Participant centred safety surveillance of health care workers receiving influenza vaccination.

Following the introduction of mandatory influenza vaccination for staff working in high risk clinical areas in 2018, we conducted active surveillance for adverse events following immunisation utilising an automated online survey to vaccine recipients at three and 42 days post immunisation. Most participants 2285 (92%) agreed to participate; 515 (32%) staff reported any symptom and eight (1.6%) sought medical attention. The odds of having a reaction decreased with age by approximately 2% per year. The system was acceptable to staff, and the data demonstrated rates of reported symptoms within expected rates for influenza vaccines from clinical trials. Rates of medical attendance were similar to previous surveillance. Participant centred real-time safety surveillance proved useful in this staff influenza vaccination context, providing reassurance with expected rates and profile of common adverse events following staff influenza vaccination.

Estimating the critical immunity threshold for preventing hepatitis A outbreaks in men who have sex with men.

Several outbreaks of hepatitis A in men who have sex with men (MSM) were reported in the 1980s and 1990s in Australia and other countries. An effective hepatitis A virus (HAV) vaccine has been available in Australia since 1994 and is recommended for high-risk groups including MSM. No outbreaks of hepatitis A in Australian MSM have been reported since 1996. In this study, we aimed to estimate HAV transmissibility in MSM populations in order to inform targets for vaccine coverage in such populations. We used mathematical models of HAV transmission in a MSM population to estimate the basic reproduction number (R 0) and the probability of an HAV epidemic occurring as a function of the immune proportion. We estimated a plausible range for R 0 of 1·71-3·67 for HAV in MSM and that sustained epidemics cannot occur once the proportion immune to HAV is greater than ~70%. To our knowledge this is the first estimate of R 0 and the critical population immunity threshold for HAV transmission in MSM. As HAV is no longer endemic in Australia or in most other developed countries, vaccination is the only means of maintaining population immunity >70%. Our findings provide impetus to promote HAV vaccination in high-risk groups such as MSM.

High burden of RSV hospitalization in very young children: a data linkage study.

Linked administrative population data were used to estimate the burden of childhood respiratory syncytial virus (RSV) hospitalization in an Australian cohort aged <5 years. RSV-coded hospitalizations data were extracted for all children aged <5 years born in New South Wales (NSW), Australia between 2001 and 2010. Incidence was calculated as the total number of new episodes of RSV hospitalization divided by the child-years at risk. Mean cost per episode of RSV hospitalization was estimated using public hospital cost weights. The cohort comprised of 870 314 children. The population-based incidence/1000 child-years of RSV hospitalization for children aged <5 years was 4·9 with a rate of 25·6 in children aged <3 months. The incidence of RSV hospitalization (per 1000 child-years) was 11·0 for Indigenous children, 81·5 for children with bronchopulmonary dysplasia (BPD), 10·2 for preterm children with gestational age (GA) 32-36 weeks, 27·0 for children with GA 28-31 weeks, 39·0 for children with GA <28 weeks and 6·7 for term children with low birthweight. RSV hospitalization was associated with an average annual cost of more than AUD 9 million in NSW. RSV was associated with a substantial burden of childhood hospitalization specifically in children aged <3 months and in Indigenous children and children born preterm or with BPD.

Transmission of hepatitis C virus to recipients of parenteral vitamin therapy in a primary care facility.

BACKGROUND AND OBJECTIVES: The Australian prevalence of hepatitis C virus (HCV) is approximately 1%, with the majority of cases acquired through injecting drug use. However, occasionally HCV infection occurs in healthcare settings. Three new HCV infections were identified amongst patients attending a general practice in Sydney, Australia, specialising in parenteral vitamin therapy. STUDY DESIGN: An investigation was conducted to identify the source of infection and mechanism of transmission. Molecular analysis was conducted by sequencing the HCV NS5A, Core and NS5B regions. RESULTS: Two sources were identified using molecular epidemiology - a genotype 3a case was the source for a case acquired in late 2004 and a genotype 1b case the source for one case acquired in late 2006 and another in early 2007. The common risk factor was parenteral vitamin C therapy. CONCLUSIONS: Inadequate infection control was apparent and likely to have resulted in blood contamination of the healthcare workers, their equipment, the clinic environment and parenteral medications. Molecular and clinical epidemiology clearly identified parenteral transmission of HCV, highlighting the risks of blood contamination of parenteral equipment and use of multi-dose flasks on more than one patient.

The association of respiratory viruses, temperature, and other climatic parameters with the incidence of invasive pneumococcal disease in Sydney, Australia.

BACKGROUND: Increases in incidence of invasive pneumococcal disease (IPD) during the colder months of the year in temperate regions are well recognized, but few detailed studies of possible interactions are available. We examined the relationship between virus activity, climatic parameters, and IPD during a winter in which there were separate peak incidences of influenza and respiratory syncytial virus (RSV) infection. METHODS: We performed an ecological study that correlated population-based data on IPD and respiratory virus activity in the year 2000 in metropolitan New South Wales, Australia, with climatic parameters, including weekly mean maximum and minimum temperature, relative humidity, rainfall, and wind speed. RESULTS: In children, RSV activity was significantly positively correlated with IPD activity (r = 0.578; P = .002) but not with influenza virus activity. There was a weak inverse relationship between parainfluenza virus activity and IPD activity (r = -0.401; P = .043) and a stronger inverse relationship between weekly mean maximum temperature (r = -0.458; P = .001), weekly mean minimum temperature (r = -0.437; P = .001), and IPD activity. In adults, there was no significant correlation between RSV or influenza virus activity alone and IPD, but the combination of RSV and influenza was significantly correlated with IPD (r = 0.481; P = .013). CONCLUSIONS: This study suggests that RSV infection and influenza contribute to IPD incidence peaks differently for children than for adults. Data from other geographic areas and more rigorous study designs are required to confirm these findings.

Designated "no smoking" areas provide from partial to no protection from environmental tobacco smoke.

OBJECTIVE: To determine the efficacy of designated "no smoking" areas in the hospitality industry as a means of providing protection from environmental tobacco smoke (ETS), and whether certain design features assist in achieving this end. METHODOLOGY: In the greater metropolitan region of Sydney, a representative group of 17 social and gaming clubs, licensed to serve alcoholic beverages and in which, apart from designated areas, smoking occurs, agreed to participate. In each establishment, simultaneous single measurements of atmospheric nicotine, particulate matter (10 microm; PM10) and carbon dioxide (CO2) levels were measured in a general use area and in a designated "no smoking" area during times of normal operation, together with the levels in outdoor air (PM10 and CO2 only). Analyses were made of these data to assess the extent to which persons using the "no smoking" areas were protected from exposure to ETS. RESULTS: By comparison with levels in general use areas, nicotine and particulate matter levels were significantly less in the "no smoking" areas, but were still readily detectable at higher than ambient levels. For nicotine, mean (SD) levels were 100.5 (45.3) microg/m3 in the areas where smoking occurred and 41.3 (16.1) microg/m3 in the "no smoking" areas. Corresponding PM10 levels were 460 (196) microg/m3 and 210 (210) microg/m3, while outdoor levels were 61 (23) microg/m3. The reduction in pollutants achieved through a separate room being designated "no smoking" was only marginally better than the reduction achieved when a "no smoking" area was contiguous with a smoking area. CO2 levels were relatively uninformative. CONCLUSION: Provision of designated "no smoking" areas in licensed (gaming) clubs in New South Wales, Australia, provides, at best, partial protection from ETS-typically about a 50% reduction in exposure. The protection afforded is less than users might reasonably have understood and is not comparable with protection afforded by prohibiting smoking on the premises.

Varicella vaccine in post-exposure prophylaxis.

Evidence concerning the effectiveness of Oka-based varicella vaccines when administered following exposure to varicella zoster virus in domestic and hospital settings is reviewed. The evidence appears to support post-exposure use of Oka-derived varicella vaccines in children within 3 days of rash onset in the index case. Despite vaccination, a small proportion will develop mild, but infectious, chickenpox, especially if they have been exposed in the household setting. Controlled studies of post-exposure prophylaxis in adults using both Varilrix and Varivax II are still needed. The applicability of this approach to disease control in health care facilities and in community settings warrants wider discussion.

Typhoid and paratyphoid fever in south-eastern Sydney, 1992-1997.

Notification records of typhoid and paratyphoid cases among residents of south-eastern Sydney during 1992-1997 were reviewed, with particular attention paid to identifying a source of infection and to completeness of follow up. Notifications comprised 30 cases of Salmonella Typhi, nine of S. Paratyphi A and five of S. Paratyphi B. These 44 cases had a median age of 20 years (range 2-62). Of the 39 cases with known country of birth, 30 were born overseas, predominantly in Asian countries. Of 39 cases with a known travel history, 33 were cases of overseas-acquired acute infection and two cases were asymptomatic chronic carriers. A source was identified in only one of four domestically acquired infections. Of eight household contacts in occupations posing a public health risk (seven food-handlers and one health-care worker), complete follow-up information was available for only five. Most cases were in overseas-born individuals who may have been infected when returning to their country of birth. Explicit follow-up protocols need to cover appropriate clinical management (including treatment of chronic carriage) and monitoring of those cases and contacts who could pose a public health risk.

Hepatitis A in south-eastern Sydney 1997-1999: continuing concerns for gay men and an outbreak among illicit drug users.

The incidence of hepatitis A virus (HAV) in south-eastern Sydney is one of the highest in Australia with large outbreaks previously associated with male-to-male sexual contact. We report HAV notification trends over the period 1 June 1997 to 31 May 1999 for this location. In the first twelve-month period, 233 cases were notified (crude rate 30.5/100,000 per year) with a peak incidence of 110/100,000 in males aged 20-39 years. Over 60% of male cases reported male-to-male sexual contact. The notification rate (crude rate 15.5/100,000) and proportion of males (61%) was considerably lower in the following twelve month period with 118 cases notified. Less than a third of males reported male-to-male sexual contact. An outbreak (n = 45) of HAV among illicit drug users and their contacts was detected in December 1998. The transmission of HAV remains endemic in south-eastern Sydney. Vaccination among high-risk groups remains an important preventive strategy.

Notification of infectious diseases by general practitioners: a quantitative and qualitative study.

OBJECTIVE: To examine general practitioners' knowledge and practices concerning reporting of notifiable conditions, and to examine barriers to notification of infectious diseases by general practitioners and identify strategies for improving the notification process. DESIGN AND SETTING: Audit of the 100 most recent notifications received by the South Eastern Sydney Public Health Unit of cases of each of hepatitis A, pertussis and measles; and focus groups with GPs practising in Sydney's eastern and southern suburbs, some of whom were selected on the basis of their notification practices. RESULTS: Although these diseases are notifiable on clinical suspicion, only about 40% of the hepatitis A and pertussis cases and 80% of measles cases (54% overall) had been notified by GPs. Delays between doctor and laboratory notifications were an average of seven days for hepatitis A, 19 days for pertussis and seven days for measles. Focus groups showed that at least some GPs have poor understanding of the process of notification, most felt uncomfortable notifying an unconfirmed case, many preferred to leave notification to the laboratory because of concerns about damaging the doctor-patient relationship, and that there is need for financial or other incentives. CONCLUSIONS: There are deficiencies in the completeness and timeliness of notification by GPs which may adversely affect the timing of prophylaxis and outbreak control. Notification by GPs may be improved by such strategies as better notification forms and better feedback to doctors on the outcomes.

Presumptive summer influenza A: an outbreak on a trans-Tasman cruise.

A number of recent reports from the Northern Hemisphere have drawn attention to the occurrence of summer outbreaks (May to August) of influenza A among cruise ship passengers and their contacts. In cases amongst passengers returning to Canada from Alaska, exposure appears to have occurred during the land-based Alaskan tour with illness developing during the subsequent cruise. A late summer outbreak of influenza A among passengers and crew on the return leg of a 14-day Sydney-New Zealand-Sydney cruise is reported in this article.

Unusual cluster of mild invasive serogroup C meningococcal infection in a university college.

The objective of this study was to describe the epidemiology and public health response to an apparent cluster of Neisseria meningitidis serogroup C infection in university students in a residential college. A conventional epidemiological approach was taken, supported by routine and novel diagnostic techniques. Over the two days of 21-22 August 1997, three cases of suspected meningococcal infection were notified from a residential college complex at a university campus in the Sydney metropolitan area. Neisseria meningitidis was grown from throat swabs of all three cases, and was isolated from the blood of one case only. All three isolates were typed as C:2a:P1.5,2. Seroconversion was demonstrated by a novel method in the three cases. Rifampicin was given to all identified contacts. Forty-seven days after the index case, a 19 year old female living in the same complex was diagnosed with bacterial meningitis, and identified contacts given rifampicin. When this isolate was found to be group C, it was decided to vaccinate residents of the college complex. Genotyping and serotyping (C:2a:P1.5) later revealed the fourth isolate to be distinct from isolates from Cases 1-3. In conclusion the authors note that Australia's increasing capacity to type meningococcal strains is essential to understanding the epidemiology of this disease. Furthermore, typing information is of critical importance when decisions are made regarding mass vaccination. As early antibiotic treatment may inhibit isolation of the organism, development of novel approaches to diagnosis and typing should be supported.

Mycobacterial lymphadenitis in eastern Sydney.

BACKGROUND: There has been a resurgence of tuberculosis (TB) in the developed world, especially extrapulmonary manifestations, of which lymphadenitis is the most common. We reviewed all cases of mycobacterial lymphadenitis notified in the eastern suburbs of Sydney from 1989 to 1996. AIMS: To review all cases of mycobacterial adenitis in eastern Sydney. METHODS: This was a retrospective review of the medical records of 54 patients (aged 1.2 to 84 years), recruited from all notifications of TB presenting as lymphadenitis at Prince of Wales, Sydney Children's and St Vincent's Hospitals. RESULTS: There were two distinct groups: Group 1, patients with Mycobacterium tuberculosis (MTB), n = 37 (68.5%), Group 2, patients with atypical mycobacteria, n = 17 (31.5%). For Group 1, 83.3% were foreign born and 18.9% were positive for the human immunodeficiency virus (HIV). Disease involved single node groups in 73% (the cervical chain was involved in 70.1%). Complete resolution of lymphadenopathy at conclusion of treatment occurred in 73.1%. Outcome was not documented in 13.5%, of the rest; 83.8% completed treatment; 2.7% were lost to follow up before treatment concluded; 2.7% were still being seen at the time of writing and 10.8% died within six months of treatment starting (all were HIV positive). HIV positive patients had more diffuse disease. Group 2 were all Australian born. They comprised children less than six years who were all HIV negative and adults (aged 30-55 years) who were all HIV positive. The children were all treated surgically with 80% having complete resolution of their modes. Those adults with HIV had a mortality of 83.3% during treatment. CONCLUSIONS: In eastern Sydney lymphadenitis caused by MTB in the HIV negative population is mostly seen in those who are immigrants. Our large proportion of HIV positive patients tended to have diffuse disease and a high mortality. The reporting of outcomes was poor and in a greater than expected number of outcome and follow up were inadequately documented.