Results
Study Population
The response rate was 45% (274 of 613). Differences between respondents and nonrespondents were assessed using limited data available from the previous paper survey. Available data showed that survey respondents were slightly older than nonrespondents (30.7 years vs. 29.4 years, P = 0.005), were more likely to report having a primary care provider besides their OB/GYN (57% vs. 46%, P = 0.006) and were more likely to have reported receiving influenza immunization in the prior season (52% vs. 38%, P < 0.001) and Tdap vaccination since 2005 (31% vs. 15%, P < 0.001). The characteristics of respondents are shown in Table (Supplemental Digital Content 1, http://links.lww.com/INF/C233). The study population was predominantly White (82%), highly educated (67% college graduates or with advanced degree) and privately insured (81%). The mean number of close contacts per newborn was 5.1 (standard deviation, 3.0).
Outcomes
Sixty-seven percent of respondents reported that they had received both influenza and Tdap vaccines during the specified time frames. Seventy-four percent of mothers reported having received influenza vaccine during the current influenza season. Of these, 2% reported receipt before pregnancy, 46% while pregnant and 52% after delivery. Sites of receipt of influenza vaccine included their OB/GYN provider's office (40%), another medical provider's office (21%), hospital after delivery (10%), retail pharmacy/grocery (8%), public health department (2%) or other (19%, most responses listed as "work"). Eighty-six percent of mothers reported that they had received a Tdap vaccine since 2005. Of these, 35% reported receipt before the recent pregnancy, 14% during the recent pregnancy and 52% sometime after delivery. Sites of receipt of Tdap vaccine included a hospital after delivery (46%), another medical provider's office (25%), their OB/GYN provider's office (16%), a public health department (4%), a retail pharmacy/grocery (1%) and other (8%).
Over one-half of respondents strongly agreed that they worried that either they or someone else would infect their baby with influenza or pertussis (Table 1). Over three-fourth of respondents strongly agreed that it would be really bad if their baby got influenza or pertussis. More respondents strongly agreed that Tdap vaccine is a good way to protect the health of newborn babies (73%) than those who strongly agreed with the same statement about influenza vaccine (59%, P < 0.0001). The most commonly reported barrier was regarding the safety of influenza vaccine, with 13% strongly agreeing and 33% somewhat agreeing that they worry about its safety. A similar but slightly lower proportion of women reported concerns about the safety of Tdap vaccine and vaccines in general. Three percent of respondents strongly agreed and 19% somewhat agreed that it is dangerous for pregnant women to get vaccines. More than half of the respondents strongly agreed with all of the social norms statements.
Seventy-one percent of respondents reported having received a recommendation for influenza vaccine from their obstetrician, and 64% reported the same about Tdap vaccine. Fifty-two percent and 51% reported receiving a recommendation from their obstetrician that close contacts of their newborn infant receive influenza and Tdap vaccine, respectively. Smaller percentages reported having received similar recommendations from other staff members in the OB/GYN office (Fig. 1).
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Figure 1.
Reported receipt of recommendations for influenza and Tdap vaccination from providers in obstetrics and gynecology offices. P < 0.001 for all comparisons between obstetrician and nurse midwife/NP/PA, χ. NP indicates nurse practitioner; PA, physician assistant.
Sixty-one percent 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 reported receipt of influenza vaccine for themselves had a mean of 2.8 close contacts (median = 3) who also received influenza vaccine when compared with 0.9 (median = 0) contacts for mothers who did not receive influenza vaccine (P < 0.0001). The difference was also striking for Tdap, with infants whose mothers reported Tdap receipt having on an average of 2.4 contacts (median = 2) who also received it versus 0.8 (median = 0) for infants whose mothers did not report Tdap receipt (P < 0.0001). Twenty-five percent reported that they and all their close contacts had received influenza vaccine. The same was true for Tdap vaccine (25%), whereas only 14% reported that they and all their close contacts had received both influenza and Tdap vaccines.
In bivariate analyses for each vaccine (Table 2), mothers who reported cocooning were slightly older and more likely to be White than Hispanic or other race. For influenza vaccine cocooning, specifically, all HBM domains except perceived severity were associated. Specifically, the likelihood of cocooning increased with increased perceived benefits of vaccination, perceived susceptibility to illness and normative influences, and the likelihood of cocooning decreased with higher perceived barriers. Obstetrician recommendation for both mothers and close contacts to receive the vaccine was also associated with cocooning. Three domains (benefits, barriers and susceptibility) and obstetrician recommendation for the mothers maintained this association after adjustment in multivariable models.
In addition, mothers who reported cocooning against pertussis were more highly educated and less likely to report having Medicaid insurance. All 5 HBM domains were associated with cocooning for Tdap vaccine in bivariate analyses. Of these, barriers and susceptibility maintained this association with Tdap cocooning after adjustment in multivariable models. Obstetrician recommendation for the mother to receive the Tdap vaccine was also associated with cocooning. Hispanic race also maintained the association after adjustment, with a lower likelihood of cocooning when compared with White race.