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During the H1N1 pandemic in 2009-10, the vaccination behavior of parents played a critical role in preventing and containing the spread of the disease and the subsequent health outcomes among children. Several studies have examined the relationship between parents' health communication behaviors and vaccinations for children in general. Little is known, however, about the link between parents' health communication behaviors and the vaccination of their children against the H1N1 virus, and their level of vaccine-related knowledge. We drew on a national survey among parents with at least one child less than 18 years of age (n=639) to investigate Parents' H1N1-related health communication behaviors including sources of information, media exposure, information-seeking behaviors, H1N1-related knowledge, and neighborhood social capital, as well as the H1N1 vaccination rates of their children. Findings showed that there is a significant association between the degree at which parents obtained H1N1 vaccination for their children and health communication variables: watching the national television news and actively seeking H1N1 information. And this association was moderated by the extent of the parents' H1N1-related knowledge. In addition, the parents' degree of neighborhood social capital mediated the association between H1N1 knowledge of the parents and H1N1 vaccination acceptance for their children. We found, compared to those with a low-level of neighborhood social capital, parents who have a high-level of neighborhood social capital are more likely to vaccinate their children. These findings suggest that it is necessary to design a strategic health communication campaign segmented by parent health communication behaviors.

Despite being at highest risk for 2009 H1N1 virus morbidity and mortality, many children were not immunized with the vaccine. Identification of factors that put certain children at higher risk for under-immunization could reveal populations who may need to be specifically targeted for vaccination interventions in future pandemics. Little is known about the prevalence of, or factors associated with, 2009 H1N1 vaccine coverage in low-income, urban pediatric populations. This study evaluated 2009 H1N1 vaccination coverage in 19,643 children aged 6months to 18years receiving care at one of five community clinics associated with an academic medical center in a low-income community. Any (≥1 dose) and full coverage (1 dose for children ≥10years old, 2 doses for those10years) was determined as of December 1, 2009 and the end of vaccination period (June 30, 2010). Multivariable analyses were used to assess the impact of race/ethnicity, age, insurance, gender, and language on vaccine coverage and timeliness. By December 1, only 16.6% of children had received one dose, and 5.3% had full coverage. By the end of the vaccination period, 36.2% had received at least one H1N1 dose and 23.6% had full coverage. On multivariable analysis, older age, minority race/ethnicity, and private insurance were negatively associated with vaccination by December 1 and end of vaccination period, even after accounting for attendance at a clinic visit. In future pandemics, when timely receipt of a new vaccine in large populations may be imperative, general vaccination programs as well as special targeted education and vaccine reminders for these at risk groups may be warranted.

Live attenuated cold-adapted influenza vaccines (CAIVs) have been developed over the past two decades by taking advantage of the segmented RNA genome of influenza and creating attenuated reassortants containing contemporary hemagglutinin (HA) and neuraminidase (NA) genes. These vaccines have been shown to be easily administered, safe and immunogenic in adults and children. Recent trials of a trivalent live attenuated CAIV (CAIV-T, tradename FluMist, Aviron, Mt. View, CA) in children have demonstrated greater than 85% efficacy against culture positive H3N2 and B influenza illness and complications, such as otitis media. CAIV-T also prevented shedding of H1N1 virus in 83% of vaccinated subjects after a monovalent CAIV challenge. Nasal IgA and serum HA inhibition (HAI) antibody produced by these vaccines have been associated with protection against infection, but protection may exist even in the absence of identifiable antibody response. Work to date documenting phenotypic and genetic stability, low likelihood of reactogenicity, infrequent transmissibility and attenuating properties of reassortants heralds promise for the broad use of this vaccine. Targeting children to receive this vaccine may now prove practical and may serve to reduce overall influenza morbidity, given the significant contribution of the pediatric age group of children to influenza illness burden and community spread. Studies of vaccine use in community settings will aid in determining the public health future of this approach.

Sequence analysis of the influenza haemagglutinin, HA, (H1 and H3) suggests that many antigenic variants that are identified but which do not become predominant differ from contemporary epidemic strains in one or two amino acids, in the region 188–193. This information may assist in the optimum selection of vaccine strains when multiple variants are co-circulating. Genome analysis of H1N1 virus, from 1977 to 1983 (but not of H3N2 virus thus far) has identified two instances when large changes in total genome sequence was associated with major epidemic activity. The early detection of such gross genetic changes may provide a further indicator that can be used to forecast the likelihood of more widespread activity than normal.