Distribution of Streptococcal Pharyngitis and Acute Rheumatic Fever, Auckland, New Zealand, 2010-2016

Abstract

Group A Streptococcus (GAS) pharyngitis is a key initiator of acute rheumatic fever (ARF). In New Zealand, ARF cases occur more frequently among persons of certain ethnic and socioeconomic groups. We compared GAS pharyngitis estimates (1,257,058 throat swab samples) with ARF incidence (792 hospitalizations) in Auckland during 2010-2016. Among children 5-14 years of age in primary healthcare clinics, GAS pharyngitis was detected in similar proportions across ethnic groups (≈19%). Relative risk for GAS pharyngitis was moderately elevated among children of Pacific Islander and Māori ethnicities compared with those of European/other ethnicities, but risk for ARF was highly elevated for children of Pacific Islander and Māori ethnicity compared with those of European/other ethnicity. That ethnic disparities are much higher among children with ARF than among those with GAS pharyngitis implies that ARF is driven by factors other than rate of GAS pharyngitis alone.