Specific Aim 7: To determine whether macrolide resistance in Streptococcus pneumoniae, Hameophilus influenzae, and Staphylococcus aureus is more prevalent in communities treated with biannual mass azithromycin compared to communities treated with annual mass azithromycin, and to determine whether targeted azithromycin treatments result in less macrolide resistance compared to mass azithromycin distributions.