Risk of COVID-19 importation to the Pacific islands through global air travel.

On 30 January 2020, WHO declared coronavirus (COVID-19) a global public health emergency. As of 12 March 2020, 125 048 confirmed COVID-19 cases in 118 countries had been reported. On 12 March 2020, the first case in the Pacific islands was reported in French Polynesia; no other Pacific island country or territory has reported cases. The purpose of our analysis is to show how travellers may introduce COVID-19 into the Pacific islands and discuss the role robust health systems play in protecting health and reducing transmission risk. We analyse travel and Global Health Security Index data using a scoring tool to produce quantitative estimates of COVID-19 importation risk, by departing and arriving country. Our analysis indicates that, as of 12 March 2020, the highest risk air routes by which COVID-19 may be imported into the Pacific islands are from east Asian countries (specifically, China, Korea and Japan) to north Pacific airports (likely Guam, Commonwealth of the Northern Mariana Islands or, to a less extent, Palau); or from China, Japan, Singapore, the United States of America or France to south Pacific ports (likely, Fiji, Papua New Guinea, French Polynesia or New Caledonia). Other importation routes include from other east Asian countries to Guam, and from Australia, New Zealand and other European countries to the south Pacific. The tool provides a useful method for assessing COVID-19 importation risk and may be useful in other settings.

The contribution of travellers visiting friends and relatives to notified infectious diseases in Australia: state-based enhanced surveillance.

Immigrants and their children who return to their country of origin to visit friends and relatives (VFR) are at increased risk of acquiring infectious diseases compared to other travellers. VFR travel is an important disease control issue, as one quarter of Australia's population are foreign-born and one quarter of departing Australian international travellers are visiting friends and relatives. We conducted a 1-year prospective enhanced surveillance study in New South Wales and Victoria, Australia to determine the contribution of VFR travel to notifiable diseases associated with travel, including typhoid, paratyphoid, measles, hepatitis A, hepatitis E, malaria and chikungunya. Additional data on characteristics of international travel were collected. Recent international travel was reported by 180/222 (81%) enhanced surveillance cases, including all malaria, chikungunya and paratyphoid cases. The majority of cases who acquired infections during travel were immigrant Australians (96, 53%) or their Australian-born children (43, 24%). VFR travel was reported by 117 (65%) travel-associated cases, highest for typhoid (31/32, 97%). Cases of children (aged <18 years) (86%) were more frequently VFR travellers compared to adult travellers (57%, P < 0·001). VFR travel is an important contributor to imported disease in Australia. Communicable disease control strategies targeting these travellers, such as targeted health promotion, are likely to impact importation of these travel-related infections.

Risk factors for herpes zoster in a large cohort of unvaccinated older adults: a prospective cohort study.

We analysed data from a prospective cohort of 255,024 adults aged ⩾45 years recruited from 2006-2009 to identify characteristics associated with a zoster diagnosis. Diagnoses were identified by linkage to pharmaceutical treatment and hospitalization records specific for zoster and hazard ratios were estimated. Over 940,583 person-years, 7771 participants had a zoster diagnosis; 253 (3·3%) were hospitalized. After adjusting for age and other factors, characteristics associated with zoster diagnoses included: having a recent immunosuppressive condition [adjusted hazard ratio (aHR) 1·58, 95% confidence interval (CI) 1·32-1·88], female sex (aHR 1·36, 95% CI 1·30-1·43), recent cancer diagnosis (aHR 1·35, 95% CI 1·24-1·46), and severe physical limitation vs. none (aHR 1·33, 95% CI 1·23-1·43). The relative risk of hospitalization for zoster was higher for those with an immunosuppressive condition (aHR 3·78, 95% CI 2·18-6·55), those with cancer (aHR 1·78, 95% CI 1·24-2·56) or with severe physical limitations (aHR 2·50, 95% CI 1·56-4·01). The novel finding of an increased risk of zoster diagnoses and hospitalizations in those with physical limitations should prompt evaluation of the use of zoster vaccine in this population.

Australian Hajj pilgrims' knowledge, attitude and perception about Ebola, November 2014 to February 2015.

Upon return from Hajj 2014, 150 Australian pilgrims were interviewed about their understanding of the Ebola epidemic. Most (89%, 134/150) knew of the epidemic before travelling and 60% (80/134) of those knew Ebola transmits through body fluids. Pilgrims who received pre-travel health advice were more conscious of Ebola (69% vs 31%, p = 0.01) and adhered better to hand hygiene after touching an ill person (68% vs 31%, p < 0.01). Mass media was the main information source (78%).

A Meta-Analysis of the Prevalence of Influenza A H5N1 and H7N9 Infection in Birds.

Despite a much higher rate of human influenza A (H7N9) infection compared to influenza A (H5N1), and the assumption that birds are the source of human infection, detection rates of H7N9 in birds are lower than those of H5N1. This raises a question about the role of birds in the spread and transmission of H7N9 to humans. We conducted a meta-analysis of overall prevalence of H5N1 and H7N9 in different bird populations (domestic poultry, wild birds) and different environments (live bird markets, commercial poultry farms, wild habitats). The electronic database, Scopus, was searched for published papers, and Google was searched for country surveillance reports. A random effect meta-analysis model was used to produce pooled estimates of the prevalence of H5N1 and H7N9 for various subcategories. A random effects logistic regression model was used to compare prevalence rates between H5N1 and H7N9. Both viruses have low prevalence across all bird populations. Significant differences in prevalence rates were observed in domestic birds, farm settings, for pathogen and antibody testing, and during routine surveillance. Random effects logistic regression analyses show that among domestic birds, the prevalence of H5N1 is 47.48 (95% CI: 17.15-133.13, P < 0.001) times higher than H7N9. In routine surveillance (where surveillance was not conducted in response to human infections or bird outbreaks), the prevalence of H5N1 is still higher than H7N9 with an OR of 43.02 (95% CI: 16.60-111.53, P < 0.001). H7N9 in humans has occurred at a rate approximately four times higher than H5N1, and for both infections, birds are postulated to be the source. Much lower rates of H7N9 in birds compared to H5N1 raise doubts about birds as the sole source of high rates of human H7N9 infection. Other sources of transmission of H7N9 need to be considered and explored.

The role of travel in measles outbreaks in Australia - An enhanced surveillance study.

Many developed countries, like Australia, maintain a high population level immunity against measles, however, there remains a risk of acquisition of measles in non-immune travellers and subsequent importation into Australia leading to localised outbreaks. In this study, we estimate the incidence of measles and describe characteristics including immunisation and pre-travel health seeking behaviour of notified cases of measles in New South Wales and Victoria, Australia between February 2013 and January 2014. Cases were followed up by telephone interview using a questionnaire to collect information of demographic and travel characteristics. In NSW, the incidence was highest in age group 0-9years (20/million population) whereas in Victoria the highest incidence was observed in 10-19 (23/million population) years group. Out of 44 cases interviewed, 25 (56.8%) had history of travel outside of Australia during or immediately prior to the onset of measles. Holiday (60%) was the main reason for travel with 44% (11/25) reporting visiting friends and relatives (VFR) during the trip. The major reason described for not seeking prior medical advice before travel were "no perceived risk of diseases" (41%) and "previous overseas travel without any problem" (41%). Of the 25 measles cases with recent overseas travel during the incubation period, one reported a measles vaccine prior to their recent trip. Four cases were children of parents who refused vaccination. Twenty out of 25 (80.0%) had attended mass gathering events. Young adults and VFR travellers should be a high priority for preventive strategies in order to maintain measles elimination status.

Vaccinations against respiratory tract infections at Hajj.

The transmission of respiratory tract infections (RTIs) is very high among the Hajj congregation in Mecca, Saudi Arabia. Despite recommendations for vaccinations, pilgrims remain at increased risk of RTIs. In this paper we systematically reviewed available studies assessing the uptake and effectiveness of vaccinations against RTIs among Hajj pilgrims and enumerated important demographic factors, if described, associated with vaccine uptake. Of the 42 included studies, 29 reported on the uptake and effectiveness of influenza vaccine among pilgrims, eight studies reported the uptake of other vaccines, notably pneumococcal, diphtheria and bacillus Calmette-Guérin vaccines, and the remaining five studies described both influenza and non-influenza vaccines. The uptake of seasonal influenza vaccine ranged from 0.7% to 100% across the study populations, with coverage highest in the elderly and those with pre-existing co-morbidities. The effectiveness of influenza vaccine was variable across studies but was significantly effective against laboratory-confirmed influenza (risk ratio 0.56; 95% CI 0.41-0.75; p <0.001) in pooled metadata from six studies. Uptake of diphtheria and pneumococcal vaccines was low, and the only study reporting pertussis among Hajj pilgrims found the presence of pre-Hajj immunity to be significantly protective against disease. Despite favourable evidence of effectiveness, our review shows variable uptake of vaccines across a number of studies with few data available on the uptake of non-influenza vaccines. Mixed-method studies are needed to gauge knowledge, attitudes and practices of Hajj pilgrims regarding vaccination, and randomized controlled trials are required to confirm the efficacy of vaccines and improve uptake in this vulnerable travelling population.

Changes in seroprevalence to hepatitis A in Victoria, Australia: a comparison of three time points.

Serological data provide an important measure of past exposure and immunity to hepatitis A virus (HAV) infection in a population. National serosurveys from developed countries have typically indicated a decline in HAV seroprevalence over time as sanitation levels improve. We examined trends in the seroepidemiology of HAV antibodies in Victoria, Australia, drawing on cross-sectional samples taken at three time points over a 20-year period. Stored sera from 1988 (n=753), 1998 (n=1091), and 2008 (n=791) from persons aged 1-69 years were obtained from the state of Victoria, Australia. The within-year population adjusted results show a significant trend of increasing population HAV seroprevalence over time from 34.3% (95% CI 31.7-36.9) in 1988, to 40.0% (95% CI 37.1-42.8) in 1998 and 55.1% (95% CI 52.1-58.1) in 2008, P<0.0001. A particularly noticeable rise in population seroprevalence was observed between 1998 and 2008 for those aged 5-39 years. The increase in HAV seropositivity over time is in contrast to the declining rates of disease notification in Australia. Based on comparisons with other Australian data, it appears the increase in population seroprevalence over the last two decades is unlikely to be due to endemic transmission of infection. Instead, other factors, including increases in travel to HAV endemic regions, migration to Australia from HAV endemic regions and vaccine uptake are more likely causes. Ongoing monitoring of serological HAV profiles in the population is required to determine future policy direction to prevent increased burden.