C++ Using enum in a Class to specify value options for user input : I'm new to the implementation of enum, but have an idea on how it's supposed to be used.

I have the bellow Allergy program to record information about an allergy provided by user input. I want to add another option for the user to select the "severity" of the allergy.

I want to create an enum to hold the values the user should choose from. Here is what I have so far, but I'm just ignorant when it comes to enum and just how exactly it should be implemented. Thanks in advance for any help!!

Allergy.hpp:

    #ifndef Allergy_hpp
    #define Allergy_hpp
    
    #include <iostream>
    #include <string>
    #include <list>
    using namespace std;
    
    
    class Allergy {
    public:
        enum severity {mild, moderate, severe};
        
        Allergy();
        Allergy(string, string, list <string>);
        ~Allergy();
        
        //getters
        string getCategory() const;
        string getName() const;
        list <string> getSymptom() const;
        
        
    private:
        
        string newCategory;
        string newName;
        list <string> newSymptom;
        
        
        
    };
    
    #endif /* Allergy_hpp */

Allergy.cpp:

    include "Allergy.hpp"
    
    Allergy::Allergy(string name, string category, list <string> symptom){
        newName = name;
        newCategory = category;
        newSymptom = symptom;
    }
    
    Allergy::~Allergy(){
        
    }
    
    //getters
    string Allergy::getName() const{
        return newName;
    }
    
    string Allergy::getCategory() const{
        return newCategory;
    }
    
    
    list <string> Allergy::getSymptom() const{
        return newSymptom;
    }

main.cpp:

    #include <iostream>
    #include <string>
    #include "Allergy.hpp"
    
    using namespace std;
    
    
    int main() {
        string name;
        string category;
        int numSymptoms;
        string symptHold;
        list <string> symptom;
        
        cout << "Enter allergy name: ";
        getline(cin, name);
        cout << "Enter allergy category: ";
        getline(cin, category);
        cout << "Enter number of allergy symptoms: ";
        cin >> numSymptoms;
        
        for(int i = 0; i < numSymptoms; i++){
            cout << "Enter symptom # " << i+1 << ": ";
            cin >> symptHold;
            symptom.push_back(symptHold);
        }
        
        Allergy Allergy_1(name, category, symptom);
        cout << endl << "Allergy Name: " << Allergy_1.getName() << endl <<
        "Allergy Category: " << Allergy_1.getCategory() <<  endl <<
        "Allergy Symptoms: ";
        
        for(auto& s : Allergy_1.getSymptom()){
            cout << s << ", ";
        }
        
        cout << endl;
        return 0;
    }