Risk Factors and Attack Rates of Seasonal Influenza Infection: Results of the Southern Hemisphere Influenza and Vaccine Effectiveness Research and Surveillance (SHIVERS) Seroepidemiologic Cohort Study.

Background: Understanding the attack rate of influenza infection and the proportion who become ill by risk group is key to implementing prevention measures. While population-based studies of antihemagglutinin antibody responses have been described previously, studies examining both antihemagglutinin and antineuraminidase antibodies are lacking. Methods: In 2015, we conducted a seroepidemiologic cohort study of individuals randomly selected from a population in New Zealand. We tested paired sera for hemagglutination inhibition (HAI) or neuraminidase inhibition (NAI) titers for seroconversion. We followed participants weekly and performed influenza polymerase chain reaction (PCR) for those reporting influenza-like illness (ILI). Results: Influenza infection (either HAI or NAI seroconversion) was found in 321 (35% [95% confidence interval, 32%-38%]) of 911 unvaccinated participants, of whom 100 (31%) seroconverted to NAI alone. Young children and Pacific peoples experienced the highest influenza infection attack rates, but overall only a quarter of all infected reported influenza PCR-confirmed ILI, and one-quarter of these sought medical attention. Seroconversion to NAI alone was higher among children aged <5 years vs those aged ≥5 years (14% vs 4%; P < .001) and among those with influenza B vs A(H3N2) virus infections (7% vs 0.3%; P < .001). Conclusions: Measurement of antineuraminidase antibodies in addition to antihemagglutinin antibodies may be important in capturing the true influenza infection rates.

Effectiveness of a group B outer membrane vesicle meningococcal vaccine against gonorrhoea in New Zealand: a retrospective case-control study.

BACKGROUND: Gonorrhoea is a major global public health problem that is exacerbated by drug resistance. Effective vaccine development has been unsuccessful, but surveillance data suggest that outer membrane vesicle meningococcal group B vaccines affect the incidence of gonorrhoea. We assessed vaccine effectiveness of the outer membrane vesicle meningococcal B vaccine (MeNZB) against gonorrhoea in young adults aged 15-30 years in New Zealand. METHODS: We did a retrospective case-control study of patients at sexual health clinics aged 15-30 years who were born between Jan 1, 1984, and Dec 31, 1998, eligible to receive MeNZB, and diagnosed with gonorrhoea or chlamydia, or both. Demographic data, sexual health clinic data, and National Immunisation Register data were linked via patients' unique personal identifier. For primary analysis, cases were confirmed by laboratory isolation or detection of Neisseria gonorrhoeae only from a clinical specimen, and controls were individuals with a positive chlamydia test only. We estimated odds ratios (ORs) comparing disease outcomes in vaccinated versus unvaccinated participants via multivariable logistic regression. Vaccine effectiveness was calculated as 100×(1-OR). FINDINGS: 11 of 24 clinics nationally provided records. There were 14 730 cases and controls for analyses: 1241 incidences of gonorrhoea, 12 487 incidences of chlamydia, and 1002 incidences of co-infection. Vaccinated individuals were significantly less likely to be cases than controls (511 [41%] vs 6424 [51%]; adjusted OR 0·69 [95% CI 0·61-0·79]; p<0·0001). Estimate vaccine effectiveness of MeNZB against gonorrhoea after adjustment for ethnicity, deprivation, geographical area, and sex was 31% (95% CI 21-39). INTERPRETATION: Exposure to MeNZB was associated with reduced rates of gonorrhoea diagnosis, the first time a vaccine has shown any protection against gonorrhoea. These results provide a proof of principle that can inform prospective vaccine development not only for gonorrhoea but also for meningococcal vaccines. FUNDING: GSK Vaccines.

Outreach immunisation services in NewZealand: a review of service delivery models.

INTRODUCTION Outreach Immunisation Services (OIS) enable children who have not been immunised on time at general practice to be immunised in the community, thereby improving immunisation coverage and reducing equity gaps. AIM To identify the most effective service delivery models and make recommendations for more effective and cost-efficient OIS delivery in New Zealand. METHODS Data collection and thematic analysis through a detailed review of OIS contracts and service specifications, an online survey and in-depth interviews with stakeholders and providers, and an analysis of cost data was conducted. RESULTS In total, 28 OIS providers completed survey questionnaires, 28 OIS staff were interviewed, and cost effectiveness data were obtained from 11 providers. The surveys and interviews identified key themes around identifying clients with the highest needs, effective engagement strategies, staffing requirements, and service challenges. On average, each OIS referral costs NZ$361 (median NZ$257), and each vaccination event costs NZ$636, ranging from NZ$145 to NZ$2403. Characteristics for two separate models of service delivery were identified based on provider size. CONCLUSION There is considerable range in costs and style of OIS delivery, and efficiencies can be gained. Models need to fit with locality needs and include adequate resourcing, staff with good local knowledge, close relationships with other key child health services and preferably co-location, sustainable funding, and regular service reviews. OIS are part of an effective integrated service that relies on accurate data, positive relationships and a rapid response when children fail to present for vaccination in a timely fashion.