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.

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.

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.

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.

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.

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.

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.

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.

HIV-1 infection among female commercial sex workers in rural Thailand.

OBJECTIVE: To reconstruct past HIV-1 incidence and identify risk factors for HIV-1 seroconversion among female commercial sex workers in a semi-rural setting in northern Thailand. DESIGN: Retrospective cohort of sex workers attending a sexually transmitted disease (STD) clinic at Mae Chan District Hospital, Chiang Rai Province, Thailand. METHODS: Information included demographic data, HIV-1 antibody testing and STD diagnosis was collected in 821 sex workers attending the STD clinic from 1989 through 1993. HIV-1 incidence among initially HIV-1-seronegative sex workers who underwent repeat HIV-1 antibody testing during follow-up was determined and possible predictive factors for seroconversion including diagnosis of other STD were examined. RESULTS: HIV-1 seroprevalence among 556 sex workers who underwent antibody testing was 52%, rising from 29% at initial test in 1989 to 53-63% for 1990-1993. Among 96 initially HIV-1-negative sex workers who underwent repeat testing, 64 HIV-1 seroconversions occurred, giving an incidence rate of 12.6/100 person months (PM). Incidence increased from 12.0/100 PM for 1989 and 1990 to 17.0/100 PM for 1991, with a subsequent decline to 9.3/100 PM for 1992-1993. The cumulative risk of seroconversion 6 months following initial negative HIV-1 antibody test was 57%. There were higher rates among younger sex workers (14-19 years old) and those from Hilltribes, but only a diagnosis of chancroid was significantly associated with HIV-1 seroconversion (P = 0.014). CONCLUSION: An explosive epidemic of HIV-1 occurred among sex workers in a semi-rural area of northern Thailand from 1989. These HIV-1 incidence estimates, which are among the highest rates of sexual transmission ever reported, highlight the extreme vulnerability of female sex workers to HIV infection, even in a non-urban setting.

PIP: A retrospective study of 821 commercial sex workers attending a sexually transmitted disease (STD) clinic in northern Thailand's Chiang Rai Province from 1989 to 1993 revealed an explosive epidemic of human immunodeficiency virus (HIV). The overall seroprevalence among the 556 women for whom antibody tests were available was 52.3%. However, a dramatic increase in HIV-1 seroprevalence occurred from 1989 (29.3%) to 1990 (54.1%), followed by a leveling off through 1993. Among the 96 (36.2%) initial seronegatives who underwent subsequent testing, 64 seroconverted over a mean follow-up period of 5.9 months, yielding an incidence rate of 12.6/100 person-months. Incidence increased from 12.0/100 person-months in 1989 and 1990 to 17.0/100 person-months for 1991, and then declined to 9.3/100 person-months in 1992-93. The cumulative risk of seroconversion was 57% at 6 months after initial testing and 77% after 12 months. Diagnosis of chancroid during follow up was the only factor significantly associated with seroconversion. Although the retrospective nature of this study limits analysis of predictors of HIV infection in this population, the findings suggest a need for improved STD management.

HIV and AIDS in Asia and the Pacific: an epidemiological overview.

PIP: The authors define for the purpose of this overview Asia and the Pacific to be the 46 countries and other administrative areas belonging to the Southeast Asia and Western Pacific regions of the World Health Organization. Defined as such, 55% of the world's population lives in the Asia-Pacific region. China, India, and Indonesia, three of the four most populous countries in the world, are part of the region. The region is highly diverse with highly diverse systems in place to monitor the course of the HIV epidemic. This diversity makes it difficult to develop an accurate picture of the epidemiology of HIV and AIDS in Asia and the Pacific. Despite underreporting and data of varying quality, one may reasonably conclude on the basis of available evidence that countries overall in Asia and the Pacific are in a relatively early stage of the HIV/AIDS epidemic. Reported modes of transmission vary widely and include heterosexual sexual contact, homosexual sexual contact, IV drug use, the receipt of blood products, and mother-to-child transmission. A cumulative total of 851,628 AIDS cases had been reported to the World Health Organization (WHO) by December 31, 1993. Reports from the Asia-Pacific region represent 1% of that total. The WHO estimates that there have been more than 3 million AIDS cases and 14 million infections in adults worldwide since the beginning of the epidemic, while other estimates are substantially higher. The Asia-Pacific region accounts for 3% of the estimated AIDS cases, but 15% of the total estimated HIV infections, indicating the relatively recent arrival of the epidemic to that part of the world. The authors discuss HIV case reporting, surveys of HIV prevalence, risk factors for HIV infection, geographic patterns of HIV transmission, molecular and clinical epidemiology, and the future of the HIV epidemic in Asia and the Pacific.^ieng

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.

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.

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

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.

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.

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.

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.

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.