Nikki Turner

Understanding and predicting parental decisions about early childhood immunizations.

This research investigated the factors that influence decisions about immunizations. Women in the third trimester of pregnancy (N=195) rated their likelihood of immunizing their child; stated their reasons for and against immunizing; and rated their perceptions of the benefits and risks of immunization, feelings of responsibility, and anticipated regret if harm occurred. Immunization status was determined at follow-up. Stepwise regression analyses demonstrated that immunization decisions are strongly influenced by omission bias factors such as anticipated responsibility and regret variance (which explained more than 50% of variance). It is suggested that parents may benefit from antenatal decision aids that address omission bias and encourage them to assess benefits and risks of immunizations on the basis of scientific evidence.

Evaluation of a decision-making aid for parents regarding childhood immunizations

This intervention study evaluates a decision-making aid for parents considering childhood immunizations. Participants (women in 3rd trimester of pregnancy, n = 100) rated likelihood of immunizing their child, anxiety, and perceptions of risk of the diseases and immunizations. Individuals were allocated to intervention group (received a decision aid) or control group (received standard care). Ratings were then repeated, and further ratings were obtained when the infant was 10 weeks old. The intervention compared with the comparison condition was associated with significant increase in likelihood of immunizing the infant on time, decreased perceptions of risks of immunizations, increased perceptions of risk of the diseases, reduced anxiety, and increased satisfaction. This intervention may form a useful basis for decision aids in health care settings.

Recruitment of practices in primary care research: the long and the short of it

OBJECTIVE To determine factors that facilitated or hindered recruitment of general practices into a large New Zealand primary care project that aimed to determine general practice characteristics of immunization coverage. METHODS The project had a multi-level recruitment strategy requiring recruitment of randomly selected practices before randomly selecting GPs, practice nurses and caregivers of children enrolled at those practices. Detailed quantitative and qualitative recruitment data were recorded on an access database. Post-recruitment, recruiters underwent semi-structured interviews. Analysis was mixed method, with triangulation of descriptive statistics of the number of calls and time course to recruitment and general inductive thematic analysis of qualitative data. RESULTS Identifying key decision makers and how individual practice processes work can save significant recruitment time. Factors identified as assisting practice recruitment included using a personal approach from doctor to doctor, getting buy-in from all practice staff, streamlining the research process to minimize disruption to the practice and flexibility to accommodate practices. CONCLUSIONS The task of recruiting should not be underestimated. Adequate time and resource need to be allocated from the onset. Long periods where practices have no added burdens such as audits, mass vaccination programmes or influenza season are unlikely, therefore there are always considerable challenges in recruiting practices for research. Remaining flexible to individual practice styles and influences and acknowledging the commitment of participants is important.

Factors associated with immunisation coverage and timeliness in New Zealand

BACKGROUND Immunisation coverage in New Zealand is lower than what is necessary to prevent large epidemics of pertussis. Primary care is where most immunisation delivery occurs. General practices vary in their structure and organisation, both in a general sense and specifically with respect to immunisation delivery. AIM To identify the structural and organisational characteristics of general practices associated with higher immunisation coverage and more timely immunisation delivery. DESIGN OF STUDY A random sample of practices during 2005 and 2006. SETTING General practices in the Auckland and Midland regions, with over-sampling of indigenous Maori governance practices. METHOD Practice immunisation coverage and timeliness were measured. Primary care practice characteristics relevant to immunisation delivery by the practice were described. Associations of these practice characteristics with higher practice immunisation coverage and more timely immunisation delivery were determined. RESULTS A total of 124 (61%) of 205 eligible practices were recruited. A median (25th to 75th centile) of 71% (57-77%) of registered children at each practice were fully immunised, and 56% (40-64%) had no immunisation delay. In multivariate analyses, both practice immunisation coverage (P<0.001) and timeliness (P<0.001) decreased with increased social deprivation. After adjustment for socioeconomic deprivation, region, and governance, immunisation coverage and timeliness were better at practices that enrolled children at a younger age (coverage: P = 0.002; timeliness P = 0.007), used one of the four available practice management systems (coverage: P<0.001; timeliness: P = 0.006), and had no staff shortages (coverage: P = 0.027; timeliness: P = 0.021). CONCLUSION Practice immunisation coverage and timeliness vary widely in New Zealand. General organisational and structural aspects of general practices are key determinants of general practice immunisation delivery.

Interim estimates of the effectiveness of seasonal trivalent inactivated influenza vaccine in preventing influenza hospitalisations and primary care visits in Auckland, New Zealand, in 2014.

We present preliminary results of influenza vaccine effectiveness (VE) in New Zealand using a case test-negative design for 28 April to 31 August 2014. VE adjusted for age and time of admission among all ages against severe acute respiratory illness hospital presentation due to laboratory-confirmed influenza was 54% (95% CI: 19 to 74) and specifically against A(H1N1)pdm09 was 65% (95% CI:33 to 81). For influenza-confirmed primary care visits, VE was 67% (95% CI: 48 to 79) overall and 73% (95% CI: 50 to 85) against A(H1N1)pdm09.

Immunization in the print media - perspectives presented by the press.

New Zealand (NZ) has low immunization coverage for a Western country. Media coverage, including views and content expressed on editorial pages, can affect immunization uptake both positively and negatively. The objectives of this research were to analyze the content of written media in 2001 and 2003 throughout NZ in terms of vaccination and vaccine preventable diseases from a supporting, neutral, or opposing perspective; how vaccination and vaccine-preventable diseases are presented to their target audiences; and changes over time with possible influences on these changes. Print media clippings were analyzed from 400 national publications in 2001 and 2003 for references to immunization and vaccine-preventable diseases. Articles were coded as supportive, neutral, or opposing immunization. During two 12-month periods, 2,113 articles, including letters to the editor and opinion columns were analyzed: 1,228 from 2001; and 885 from 2003. Thirty-three percent (704) were classified as “supportive,” 17% (362) as “opposing,” and 51% (1,081) as “neutral.” Articles and perspectives in the media opposed to immunization were significantly more plentiful in 2001 than in 2003 (328/1,228; 27% vs. 34/885; 4% of all immunization media; χ2 = 189.46; p = <0.0001; df = 1). References to specific vaccines and disease were examined. During this study period there were high-profile infectious disease and vaccine issues that may have shaped the differences observed in the media clippings. This study indicates an overall positive trend toward reduction in alarmist anti-immunization messages in media. Strategies implemented by the Immunization Advisory Centre to counter misinformation may have contributed to reduction in anti-immunization messages.

Effectiveness of seasonal influenza vaccination in community-dwelling elderly people: an individual participant data meta-analysis of test-negative design case-control studies

BACKGROUND Several aggregate data meta-analyses have provided estimates of the effectiveness of influenza vaccination in community-dwelling elderly people. However, these studies ignored the effects of patient-level confounders such as sex, age, and chronic diseases that could bias effectiveness estimates. We aimed to assess the confounder-adjusted effectiveness of influenza vaccines on laboratory-confirmed influenza among elderly people by conducting a global individual participant data meta-analysis. METHODS In this individual participant data meta-analysis, we considered studies included in a previously conducted aggregate data meta-analysis that included test-negative design case-control studies published up to July 13, 2014. We contacted all authors of the included studies on Dec 1, 2014, to request individual participant data. Patients were excluded if their unique identifier was missing, their vaccination status was unknown, their outcome status was unknown, or they had had suspected influenza infection more than once in the same influenza season. Cases were patients with influenza-like illness symptoms who tested positive for at least one of A H1N1, A H1N1 pdm09, A H3N2, or B viruses; controls were patients with influenza-like illness symptoms who tested negative for these virus types or subtypes. Influenza vaccine effectiveness against overall and subtype-specific laboratory-confirmed influenza were the primary and secondary outcomes. We used a generalised linear mixed model to calculate adjusted vaccine effectiveness according to vaccine match to the circulating strains of influenza virus and intensity of the virus activity (epidemic or non-epidemic). Vaccine effectiveness was defined as the relative reduction in risk of laboratory-confirmed influenza in vaccinated patients compared with unvaccinated patients. We did subgroup analyses to estimate vaccine effectiveness according to hemisphere, age category, and health status. FINDINGS We received 23 of the 53 datasets included in the aggregate data meta-analysis. Furthermore, six additional datasets were provided by data collaborators, which resulted in individual participant data for a total of 5210 participants. A total of 4975 patients had the required data for analysis. Of these, 3146 (63%) were controls and 1829 (37%) were cases. Influenza vaccination was significantly effective during epidemic seasons irrespective of vaccine match status (matched adjusted vaccine effectiveness 44·38%, 95% CI 22·63-60·01; mismatched adjusted vaccine effectiveness 20·00%, 95% CI 3·46-33·68; analyses in the imputed dataset). Seasonal influenza vaccination did not show significant effectiveness during non-epidemic seasons. We found substantial variation in vaccine effectiveness across virus types and subtypes, with the highest estimate for A H1N1 pdm09 (53·19%, 10·25-75·58) and the lowest estimate for B virus types (-1·52%, -39·58 to 26·16). Although we observed no significant differences between subgroups in each category (hemisphere, age, and health status), influenza vaccination showed a protective effect among elderly people with cardiovascular disease, lung disease, or aged 75 years and younger. INTERPRETATION Influenza vaccination is moderately effective against laboratory-confirmed influenza in elderly people during epidemic seasons. More research is needed to investigate factors affecting vaccine protection (eg, brand-specific or type-specific vaccine effectiveness and repeated annual vaccination) in elderly people. FUNDING University Medical Center Groningen.

Safety of Tdap vaccine in pregnant women: an observational study

Objectives Actively recruit and intensively follow pregnant women receiving a dose of acellular pertussis vaccine for 4 weeks after vaccination. Design and settings A prospective observational study conducted in 2 New Zealand regions. Participants Women in their 28th–38th week of pregnancy, recruited from primary care and antenatal clinics at the time of Tdap administration. Telephone interviews were conducted at 48 h and 4 weeks postvaccination. Main outcomes measures Outcomes were injection site reactions, systemic symptoms and serious adverse events (SAEs). Where available, data have been classified and reported according to Brighton Collaboration definitions. Results 793 women participated with 27.9% receiving trivalent inactivated influenza vaccine concomitantly. 79% of participants reported mild or moderate pain and 2.6% severe pain. Any swelling was reported by 7.6%, induration by 12.0% (collected from 1 site only, n=326), and erythema by 5.8% of participants. Fever was reported by 17 (2.1%) participants, 14 of these occurred within 24 h. Headache, dizziness, nausea, myalgia or arthralgia was reported by <4% of participants, respectively, and fatigue by 8.4%. During the study period, there were 115 adverse events in 113 participants, most of which were minor. At the end of the reporting period, 31 events were classified as serious (eg, obstetric bleeding, hypertension, infection, tachycardia, preterm labour, exacerbation of pre-existing condition and pre-eclampsia). All had variable onset time from vaccination. There were two perinatal deaths. Clinician assessment of all SAEs found none likely to be vaccine related. Conclusions Vaccination with Tdap in pregnant women was well tolerated with no SAE likely to be caused by the vaccine. Trial registration number ACTRN12613001045707.

Febrile events including convulsions following the administration of four brands of 2010 and 2011 inactivated seasonal influenza vaccine in NZ infants and children: The importance of routine active safety surveillance

OBJECTIVE To evaluate and compare rates of febrile events, including febrile convulsion, following immunisation with four brands of inactivated 2010 and 2011 influenza vaccine in NZ infants and children. DESIGN Retrospective telephone surveys of parents of infants and children who received at least one dose of the vaccines of interest. SETTING 184 NZ General Practices who received the vaccines of interest. PARTICIPANTS Recipients of 4088 doses of trivalent inactivated vaccines Fluvax(®), Vaxigrip(®), Influvac(®) and Fluarix(®) and/or monovalent Celvapan. Vaccinees were identified via the electronic Practice Management System and contacted consecutively. MAIN OUTCOME MEASURES Primary outcome was febrile convulsive seizure. Secondary outcomes were presence of fever plus other organ system specific symptoms. RESULTS The parental response rate was 99%. Of 4088 doses given, 865 were Fluvax(®), 2571 Vaxigrip(®), 204 Influvac(®), 438 Fluarix(®) and 10 Celvapan. Three febrile convulsions followed Fluvax(®), a rate of 35 per 10,000 doses. No convulsions occurred following any dose of the other vaccines. There were nine febrile events that included rigors, all following Fluvax(®). Fever occurred significantly more frequently following administration of Fluvax(®) compared with the other brands of vaccines (p<0.0001) and Fluvax recipients were more likely to seek medical attention. Influvac(®) also had higher rates of febrile reactions (OR 0.54, 0.36-0.81) than the other two brands Vaxigrip(®) (OR 0.21, 0.16-0.27) and Fluarix(®) (OR 0.10, 0.05-0.20). After multivariable analysis vaccine, European ethnicity and second dose of vaccine were significantly associated with reporting of fever within 24h of vaccination. CONCLUSIONS Influenza vaccines have different rates of reactogenicity in children which varies between ethnic groups. High rates of febrile convulsions and reactions in children receiving Fluvax(®) and to a lesser extent the higher fever rates in those receiving Influvac(®) compared with the other two brands of influenza vaccines in this study suggests that reactogenicity profiles need to be considered prior to national policy advice each season. The risk-benefit profile in children might not be equally favourable for all licensed paediatric influenza vaccines. More attention needs to be given to comparative research for all trivalent seasonal vaccines, and with all strain changes.

Influenza vaccine effectiveness for hospital and community patients using control groups with and without non-influenza respiratory viruses detected, Auckland, New Zealand 2014.

BACKGROUND We aimed to estimate the protection afforded by inactivated influenza vaccine, in both community and hospital settings, in a well characterised urban population in Auckland during 2014. METHODS We used two different comparison groups, all patients who tested negative for influenza and only those patients who tested negative for influenza and had a non-influenza respiratory virus detected, to calculate the vaccine effectiveness in a test negative study design. Estimates were made separately for general practice outpatient consultations and hospitalised patients, stratified by age group and by influenza type and subtype. Vaccine status was confirmed by electronic record for general practice patients and all respiratory viruses were detected by real time polymerase chain reaction. RESULTS 1039 hospitalised and 1154 general practice outpatient consultations met all the study inclusion criteria and had a respiratory sample tested for influenza and other respiratory viruses. Compared to general practice patients, hospitalised patients were more likely to be very young or very old, to be Māori or Pacific Islander, to have a low income and to suffer from chronic disease. Vaccine effectiveness (VE) adjusted for age and other participant characteristics using all influenza negative controls was 42% (95% CI: 16 to 60%) for hospitalised and 56% (95% CI: 35 to 70%) for general practice patients. The vaccine appeared to be most effective against the influenza A(H1N1)pdm09 strain with an adjusted VE of 62% (95% CI:38 to 77%) for hospitalised and 59% (95% CI:36 to 74%) for general practice patients, using influenza virus negative controls. Similar results found when patients testing positive for a non-influenza respiratory virus were used as the control group. CONCLUSION This study contributes to validation of the test negative design and confirms that inactivated influenza vaccines continue to provide modest but significant protection against laboratory-confirmed influenza.