Does the moderna covid-19 shot protect against brazil and south africa variants?

This is not yet fully clarified and is being studied. The m-RNA approach theoretically should offer protection, and so far, there seems to be value, but some people may not mount antibody response as fully as to original form. But seems, even if infected, the severity and lethality are far less than without.

With the Moderna COVID 19 vaccine, neutralizing antibodies dropped six-fold with South Africa (ZA) variant as compared to original strains. I have not found literature yet on effectiveness against Brazilian variant. However, ZA & Brazilian strains have many of the same changes to their spike protein but ZA has more of the changes. Thus, it may be that the ZA variant would be more of an issue.