How strong is the relationship between scabies and acute rheumatic fever? An analysis of neighbourhood factors.

AIM: Recent studies have linked scabies with acute rheumatic fever (ARF). We explored the relationship, by neighbourhood, between permethrin dispensing as an indicator of scabies prevalence and ARF cases over the same period. METHODS: Incident cases of ARF notified to public health between September 2015 and June 2018 and the annual incidence of prescribing by neighbourhood over the same period were analysed. Evidence of an association between permethrin and ARF was obtained by carrying out Poisson regression of the rate of ARF in terms of permethrin rate at the census area unit level, with adjustment for ethnicity and socio-economic deprivation. RESULTS: A total of 413 neighbourhoods were included. The incidence of ARF varied between 0 and 102 per 100 000 people per year (mean 4.3). In contrast, the annual incidence of dispensing of permethrin varied between 0 and 3201 per 100 000 people per year (mean 771). A strong association was observed between the two variables. In an adjusted quasi-Poisson model, permethrin-dispensing rates were strongly associated with ARF incidence, with a change from the 16th to the 84th centile associated with a 16.5-fold increase in incidence (95% confidence interval: 3.82-71.6). CONCLUSIONS: Permethrin prescribing as an indicator of scabies is strongly associated with the incidence of ARF. Considered together with other studies, this evidence suggests that improving scabies control may reduce the burden of ARF in New Zealand.

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.

Scabies is strongly associated with acute rheumatic fever in a cohort study of Auckland children.

AIM: This study sought to determine whether scabies infection is associated with acute rheumatic fever (ARF) or chronic rheumatic heart disease (CRHD). METHODS: A cohort study was undertaken using health records of children aged 3-12 years attending an oral health service for the first time. Subjects were then linked to hospital diagnoses of scabies and ARF or CRHD. RESULTS: A total of 213 957 children free of rheumatic heart disease at baseline were available for analysis. During a mean follow-up time of 5.1 years, 440 children were diagnosed with ARF or CRHD in hospital records. Children diagnosed with scabies during follow-up were 23 times more likely to develop ARF or CRHD, compared with children who had no scabies diagnosis. After adjustment for confounders in a Cox model, the association reduced but remained strong (adjusted hazard ratio: 8.98; 95% confidence interval: 6.33-20.2). In an analysis restricted to children hospitalised at least once during follow-up, the adjusted hazard ratio for the same comparison was 3.43 (95% confidence interval: 1.85-6.37). CONCLUSIONS: A recent diagnosis of scabies from hospital records is strongly associated with a subsequent diagnosis of ARF. Further investigation of the role that scabies infestation may play in the aetiology of ARF is warranted.

Onward transmission of measles virus among vaccinated cases in a large community outbreak in Auckland, New Zealand, 2019.

BACKGROUND: Isolation of cases and quarantining of non-immune contacts are the mainstay of measles outbreak management in elimination settings. Serology testing of exposed contacts may not be feasible in large outbreaks; therefore, vaccination history is used as a proxy for determining immunity to measles and thus prevention of onward virus transmission. This study sought to investigate the risk of measles virus transmission from individuals with a history of one or two doses of measles-containing vaccine (MCV). METHODS:  Retrospective analysis of data from measles cases reported to Auckland Regional Public Health Service during the 2019 Auckland region measles outbreak. Vaccination history was verified using patient records and the New Zealand National Immunisation Register. Onward transmission was determined through case interviews and assessment of exposed contacts. RESULTS:  1451 measles cases were assessed as eligible for vaccination at the time of measles outbreak. Of these, 1015 (70.0%) were unvaccinated, 220 (15.2%) had unknown vaccination status, 139 (9.6%) had received only one dose of MCV and 77 (5.3%) had received two doses of the vaccine. Compared to unvaccinated cases, the odds of onward transmission were lower among those with one dose only (OR 0.41, 95% CI: 0.20-0.75) or two doses of MCV (OR 0.44, 95% CI: 0.17-0.95). Median time since vaccination was longer among those with onward transmission compared to those without onward transmission for one and two doses of the vaccine, suggesting a potential effect of waning immunity among this cohort. CONCLUSION:  These findings support the hypothesis that measles cases with a history of prior vaccination are less likely to transmit the virus to others compared to unvaccinated cases. Such information can be used to support decisions around quarantine requirements for vaccinated contacts in future measles outbreaks.

Invasive pneumococcal disease and serotype emergence in the Auckland region during the vaccine era 2009-16.

INTRODUCTION There is a deficit of knowledge in New Zealand as the epidemiology of invasive pneumococcal disease varies significantly between countries. AIM Time trends and sociodemographic characteristics of cases of invasive pneumococcal disease (IPD) in the Auckland region are reviewed after the introduction of a conjugate vaccination, to provide evidence for future vaccine policy and to ensure Auckland region analysis is representative of national trends for subsequent IPD analysis. METHODS Data on all cases of IPD occurring in Waitemata, Auckland and Counties Manukau District Health Boards between 2009 and 2016 were extracted from EpiSurv. Denominator data were drawn from mid-year estimates supplied by Statistics New Zealand. Descriptive epidemiology and time-series regression was performed to analyse trends. RESULTS Rates of IPD have fallen in the Auckland region over the past 8 years by 32%. While absolute rates in the elderly have reduced by 12%, they have the highest disease burden at 32/100,000. The ethnic disparity continues with Pacific people (33/100,000) and Maori (14/100,000) over represented compared to European (10/100,000). In the elderly, the 19A serotype has increased from an incidence of 0 in 2008 to 8.2/100,000. DISCUSSION Large ethnic and age-related disparities are observed in the Auckland region, consistent with the rest of the country, since the start of the pneumococcal vaccination era. Extending immunisation to the elderly may help close these gaps. As with other countries, there is 19A serotype replacement occurring following conjugate vaccine introduction.