The companies say the vaccine prevented the return and spread of the cancer in high-risk melanoma patients. Breaking down the science behind Moderna and Merck's landmark mRNA cancer vaccine for melanoma. Key points and original sources are listed below.

• The companies say the vaccine prevented the return and spread of the cancer in high-risk melanoma patients.S1

• Breaking down the science behind Moderna and Merck's landmark mRNA cancer vaccine for melanoma.S2