RecruitingPhase 4Biological interventionGenetic Variation in IgG in Alpha 1 Antitrypsin DeficiencyThe goal of this study is to learn whether patients who have a genetic mutation in the genes that cause alpha 1 antitrypsin deficiency also have genetic variation in nearby genes that can increase risk for reduced immune function and respiratory infections. To investigate this hypothesis, we will compare immune responses to the 20-valent pneumococcal conjugate vaccine (PCV20, Pfizer) between participants who have one abnormal copy of the SERPINA1 gene and either no COPD exacerbations, vs those with 2 or more COPD exacerbations in the past year.