Measuring school level attributable risk to support school-based HPV vaccination programs.

BACKGROUND: In Australia in 2017, 89% of 15-year-old females and 86% of 15-year-old males had received at least one dose of the HPV vaccine. However, considerable variation in HPV vaccination initiation (dose one) across schools remains. It is important to understand the school-level characteristics most strongly associated with low initiation and their contribution to the overall between-school variation. METHODS: A population-based ecological analysis was conducted using school-level data for 2016 on all adolescent students eligible for HPV vaccination in three Australian jurisdictions. We conducted logistic regression to determine school-level factors associated with lower HPV vaccination initiation (< 75% dose 1 uptake) and estimated the population attributable risk (PAR) and the proportion of schools with the factor (school-level prevalence). RESULTS: The factors most strongly associated with lower initiation, and their prevalence were; small schools (OR = 9.3, 95%CI = 6.1-14.1; 33% of schools), special education schools (OR = 5.6,95%CI = 3.7-8.5; 8% of schools), higher Indigenous enrolments (OR = 2.7,95% CI:1.9-3.7; 31% of schools), lower attendance rates (OR = 2.6,95%CI = 1.7-3.7; 35% of schools), remote location (OR = 2.6,95%CI = 1.6-4.3; 6% of schools,) and lower socioeconomic area (OR = 1.8,95% CI = 1.3-2.5; 33% of schools). The highest PARs were small schools (PAR = 79%, 95%CI:76-82), higher Indigenous enrolments (PAR = 38%, 95%CI: 31-44) and lower attendance rate (PAR = 37%, 95%CI: 29-46). CONCLUSION: This analysis suggests that initiatives to support schools that are smaller, with a higher proportion of Indigenous adolescents and lower attendance rates may contribute most to reducing the variation of HPV vaccination uptake observed at a school-level in these jurisdictions. Estimating population-level coverage at the school-level is useful to guide policy and prioritise resourcing to support school-based vaccination programs.

Differences in school factors associated with adolescent HPV vaccination initiation and completion coverage in three Australian states.

BACKGROUND: Schools are the primary setting for the delivery of adolescent HPV vaccination in Australia. Although this strategy has achieved generally high vaccination coverage, gaps persist for reasons that are mostly unknown. This study sought to identify school-level correlates of low vaccination course initiation and completion in New South Wales, Tasmania, and Western Australia to inform initiatives to increase uptake. METHODS: Initiation was defined as the number of first doses given in a school in 2016 divided by vaccine-eligible student enrolments. Completion was the number of third doses given in a school in 2015-2016 divided by the number of first doses. Low initiation and completion were defined as coverage ≤ 25thpercentile of all reporting schools. We investigated correlations between covariates using Spearman's rank correlation coefficients. Due to multicollinearity, we used univariable logistic regression to investigate associations between school characteristics and low coverage. RESULTS: Median initiation was 84.7% (IQR: 75.0%-90.4%) across 1,286 schools and median completion was 93.8% (IQR: 86.0%-97.3%) across 1,295 schools. There were strong correlations between a number of school characteristics, particularly higher Indigenous student enrolments and lower attendance, increasing remoteness, higher postcode socioeconomic disadvantage, and smaller school size. Characteristics most strongly associated with low initiation in univariate analyses were small school size, location in Tasmania, and schools catering for special educational needs. Low completion was most strongly associated with schools in Tasmania and Western Australia, remote location, small size, high proportion of Indigenous student enrolments, and low attendance rates. CONCLUSION: This study provides indicative evidence that characteristics of schools and school populations are associated with the likelihood of low initiation and completion of the HPV vaccination course. The findings will guide further research and help target initiatives to improve vaccination uptake in schools with profiles associated with lower coverage.

Epidemiology of seasonal influenza infection in pregnant women and its impact on birth outcomes.

Seasonal influenza can cause significant morbidity in pregnant women. Much of the existing epidemiological evidence on influenza during pregnancy has focused on the 2009 A/H1N1 pandemic. To measure the epidemiological characteristics of seasonal influenza infection among pregnant women and the impact on infant health, a cohort of 86 779 pregnancies during the influenza season (2012-2014) was established using probabilistic linkage of notifiable infectious disease, hospital admission, and birth information. A total of 192 laboratory-confirmed influenza infections were identified (2·2 per 1000 pregnancies), 14·6% of which were admitted to hospital. There was no difference in the proportion of infections admitted to hospital by trimester or subtype of infection. Influenza B infections were more likely to occur in second trimester compared with influenza A/H3N2 and influenza A/H1N1 infections (41·3%, 23·6%, and 33·3%, respectively), and on average, infants born to women with influenza B during pregnancy had 4·0% (95% CI 0·3-7·6%) lower birth weight relative to optimal compared with infants born to uninfected women (P = 0·03). Results from this linked population-based study suggest that there are differences in maternal infection by virus type and subtype and support the provision of seasonal influenza vaccine to pregnant women.

Comparison of text-messaging to voice telephone interviews for active surveillance of adverse events following immunisation.

OBJECTIVES: In 2013, the Follow-up and Active Surveillance of Trivalent Influenza Vaccine in Mums (FASTMum) program began using short message service (SMS) to collect adverse event information in pregnant women who recently received trivalent influenza vaccine (TIV). This study was designed to compare data collected via SMS and telephone for the purposes of monitoring vaccine safety. METHODS: A number of 344 women who received TIV were randomly assigned to a telephone interview group. They were telephoned seven days post-vaccination and administered a standard survey soliciting any adverse events following immunisation (AEFI) they experienced. They were matched by brand of vaccine, age group, and residence to 344 women who were sent a SMS seven days post-vaccination. The SMS solicited similar information. AEFI reported by SMS and telephone interview were compared by calculating risk ratios. RESULTS: Response rate was higher to SMS compared to telephone interview (90.1% vs. 63.9%). Women who were surveyed by SMS were significantly less likely to report an AEFI compared to women who were surveyed by telephone (RR: 0.41; 95% CI: 0.29-0.59). The greatest discrepancies between SMS and telephone interview were for self-reported injection site reactions (3.1% vs. 16.8%) and unsolicited (or "other") events (11.4% vs. 4.1%). Data collected by SMS was significantly timelier. CONCLUSIONS: Data collection by SMS results in significantly improved response rates and timeliness of vaccine safety data. Systems which incorporate SMS could be used to more rapidly detect safety signals and promote more rapid public health response to vaccine quality issues.

EbolaTracks: an automated SMS system for monitoring persons potentially exposed to Ebola virus disease.

We report development and implementation of a short message service (SMS)-based system to facilitate active monitoring of persons potentially exposed to Ebola virus disease (EVD), whether returning from EVD-affected countries, or contacts of local cases, should they occur. The system solicits information on symptoms and temperature twice daily. We demonstrated proof-of-concept; however this system would likely be even more useful where there are many local contacts to confirmed EVD cases or travellers from EVD-affected countries.

Epidemiological study of severe febrile reactions in young children in Western Australia caused by a 2010 trivalent inactivated influenza vaccine.

BACKGROUND: The 2010 influenza vaccination program for children aged 6 months to 4 years in Western Australia (WA) was suspended following reports of severe febrile reactions, including febrile convulsions, following vaccination with trivalent inactivated influenza vaccine (TIV). METHODS: To investigate the association between severe febrile reactions and TIV, three studies were conducted: (i) rates of febrile convulsions within 72 h of receiving TIV in 2010 were estimated by vaccine formulation and batch; (ii) numbers of children presenting to hospital emergency departments with febrile convulsions from 2008 to 2010 were compared; and (iii) a retrospective cohort study of 360 children was conducted to compare the reactogenicity of available TIV formulations. FINDINGS: In 2010, an estimated maximum of 18,816 doses of TIV were administered and 63 febrile convulsions were recorded, giving an estimated rate of 3.3 (95% CI 2.6 to 4.2) per 1000 doses of TIV administered. The odds of a TIV-associated febrile convulsion was highly elevated in 2010 (p<0.001) and was associated with the vaccine formulations of one manufacturer-Fluvax and Fluvax Junior (CSL Biotherapies). The risk of both febrile convulsions (p<0.0001) and other febrile reactions (p<0.0001) was significantly greater for Fluvax formulations compared to the major alternate brand. The risk of febrile events was not associated with prior receipt of TIV or monovalent 2009 H1N1 pandemic vaccine. The biological cause of the febrile reactions is currently unknown. INTERPRETATION: One brand of influenza vaccine was responsible for the increase in febrile reactions, including febrile convulsions. Until the biological reason for this is determined and remediation undertaken, childhood influenza vaccination programs should not include Fluvax-type formulations and enhanced surveillance for febrile reactions in children receiving TIV should be undertaken.

Secondary attack rate of pandemic influenza A(H1N1) 2009 in Western Australian households, 29 May-7 August 2009.

Understanding household transmission of the pandemic influenza A(H1N1)2009 virus, including risk factors for transmission, is important for refining public health strategies to reduce the burden of the disease. During the influenza season of 2009 we investigated transmission of the emerging virus in 595 households in which the index case was the first symptomatic case of influenza A(H1N1)2009. Secondary cases were defined as household contacts with influenza-like illness (ILI) or laboratory-confirmed influenza A(H1N1)2009, occurring at least one day after but within seven days following symptom onset in the index case. ILI developed in 231 of the 1,589 household contacts, a secondary attack rate of 14.5% (95% confidence interval (CI): 12.9­16.4). At least one secondary case occurred in 166 of the 595 households (a household transmission rate of 27.9%; 95% CI: 24.5­31.6).Of these, 127 (76.5%) households reported one secondary case and 39 (23.5%) households reported two or more secondary cases. Secondary attack rates were highest in children younger than five years (p=0.001), and young children were also more efficient transmitters (p=0.01). Individual risk was not associated with household size. Prophylactic antiviral therapy was associated with reduced transmission (p=0.03). The secondary attack rate of ILI in households with a confirmed pandemic influenza A(H1N1)2009 index case was comparable to that described previously for seasonal influenza.

Quantifying benefits and risks of vaccinating Australian children aged six months to four years with trivalent inactivated seasonal influenza vaccine in 2010.

Australian and New Zealand health authorities identified seasonal trivalent inactivated influenza vaccines manufactured by CSL Biotherapies as the probable cause of increased febrile convulsions in children under five within 24 hours of vaccination and recommended against their use in this age group. We quantified the benefit-risk profile of the CSL vaccines using the number needed to vaccinate and suggest they might have caused two to three hospital admissions due to febrile convulsions for every hospital admission due to influenza prevented.

Association between 2009 seasonal influenza vaccine and influenza-like illness during the 2009 pandemic: preliminary results of a large household transmission study in Western Australia.

We conducted a prospective household transmission study to examine whether receipt of 2009 trivalent influenza vaccine (TIV) was associated with increased risk of influenza-like illness (ILI) among contacts of confirmed pandemic influenza A(H1N1) 2009 patients. In the week following onset of pandemic illness in a household member, 46 (15%) of 304 TIV-vaccinated contacts, and 174 (15%) of 1,162 unvaccinated contacts developed ILI (p=0.95). Receipt of 2009 TIV had no effect on one's risk of pandemic illness.

Homology of complete genome sequences for dengue virus type-1, from dengue-fever- and dengue-haemorrhagic-fever-associated epidemics in Hawaii and French Polynesia.

Dengue epidemic virulence is thought to be conferred by various factors, including the genotype of the virus involved. Increased or decreased epidemic virulence has been associated not only with the introduction of type-2 (DENV-2) strains into the South Pacific, the Caribbean and South America, but also with newly emergent DENV-3 genotypes in Sri Lanka, and the year-to-year variation in the DENV-4 strains circulating in Puerto Rico. These observations indicate that there are inherent differences among viral genotypes in their capacity to induce severe disease, that is, their virulence potential. The present study involved a comparison of the complete genome sequences of DENV-1 viruses that had been isolated from cases of dengue fever (DF) or dengue haemorrhagic fever (DHF) that occurred in French Polynesia or Hawaii in 2001, when a virulent DHF-associated dengue epidemic was occurring throughout the Pacific region. Previous studies have identified putative virulence-associated motifs and substitutions in the DENV-2 genome, and the main aim of the present study was to identify similar changes in DENV-1 that may be associated with viral virulence. As no virulence determinants were seen, however, in any gene or untranslated region, it appears that genotype is not the sole determinant of virulence in DENV-1. Further studies, to compare DF- and DHF-associated strains of DENV-1 isolated from epidemics of variable virulence, in the same eco-biological context, are needed.

International foodborne outbreak of Shigella sonnei infection in airline passengers.

During 22-24 August 2004, an outbreak of Shigella sonnei infection affected air travellers who departed from Hawaii. Forty-seven passengers with culture-confirmed shigellosis and 116 probable cases who travelled on 12 flights dispersed to Japan, Australia, 22 US states, and American Samoa. All flights were served by one caterer. Pulsed-field gel electrophoresis of all 29 S. sonnei isolates yielded patterns that matched within one band. Food histories and menu reviews identified raw carrot served onboard as the likely vehicle of infection. Attack rates for diarrhoea on three surveyed flights with confirmed cases were 54% (110/204), 32% (20/63), and 12% (8/67). A total of 2700 meals were served on flights with confirmed cases; using attack rates observed on surveyed flights, we estimated that 300-1500 passengers were infected. This outbreak illustrates the risk of rapid, global spread of illness from a point-source at a major airline hub.

Molecular epidemiology of dengue in the Pacific: introduction of two distinct strains of dengue virus type-1 [corrected] into Hawaii.

In 2000, a major dengue epidemic, caused by the type-1 virus (DENV-1), began in the Pacific and Asia, with cases still being reported in 2006. The phylogenetic analysis of full-length sequences of the envelope-protein gene of DENV-1 isolates recovered during outbreaks in Hawaii and Tahiti in 2001-2002 indicated that most Hawaiian isolates were Tahitian in origin. All the Hawaiian and Tahitian isolates were identified as the Pacific subtype (i.e. subtype IV) of DENV-1. A Hawaiian isolate, collected from a resident who had travelled to Samoa, differed significantly at the nucleotide level, however, from all the other Hawaiian strains, clustering, in the phylogenetic analysis, with a virus previously isolated from another visitor to Samoa. These results not only indicate that two distinct strains of DENV-1 were introduced into Hawaii in 2001 but also illustrate the ease with which dengue can be carried across distances of many thousands of miles.

Influenza and pneumococcal vaccination coverage levels among Hawaii statewide long-term-care facilities.

Influenza and pneumococcal vaccination rates among Hawaii long-term-care facilities (LTCFs) statewide during the 1996/97 through the 1998/99 influenza seasons revealed that resident influenza vaccination rates remained over 89%, but pneumococcal vaccination was underutilized. LTCF staff influenza vaccination rates over the same time period were low.

The effect of a combined influenza/pneumococcal immunization reminder letter.

BACKGROUND: The effect of a combined influenza and pneumococcal immunization reminder letter on increasing influenza and pneumococcal immunization rates, and the timeliness of receiving immunizations after receipt of a reminder letter, have not been examined. This study addresses these issues using a sample of new Medicare beneficiaries residing in Hawaii. METHODS: Newly enrolled Medicare beneficiaries in Hawaii from 25 September 1995 through 31 August 1996 were randomly assigned to one of three groups: Group 1, no letter (n=2144); Group 2, influenza immunization reminder letter only (n=2213); or Group 3, pneumococcal and influenza immunization reminder letter (n=2171). Health Care Financing Administration claims data were compared among groups. RESULTS: In Group 3, the influenza immunization rate increased 3.8 percentage points (n=87; p=0.017) compared with Group 1. The Group 3 pneumococcal immunization rate increased 3.5 percentage points (n=78; p<0.001) compared to Group 1 and 4.0 percentage points (n=86; p<0.001) compared to Group 2. Sixty-six beneficiaries in Group 3 received simultaneous pneumococcal and influenza immunizations, a significant difference compared to Group 1 or Group 2. Increases in immunizations were observed immediately following the reminder letters and the effect persisted for 5 to 7 weeks. CONCLUSIONS: The combination letter increased both influenza and pneumococcal immunization rates and the simultaneous administration of immunizations without detrimental effect to influenza immunization rates. A combined reminder letter is inexpensive and recommended as part of a multicomponent campaign for adult immunization.

Assessment of the clinical presentation and treatment of 353 cases of laboratory-confirmed leptospirosis in Hawaii, 1974-1998.

Leptospirosis is frequently misdiagnosed as a result of its protean and nonspecific presentation. Leptospirosis, a zoonosis with global distribution, commonly occurs in tropical and subtropical regions; most reported cases in the United States occur in Hawaii. All laboratory-confirmed leptospirosis cases in the State of Hawaii from 1974 through 1998 (n=353) were clinically evaluated. The most common presentation involved nonspecific signs or symptoms, including fever, myalgia, and headache. Jaundice occurred in 39% of cases; conjunctival suffusion was described in 28% of these cases. Initiation of antibiotics before the seventh day of symptoms was associated with a significantly shortened duration of illness. Because early recognition and initiation of antibiotic therapy are important, clinicians should familiarize themselves with the clinical presentation of leptospirosis, and when evaluating a patient with a febrile illness, they should obtain exposure and travel histories and entertain the possibility of leptospirosis in the differential diagnosis.

Hepatitis C, diagnosis and management: a survey of practicing physicians in Hawaii.

We surveyed 652 Hawaii physicians who diagnosed hepatitis C (HCV) since 1997. Less than 20% of licensed physicians have diagnosed HCV and initial estimates suggest there are 12,000 to 18,000 undiagnosed HCV cases in Hawaii. Treatment is concentrated among twelve physicians and aggressive case finding may overwhelm present resources. More primary care physicians need to participate in the detection and management of HCV.

Sporadic Campylobacter jejuni infections in Hawaii: associations with prior antibiotic use and commercially prepared chicken.

Campylobacter is the most common cause of bacterial foodborne illness in the United States, and Hawaii has the highest rate of Campylobacter jejuni infections in the nation. A case-control study was conducted to determine indigenous exposures that contribute to the high incidence of sporadic C. jejuni infection in Hawaii. A total of 211 case patients with diarrhea and confirmed Campylobacter infection was enrolled, along with 1 age- and telephone exchange-matched control subject for each patient. Participants were interviewed about illness, medicines, food consumption, food-handling practices, and exposure to animals. In matched logistic regression analyses, eating chicken prepared by a commercial food establishment in the 7 days before case illness onset (adjusted odds ratio [AOR], 1.8; P=.03) and consuming antibiotics during the 28 days before illness onset (AOR, 3.3; P=.03) were significant independent predictors of illness. Further study of the association of Campylobacter illness with commercially prepared chicken and prior antibiotic use is needed.

Diarrhea-associated hospitalizations among children in Hawaii.

OBJECTIVE: To estimate the burden of diarrhea-associated hospitalizations among children in Hawaii. DESIGN: Retrospective analysis of hospital discharge records. PATIENTS: Children from 1 month through 4 years of age with a diarrhea-associated diagnosis listed on the hospital discharge record in Hawaii. SETTING: Acute care hospitals in the state of Hawaii, 1994 through 1997. RESULTS: During 1994-1997, 2288 children (11.3% of all hospitalizations for children < 5 years of age) had a diarrhea-associated diagnosis listed at hospital discharge. The average annual incidence (per 10,000 children) of diarrhea-associated hospitalizations was 62.3; the incidence was higher for children < 1 year (101.6) than for those 1 through 4 years of age (52.7). Rates for Hawaii were lower than national rates during 1993 through 1995 (US annual rate of 89 per 10,000 children). The median length of hospital stay was 2 days for diarrhea-associated hospitalizations, and 3 days for hospitalizations specifically associated with rotavirus-related diarrhea. Diarrhea-associated hospitalizations were highest during the period December through June. CONCLUSIONS: Diarrhea is an important cause of hospitalization among children in Hawaii, where approximately 1 in 32 children may be hospitalized by 5 years of age. The age-specific and temporal trends reported here are consistent with those previously described for rotavirus-associated hospitalizations, suggesting that this pathogen is a major contributor to the overall morbidity from diarrhea.

Kawasaki syndrome hospitalizations among children in Hawaii and Connecticut.

OBJECTIVES: To estimate the incidence and describe recent trends of Kawasaki syndrome (KS) in 2 different areas of the United States. METHODS: Retrospective analysis of Hawaii and Connecticut State KS hospital discharge records for children younger than 5 years. RESULTS: In Hawaii, 175 KS hospitalizations for children younger than 5 years were reported during 1994 through 1997; the annual hospitalization rate per 100,000 children was 47.7. The rate for Hawaiian children younger than 1 year (83.2) was greater than that for 1- to 4-year-old children (39.0), and most hospitalizations occurred prior to age 2 years (median age, 17 months). In Connecticut, 171 KS hospitalizations for children younger than 5 years were reported during 1993 through 1996; the annual hospitalization rate per 100,000 children was 18.8, and the median age at hospitalization was 28 months. For both states, most hospitalizations were for boys. Although no clear seasonality was apparent, monthly peaks occurred in some of the years from December through March. CONCLUSIONS: Kawasaki syndrome seems to remain an endemic disease in the United States. A high KS annual hospitalization rate was seen in Hawaii, especially in children younger than 1 year, whereas in Connecticut, the KS rate was more consistent with those previously reported in the continental United States. Arch Pediatr Adolesc Med. 2000;154:804-808

Evaluation of the indirect hemagglutination assay for diagnosis of acute leptospirosis in Hawaii.

Timely diagnosis of leptospirosis is important to ensure a favorable clinical outcome. The definitive serologic assay, the microscopic agglutination test (MAT), requires paired sera and is not useful for guiding early clinical management. The only screening test approved for use in the United States, the indirect hemagglutination assay (IHA), has not undergone extensive field evaluation. To assess the performance of the leptospirosis IHA in Hawaii, serum from patients evaluated for leptospirosis between 1992 and 1997 were tested with the IHA at the Hawaii State Laboratories Division and with the MAT at the Centers for Disease Control and Prevention. Leptospirosis was considered confirmed by a fourfold rise in MAT titer and/or a positive culture. A total of 92 (41%) of 226 specimens from 114 persons with confirmed leptospirosis were found positive by IHA. Only 18 (15%) of 119 specimens obtained within 14 days of onset were IHA positive, compared to 74 (69%) of 107 specimens collected more than 14 days after onset (P <0.001). Repeat testing ultimately resulted in 78 (68%) of the confirmed cases having at least one specimen found positive by IHA. Thirteen different presumptive infecting serogroups were identified among 251 specimens with an MAT titer of >/=200 and obtained from persons with confirmed or probable leptospirosis. Fifty (68%) of 73 specimens with Icterohaemorrhagiae as the presumptive infecting serogroup were found positive by IHA, compared to 44 (47%) of 93 specimens with Australis as the presumptive infecting serogroup (P, 0.01). The IHA test was positive for 3 (1%) of 236 specimens from 154 persons without leptospirosis. The sensitivity of the leptospirosis IHA in Hawaii was substantially below figures reported previously, particularly early in the course of illness, limiting its usefulness for diagnosing acute infection. Since the presumptive infecting serogroup affected IHA results and the prevalence of serovars varies with geography, the performance of the IHA should be assessed locally. More sensitive leptospirosis screening tests are needed in Hawaii.