[Cost-effectiveness analysis of quadrivalent influenza vaccination for older adults aged 60 and above in mainland China].

Objective: To evaluate the cost-effectiveness of government fully-funded quadrivalent influenza vaccination (QIV) program for older adults aged 60 and above in mainland China. Methods: Based on decision tree model in the previous research on the cost-effectiveness analysis of TIV immunization, we extended the structure of model and updated the key parameters such as influenza patients' healthcare seeking behavior, vaccine cost, vaccine coverage and vaccine efficacy/effectiveness to estimate influenza-associated outpatient consultations, hospitalizations, respiratory disease excess mortality and quality-adjusted life years (QALY) between the QIV and no vaccination or TIV program. And incremental cost and incremental cost-effectiveness ratio (ICER) were evaluated between the QIV and no vaccination or TIV program from the societal perspective. The time frame of the study is one year. All costs were adjusted to 2019 using the consumer price index. Results: Comparing the fully-funded QIV and no vaccination or TIV for older adults aged 60 and above is separately expected to prevent 45 070 or 2 718 influenza-associated influenza-like illness (ILI) outpatients, 21 451 or 1 294 influenza-associated severe acute respiratory infection (SARI) hospitalizations, 19 346 or 1 167 influenza-associated respiratory excess deaths and avoid 155 234 or 9 363 QALY loss each year. Compared with no vaccination, introducing QIV into National Immunization Program (NIP) is expected to increase the cost of 11.71 billion yuan from the societal perspective. The incremental cost per QALY gained between QIV and no vaccination was 75 325 yuan per QALY, which is higher than willingness-to-pay (WTP) threshold (one-fold gross domestic product per capita is considered as WTP: 70 892 yuan) and means no cost effective. Introducing QIV rather than TIV into NIP will cost 7.98 billion yuan from the societal perspective and the ICER was 852.54 thousand yuan per QALY which is much higher than WTP and means no cost effective as well. The threshold of vaccination cost between QIV and no vaccination or TIV should no more than 113.41 or 6.83 yuan when the two comparators' scenarios above are all cost effective. Conclusion: Under the condition of current vaccine effectiveness and vaccine cost, comparing fully-funded QIV with no or TIV vaccination program is not cost effective for people aged 60 years or older.

[Estimating the disease burden of seasonal influenza in China, 2006-2019].

Objective: To estimate the health impact and economic burden of seasonal influenza in mainland China. Methods: From systematic literature reviews, we collected the influenza-associated excess influenza-like-illness (ILI) outpatient consultation rates, hospitalization rates of severe acute respiratory infections (SARI) and respiratory excess mortality, 2006-2017. Using these data, as well as demographic data (2019), the number of influenza-associated excess ILI outpatient consultations, SARI hospitalizations and respiratory excess deaths were estimated. Then using per capita economic burden of influenza-associated outpatient consultations and hospitalizations, as well as the productivity loss of influenza-related premature deaths, the annual influenza-associated total economic burden was estimated. All costs were adjusted to 2019 using the consumer price index. Results: The annual influenza-associated excess ILI outpatient consultations, SARI hospitalizations and excess respiratory deaths were 3 million, 2.34 million, 0.09 million, respectively. The total economic burden was 26.38 billion CNY, accounting for 0.266‰ GDP in 2019, of which the hospitalization-related economic burden accounted for the highest proportion (86.4%, 22.79 billion CNY), followed by the outpatient-related economic burden (11.3%, 2.97 billion CNY), and the indirect economic burden of productivity loss of premature deaths was the lowest (2.4%, 0.62 billion CNY). Largest economic burden was observed in East China (10.51 billion CNY) and smallest observed in Northeast China (0.38 billion CNY). Conclusion: The health burden of influenza-related outpatient visits and hospitalizations were substantial. The economic burden of influenza-related SARI hospitalization was higher than that of influenza-related outpatients and pre-mature deaths. The highest economic burden of influenza occurred in the East China.

Risk assessment of recent Egyptian H5N1 influenza viruses.

Highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype are enzootic in poultry populations in different parts of the world, and have caused numerous human infections in recent years, particularly in Egypt. However, no sustained human-to-human transmission of these viruses has yet been reported. We tested nine naturally occurring Egyptian H5N1 viruses (isolated in 2014-2015) in ferrets and found that three of them transmitted via respiratory droplets, causing a fatal infection in one of the exposed animals. All isolates were sensitive to neuraminidase inhibitors. However, these viruses were not transmitted via respiratory droplets in three additional transmission experiments in ferrets. Currently, we do not know if the efficiency of transmission is very low or if subtle differences in experimental parameters contributed to these inconsistent results. Nonetheless, our findings heighten concern regarding the pandemic potential of recent Egyptian H5N1 influenza viruses.

Sensitivities of biomechanical assessment methods for fracture healing of long bones.

There is a controversy as to whether the biomechanical methods are feasible to assess fracture healing of long bones. This paper investigated the sensitivities of two biomechanical methods, torsion and bending, for assessing fracture healing of long bones; both a simplified beam model and finite element model of an artificial femur were employed. The results demonstrated that, in the initial healing stage, the whole-bone stiffness of the fractured bone is extremely sensitive to the variation of the callus stiffness at the fracture site; when the shear (or Young's) modulus of the callus reaches 15% that of the intact bone, the whole-bone stiffness rises up to 90% that of the intact bone. After that, the whole-bone torsional (or bending) stiffness increases slowly; it becomes less sensitive to the variation of the callus stiffness. These results imply that the whole-bone stiffness is of limited reliability to assess the healing quality particular at late stages of the healing process. The simplified model in this paper provided a theoretical framework to explain why the whole-bone stiffness is insensitive to the healing process of fractured long bones in the late stage of healing. The conclusions obtained from the simplified model were verified with the finite element simulations of the artificial femur.

Monte Carlo simulation of a Bonner sphere spectrometer for application to the determination of neutron field in the Experimental Advanced Superconducting Tokamak experimental hall.

To assess the neutron energy spectra and the neutron dose for different positions around the Experimental Advanced Superconducting Tokamak (EAST) device, a Bonner Sphere Spectrometer (BSS) was developed at Peking University, with totally nine polyethylene spheres and a SP9 (3)He counter. The response functions of the BSS were calculated by the Monte Carlo codes MCNP and GEANT4 with dedicated models, and good agreement was found between these two codes. A feasibility study was carried out with a simulated neutron energy spectrum around EAST, and the simulated "experimental" result of each sphere was obtained by calculating the response with MCNP, which used the simulated neutron energy spectrum as the input spectrum. With the deconvolution of the "experimental" measurement, the neutron energy spectrum was retrieved and compared with the preset one. Good consistence was found which offers confidence for the application of the BSS system for dose and spectrum measurements around a fusion device.

Biomechanical assessment of a novel L4/5 level interspinous implant using three dimensional finite element analysis.

OBJECTIVES: Range of motion (ROM) is often restricted by conventional spinal fusion surgery, while some complications also occurred after applying posterior dynamic devices in clinic. Therefore, new surgical implant options were necessitated. The biomechanical features of a novel interspinous implant were investigated using three dimensional (3D) finite element models (FEMs). MATERIALS AND METHODS: An "H-shaped" polyether ether ketone (PEEK) interspinous implant was designed to tightly fit the upper and lower spinous processes, featuring a hollow cylindrical portion which was implanted autologous bones to enhance fusion with spinous processes. A 3D FEM of the intact L3/S segment with mild disc degeneration in L4/5 (degenerated model) was developed and subjected to flexion-extension, lateral bending, and axial rotation either with or without the implanted prosthesis (implant model) in order to examine effects on ROM, intradiscal stress, and facet joint load. RESULTS: The whole lumbar ROM was altered slightly by implant insertion, and reduced end plate stress, nucleus stress, and facet joints load at the L4/5 level (implant location) were observed. L4/5 flexion-extension maximal end plate stress, nucleus stress, and facet joints load were 5.262 MPa, 0.1648 MPa, and 29.7 N, respectively, in the degenerated model and 2.323 MPa, 0.0892 MPa, and 5.4 N, respectively, in the implant model. End plate and nucleus stresses were partially alleviated at the L3/4 level. Slightly higher maximal von Mises stress in L3/4 and L5/S annuli were observed in the implant model. CONCLUSIONS: The proposed novel interspinous implant effectively restored stability without producing excessive ROM limitations, meriting further clinical evaluation. Furthermore, these findings provide a useful basis for wide application of FEM in a broad variety of spinal implant assessments.

The advantages of mosquito biocontrol by stocking edible fish in rice paddies.

Edible fish stocked in rice fields at a density of 600-800 fry per mu (1 mu = 1/15 hectare) for 150-170 days may act as an effective mosquito biocontrol agent. Common carp (Cyprinus carpio), grass carp Ctenopharyngodon idella) and Tilopia spp. killed late stage larvae and pupae of Anopheles sinensis and Culex tritaeniorrhyncus in laboratory and field trials. Stocking of fish in experimental rice fields decreased larval numbers significantly in comparison with control areas. Expansion of fish stocking in rice fields on a large scale over several years correlated with a marked decrease in malaria transmission. The addition of fish to the rice fields also resulted in increased yields. A ditch-ridge system of field arrangements is described for optimization of fish handling. Preliminary cost-benefit analysis indicates that this approach to mosquito control conveys considerable economic advantage and thus provides incentive to the community to participate in vector control programs. Farmers' experience in Guangxi over a number of years indicates that the use of edible fish for this purpose can be carried on a large, commercially viable scale.