Background: Our objectives were to describe the receipt of influenza and tetanus-diphtheria-acellular pertussis (Tdap) vaccines among postpartum women and their close contacts and the factors associated with cocooning.
Methods: A survey between February 2013 and April 2013 of 613 postpartum women from 9 obstetrics practices assessed vaccine receipt among respondents and close contacts, demographics and 5 domains of health beliefs (benefits, barriers, susceptibility, severity and social norms). Multivariable models assessed the association of these factors with Tdap or influenza "cocooning," defined as the mother plus at least 1 close contact of her newborn receiving the vaccine.
Results: The response rate was 45%; 61% of mothers reported that they and at least 1 close contact of their newborn had received influenza vaccine, and 67% reported this for Tdap. Infants whose mothers received influenza vaccine had a mean of 2.8 close contacts who also received influenza vaccine versus a mean of 0.9 contacts for infants whose mothers did not receive influenza vaccine (P < 0.0001). Infants whose mothers received Tdap vaccine had an average of 2.4 contacts who also received it versus 0.8 for infants whose mothers did not receive Tdap (P < 0.0001). Factors associated with influenza and Tdap cocooning included obstetrician recommendation, high perceived benefits, low perceived barriers and perceived susceptibility to disease. For Tdap, race/ethnicity was associated with cocooning (Hispanic/Latino, adjusted odds ratio 0.26, 95% confidence interval: 0.10-0.64 referent to White).
Conclusion: Maternal vaccination and obstetrician recommendation are associated with infant cocooning. Interventions to increase cocooning of infants should focus on encouraging strong provider recommendations, increasing maternal knowledge of disease risk and addressing identified barriers. Reasons for possible racial/ethnic differences should be further explored.