def get_all_individuals_to_be_vaccinated_by_area(
    vaccinated_compartments, non_vaccination_state, virus_states, area
):
    """Get sum of all names of species that have to be vaccinated.

    Parameters
    ----------
    vaccinated_compartments : list of strings
        List of compartments from which individuals are vaccinated.

    non_vaccination_state : str
        Name of state indicates non-vaccinated individuals.

    virus_states : list of strings
        List containing the names of the virus types.

    area : str
        Name of the area.

    Returns
    -------
    vaccinated_individuals : str
        Sum of all names of species that have to be vaccinated.
    """

    vaccinated_individuals = ""
    for index_compartments in vaccinated_compartments:
        for index_virus in virus_states:
            for index_areas in [area]:
                if index_compartments != "susceptible":
                    state = f"{index_compartments}_{index_areas}_{non_vaccination_state}_{index_virus}"
                    vaccinated_individuals = vaccinated_individuals + "+" + state

    for index_areas in [area]:
        state = f"susceptible_{index_areas}_{non_vaccination_state}"
        vaccinated_individuals = vaccinated_individuals + "+" + state

    return vaccinated_individuals