."
The UK Government has purchased 17 million doses of the Moderna vaccine - enough to vaccinate 8.5 million people, but the first doses are not expected to arrive in the country until the spring.
The biotech company is also launching a clinical trial to test an additional booster dose of its vaccine (mRNA-1273) to study the ability to further increase antibodies against emerging strains beyond the existing primary vaccination series.
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The company is also advancing an emerging variant booster candidate (mRNA-1273.351) against the variant first identified in South Africa.
Mr Bancel added: "Out of an abundance of caution and leveraging the flexibility of our mRNA platform, we are advancing an emerging variant booster candidate against the variant first identified in the Republic of South Africa into the clinic to determine if it will be more effective to boost titers (antibodies) against this and potentially future variants."
