Childhood Immunization Perceptions and Practices among Members of on-Line Parenting Networks — San Diego, California, 2008

Background:
Lower rates of vaccination increase individual and community risk for vaccine-preventable diseases. A February 2008 measles outbreak in San Diego occurred among children intentionally unvaccinated against measles and spread to susceptible infants in the community.

Objectives:
To explore differences in perceptions toward vaccines and vaccine-preventable diseases between parents of fully vaccinated, selectively vaccinated (receipt of only certain vaccines), and completely non-vaccinated children; to examine household vaccine refusal and spacing (delayed vaccine receipt) trends; and to describe reasons for non-adherence to Advisory Committee on Immunization Practices (ACIP) recommendations.

Methods:
Major themes from key informant interviews and community focus groups on childhood immunization informed the development of a web-based survey instrument. The self-administered survey was implemented among members of two San Diego based on-line parenting networks. We compared responses from parents of fully vaccinated, selectively vaccinated, and non-vaccinated children.

Results:
Over half of the respondents (53.7%, n=125) reported a fully vaccinated youngest child. The remaining under-vaccinating respondents reported a selectively vaccinated (32.6%, n=76) or completely non-vaccinated (13.7%, n=32) youngest child. When independently compared to fully vaccinating respondents, a higher proportion of selectively vaccinating and non-vaccinating respondents believe that risks of vaccination are greater than risks of illness caused by some or all vaccine-preventable diseases (91.8% vs. 19.5%, p<0.0001; 100.0% vs. 19.5%, p<0.0001; respectively); natural immunity from getting some or all vaccine-preventable diseases is better than vaccine protection (90.0% vs. 23.1%, p<0.0001; 96.9% vs. 23.1%, p<0.0001; respectively); and the recommended immunization schedule is concerning (98.7% vs. 55.9%, p<0.0001; 100.0% vs. 55.9%, p<0.0001; respectively). Over half of the respondents (52.2%, n=23) from households with increasing vaccine refusal among subsequent children cited an older child's adverse vaccine reaction as the main reason for behavior change.

Conclusions:
Understanding parental perceptions regarding immunity against vaccine-preventable diseases and concerns about vaccines will help develop and target appropriate risk communication and educational messages.