Implementation of Cocooning against Pertussis in a High-Risk Population

Background: Pertussis-related complications and deaths occur predominantly in infants too young to have received their primary immunization series.  In 2006, the ACIP recommended tetanus, diphtheria, acellular pertussis (Tdap) booster immunization of infant caregivers (“cocooning”), the source of approximately 75% of infant pertussis cases. 

Objectives: To implement cocooning in a predominantly Hispanic, medically underserved, uninsured population at a Houston hospital.  Phase I (January 2008-November 2009) provided postpartum Tdap, Phase II (June-November 2009) immunized infant caregivers on-site before infant hospital discharge.

Methods: Pertussis education was provided to healthcare personnel.  A standing order for postpartum Tdap immunization was initiated.  Bilingual educational materials regarding Tdap vaccine were provided for all mothers.  Mothers were interviewed to ascertain the number of additional infant contacts eligible to receive Tdap.  Consenting eligible caregivers received Tdap prior to infant discharge from hospital. The demographics of vaccinees and reasons for Tdap refusal were recorded.

Results: From January 7, 2008 to November 30, 2009, 7,544 of 10,394 (73%) postpartum women received Tdap vaccine; 6,957 (92.2%) were Hispanic; others were black (5%), white (1.1%), Asian (1.2%) and other (0.6%).  Among a subset of 1174 women, 96.2% who believed themselves Tdap eligible were immunized; vaccine refusal was 3-fold more common among black women.   From June through November 2009, 1,510 other infant caregivers received Tdap.  The median number of Tdap eligible caregivers per infant was 3 (1-11); a median of 2 (1-10) were immunized.  792 (58%) of fathers were immunized.  No significant adverse events were reported.  Barriers identified included the need for extended immunization hours, visiting restrictions due to pandemic H1N1 influenza and inaccurate recall of vaccination history.

Conclusions: While practical and logistical barriers exist, Tdap cocooning was well accepted and successfully implemented in a high-risk population using standing orders and providing immunizations on-site.