Explanation:

- Correct Answer:

  Option 1 - It is claimed that the medicine will "shelter" you against the coronavirus. Shelter implies providing protection.

- Option 2: "Immune" is not grammatically adaptable to fit directly into the sentence with the term “against.”

- Option 3: "Reinforce" means to strengthen or support, but when used in context with a disease or virus, it's typically not paired with "against."

- Option 4: "Fortify" generally means to strengthen or make more secure, but it's not typically used with "against" in the context of immunity or protection from diseases.