Evaluation of Pertussis Disease in Young Infants in India: A Hospital-Based Multicentric Observational Study

To evaluate the incidence of laboratory-confirmed pertussis (LCP) among infants hospitalized with acute respiratory infections (ARIs) and meeting the Centers for Disease Control and Prevention (CDC)-recommended clinical case definition. An investigator-initiated active surveillance for clinically suspected cases (CSCs) of pertussis screened infants aged ≤6 mo hospitalized with ARIs during January 2020-April 2022 at seven centers across India. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect Bordetella pertussis in nasopharyngeal swabs. Infants were classified as having ‘LCP’ or ‘probable pertussis’ (PP). Among 1102 screened infants, 400 participants met the CDC-2020 clinical case definition for pertussis. Of these, 34/400 (8.5