2277. Whooping Cough: Epidemiological Changes After Tdap Maternal Immunization Strategy in a Pediatric Hospital

BACKGROUND: Whooping cough is a major cause of morbidity and mortality in infants younger than 1 year old. In 2012 Argentina introduced Tdap in pregnancy to prevent infant mortality. The aim was to describe the clinical and epidemiological profile of Bordetella pertussis (Bp) comparing pre and post Tdap maternal immunization periods. METHODS: All laboratory PCR confirmed Bp cases between December 2003 and December 2017 were included in “R. Gutierrez” Children’s Hospital. Statistical analysis was performed comparing clinical epidemiological features, Bp hospitalization rates (per 10,000 discharges) and lethality rates (%), between pre-vaccination (PreV) 2003–2011 and post-vaccination maternal immunization strategy (PostV) 2013–2017 periods, excluding intervention year (2012). RESULTS: From 1075 suspected cases, 350(32.6%) were Bp confirmed cases; median age 3 months (IQ = 2–7 months), 38% <3 months, 68% <6 months, 83% <12 months; 55% females; 18% had comorbidities; prematurity 10%, malnourishment 1%, and immunosuppression 1%; 81% required hospitalization, median length of stay was 6 days (IQ = 4–10 days), 17% in UCI. Confirmed cases showed a seasonal pattern predominantly from September through February (spring–summer). In comparison with PreV, PostVcases were older (3 vs. 9 months; P < 0.001), required less hospitalization (87% vs. 68%; P < 0.001), HR (22.3 vs. 10.9; P < 0.001) and LR (6.8% vs. 0%; P = 0.03) decreased and had a higher proportion of complete primary vaccination schedule (44% vs. 11%, P < 0.001). No difference found in gender (females 62% vs. 54%; P = 0.23), length of stay days (P = 0.51) or intensive care requirement (18% vs. 17%; P = 0.91). All fatal cases occurred in PreV. CONCLUSION: After maternal immunization strategy Bp confirmed cases were older, required less hospitalization and had a higher proportion of complete primary vaccination schedule. Hospitalization and lethality rates showed a significant decrease. There were no fatal cases in our center after this intervention. DISCLOSURES: All authors: No reported disclosures.