We should not be complacent about our population-based public health response to the first influenza pandemic of the 21st century

Revisiting the Effects of High-Speed Railway Transfers in the Early COVID-19 Cross-Province Transmission in Mainland China

Coronavirus disease 2019 (COVID-19) is an ongoing pandemic that was reported at the end of 2019 in Wuhan, China, and was rapidly disseminated to all provinces in around one month. The study aims to assess the changes in intercity railway passenger transport on the early spatial transmission of COVID-19 in mainland China. Examining the role of railway transport properties in disease transmission could help quantify the spatial spillover effects of large-scale travel restriction interventions. This study used daily high-speed railway schedule data to compare the differences in city-level network properties (destination arrival and transfer service) before and after the Wuhan city lockdown in the early stages of the spatial transmission of COVID-19 in mainland China. Bayesian multivariate regression was used to examine the association between structural changes in the railway origin-destination network and the incidence of COVID-19 cases. Our results show that the provinces with rising transfer activities after the Wuhan city lockdown had more confirmed COVID-19 cases, but changes in destination arrival did not have significant effects. The regions with increasing transfer activities were located in provinces neighboring Hubei in the widthwise and longitudinal directions. These results indicate that transfer activities enhance interpersonal transmission probability and could be a crucial risk factor for increasing epidemic severity after the Wuhan city lockdown. The destinations of railway passengers might not be affected by the Wuhan city lockdown, but their itinerary routes could be changed due to the replacement of an important transfer hub (Wuhan city) in the Chinese railway transportation network. As a result, transfer services in the high-speed rail network could explain why the provinces surrounded by Hubei had a higher number of confirmed COVID-19 cases than other provinces.

Ten Years of National Seasonal Surveillance for Severe Complications of Influenza in Australian Children

BACKGROUND

Severe complications of influenza in children are uncommon but may result in admission to hospital or an intensive care unit (ICU) and death.

METHODS

Active prospective surveillance using the Australian Paediatric Surveillance Unit with monthly reporting by pediatricians of national demographic and clinical data on children with <15 years of age hospitalized with severe complications of laboratory-confirmed influenza during ten influenza seasons 2008-2017.

RESULTS

Of 722 children notified, 613 had laboratory-confirmed influenza and at least one severe complication. Most (60%) were <5 years of age; 10% were <6 months, hence ineligible for vaccination. Almost half of all cases were admitted to ICU and 30 died. Most children were previously healthy: 40.3% had at least one underlying medical condition. Sixty-five different severe complications were reported; pneumonia was the most common, occurring in over half of all cases. Influenza A accounted for 68.6% hospitalizations; however, influenza B was more often associated with acute renal failure (P = 0.014), rhabdomyolysis (P = 0.019), myocarditis (P = 0.015), pericarditis (P = 0.013), and cardiomyopathy (P = 0.035). Children who died were more likely to be older (5-14 years), have underlying medical conditions, be admitted to ICU, and have encephalitis, acute renal failure, or myocarditis. Only 36.1% of all children reported received antiviral medications, and 8.5% were known to be vaccinated for seasonal influenza.

CONCLUSIONS

Severe influenza complications cause morbidity and mortality in children, which may increase if coinfection with COVID-19 occurs in the 2020 season and beyond. Increased vaccination rates, even in healthy children, early diagnosis and timely antiviral treatment are needed to reduce severe complications and death.

Entry screening for infectious diseases in humans

In response to the severe acute respiratory syndrome (SARS) pandemic of 2003 and the influenza pandemic of 2009, many countries instituted border measures as a means of stopping or slowing the spread of disease. The measures, usually consisting of a combination of border entry/exit screening, quarantine, isolation, and communications, were resource intensive, and modeling and observational studies indicate that border screening is not effective at detecting infectious persons. Moreover, border screening has high opportunity costs, financially and in terms of the use of scarce public health staff resources during a time of high need. We discuss the border-screening experiences with SARS and influenza and propose an approach to decision-making for future pandemics. We conclude that outbreak-associated communications for travelers at border entry points, together with effective communication with clinicians and more effective disease control measures in the community, may be a more effective approach to the international control of communicable diseases.

Evidence compendium and advice on social distancing and other related measures for response to an influenza pandemic

The role of social distancing measures in mitigating pandemic influenza is not precisely understood. To this end, we have conducted a systematised review, particularly in light of the 2009 pandemic influenza, to better inform the role of social distancing measures against pandemic influenza. Articles were identified from relevant databases and the data were synthesised to provide evidence on the role of school or work place-based interventions, case-based distancing (self-isolation, quarantine), and restriction of mobility and mass gatherings. School closure, whether proactive or reactive, appears to be moderately effective and acceptable in reducing the transmission of influenza and in delaying the peak of an epidemic but is associated with very high secondary costs. Voluntary home isolation and quarantine are also effective and acceptable measures but there is an increased risk of intra-household transmission from index cases to contacts. Work place-related interventions like work closure and home working are also modestly effective and are acceptable, but likely to be economically disruptive. Internal mobility restriction is effective only if prohibitively high (50% of travel) restrictions are applied and mass gatherings occurring within 10 days before the epidemic peak are likely to increase the risk of transmission of influenza.

Airport arrivals screening during pandemic (H1N1) 2009 influenza in New South Wales, Australia

OBJECTIVE

To examine the effectiveness of airport screening in New South Wales during pandemic (H1N1) 2009 influenza.

DESIGN, SETTING AND PARTICIPANTS

Analysis of data collected at clinics held at Sydney Airport, and of all notified cases of influenza A(H1N1)pdm09, between 28 April 2009 and 18 June 2009.

MAIN OUTCOME MEASURES

Case detection rate per 100,000 passengers screened, sensitivity, positive predictive value and specificity of airport screening. The proportion of all cases in the period detected at airport clinics was compared with the proportion detected in emergency departments and general practice.

RESULTS

Of an estimated 625,147 passenger arrivals at Sydney Airport during the period, 5845 (0.93%) were identified as being symptomatic or febrile, and three of 5845 were subsequently confirmed to have influenza A(H1N1)pdm09, resulting in a detection rate of 0.05 per 10,000 screened (95% CI, 0.02-1.14 per 10,000). Forty-five patients with overseas-acquired influenza A(H1N1)pdm09 in NSW would have probably passed through the airport during this time, giving airport screening a sensitivity of 6.67% (95% CI, 1.40%-18.27%). Positive predictive value was 0.05% (95% CI, 0.02%-0.15%) and specificity 99.10% (95% CI, 99.00%-100.00%). Of the 557 confirmed cases across NSW during the period, 290 (52.1%) were detected at emergency departments and 135 (24.2%) at general practices, compared with three (0.5%) detected at the airport.

CONCLUSIONS

Airport screening was ineffective in detecting cases of influenza A(H1N1)pdm09 in NSW. Its future use should be carefully considered against potentially more effective interventions, such as contact tracing in the community.

Are we prepared to help low-resource communities cope with a severe influenza pandemic?

Recent research involving lab-modified H5N1 influenza viruses with increased transmissibility and the ongoing evolution of the virus in nature should remind us of the continuing importance of preparedness for a severe influenza pandemic. Current vaccine technology and antiviral supply remain inadequate, and in a severe pandemic, most low-resource communities will fail to receive adequate medical supplies. However, with suitable guidance, these communities can take appropriate actions without substantial outside resources to reduce influenza transmission and care for the ill. Such guidance should be completed, and support provided to developing countries to adapt it for their settings and prepare for implementation.

A model for the emergence of drug resistance in the presence of asymptomatic infections

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We model the emergence of drug resistance in the presence of asymptomatic cases.

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The absence of a preclinical state leads to an overestimation of peak incidence.

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Two reproduction numbers, for drug sensitive or resistant strains, are identified.

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Drug resistant and sensitive strains can coexist in the population.

An analysis of a mathematical model, which describes the dynamics of an aerially transmitted disease, and the effects of the emergence of drug resistance after the introduction of treatment as an intervention strategy is presented. Under explicit consideration of asymptomatic and symptomatic infective individuals for the basic model without intervention the analysis shows that the dynamics of the epidemic is determined by a basic reproduction number R0. A disease-free and an endemic equilibrium exist and are locally asymptotically stable when R0<1 and R0>1 respectively. When treatment is included the system has a basic reproduction number, which is the largest of the two reproduction numbers that characterise the drug-sensitive (R1) or resistant (R2) strains of the infectious agent. The system has a disease-free equilibrium, which is stable when both R1 and R2 are less than unity. Two endemic equilibria also exist and are associated with treatment and the development of drug resistance. An endemic equilibrium where only the drug-resistant strain persists exists and is stable when R2>1 and R1<R2. A second endemic equilibrium exists when R1>1 and R1>R2 and both drug-sensitive and drug-resistant strains are present. The analysis of the system provides insights about the conditions under which the infection will persist and whether sensitive and resistant strains will coexist or not.

Aerosol susceptibility of influenza virus to UV-C light

The person-to-person transmission of influenza virus, especially in the event of a pandemic caused by a highly virulent strain of influenza, such as H5N1 avian influenza, is of great concern due to widespread mortality and morbidity. The consequences of seasonal influenza are also substantial. Because airborne transmission appears to play a role in the spread of influenza, public health interventions should focus on preventing or interrupting this process. Air disinfection via upper-room 254-nm germicidal UV (UV-C) light in public buildings may be able to reduce influenza transmission via the airborne route. We characterized the susceptibility of influenza A virus (H1N1, PR-8) aerosols to UV-C light using a benchtop chamber equipped with a UVC exposure window. We evaluated virus susceptibility to UV-C doses ranging from 4 to 12 J/m(2) at three relative humidity levels (25, 50, and 75%). Our data show that the Z values (susceptibility factors) were higher (more susceptible) to UV-C than what has been reported previously. Furthermore, dose-response plots showed that influenza virus susceptibility increases with decreasing relative humidity. This work provides an essential scientific basis for designing and utilizing effective upper-room UV-C light installations for the prevention of the airborne transmission of influenza by characterizing its susceptibility to UV-C.