scholarly journals Design of Vaccine Trials during Outbreaks with and without a Delayed Vaccination Comparator

2016 ◽  
Author(s):  
Natalie E. Dean ◽  
M. Elizabeth Halloran ◽  
Ira M. Longini
Keyword(s):  
Immune Response ◽  
Incubation Period ◽  
Vaccine Efficacy ◽  
Emerging Pathogens ◽  
Illness Onset ◽  
Efficacy Trials ◽  
Randomized Design ◽  
Time Of Infection ◽  
Cluster Randomized ◽  
Time Required

AbstractConducting vaccine efficacy trials during outbreaks of emerging pathogens poses particular challenges. The ‘Ebola ça suffit’ trial in Guinea used a novel ring vaccination cluster randomized design to target populations at highest risk of infection. Another key feature of the trial was the use of a delayed vaccination arm as a comparator, in which clusters were randomized to immediate vaccination or vaccination 21 days later. This approach, chosen to improve ethical acceptability of the trial, complicates the statistical analysis as participants in the comparison arm are eventually protected by vaccine. Furthermore, for infectious diseases, we observe time of illness onset and not time of infection, and we may not know the time required for the vaccinee to develop a protective immune response. As a result, including events observed shortly after vaccination may bias the per protocol estimate of vaccine efficacy. We provide a framework for approximating the bias and power of any given per protocol analysis period as functions of the background infection hazard rate, disease incubation period, and vaccine immune response. We use this framework to provide recommendations for designing standard vaccine efficacy trials and trials with a delayed vaccination comparator. Briefly, narrower analysis periods within the correct window can minimize or eliminate bias but may suffer from reduced power. Designs should be reasonably robust to misspecification of the incubation period and time to develop a vaccine immune response.

The The Effect of Level Farmers' Knowledge In Some Active Chemical Insecticides Resistance to Control Plutella Xylostella Scale Laboratory

1970 ◽  
Vol 2 (1) ◽  
pp. 22-32
Author(s):  
Rasiska Tarin
Keyword(s):  
Active Ingredient ◽  
Plutella Xylostella ◽  
Plant Diseases ◽  
Chemical Insecticide ◽  
Randomized Design ◽  
Active Chemical ◽  
Questionnaire Result ◽  
Completely Randomized Design ◽  
Time Required ◽  
Two Stages

Pengaruh Tingkat Pengetahuan Petani  Pada Resistensi Beberapa Bahan Aktif Insektisida Kimia Untuk Mengendalikan Ulat Plutella Xylostella Skala Laboratorium The Effect of Level Farmers' Knowledge In Some  Active Chemical Insecticides Resistance to Control Plutella Xylostella Scale Laboratory Catur Hermanto, Rasiska Tarigan dan Fatiani Manik Balai Penelitian Tanaman Sayuran – Badan Penelitian dan Pengembangan Pertanian Jln Tangkuban Perahu No 517, Lembang, Bandung Barat 40391; e-mail: [email protected]   ABSTRAK  Petani dan pestisida merupakan dua sisi  yang saling berkaitan dalam mengendalikan serangan hama penyakit tanaman dilapangan Penggunaan pestisida oleh petani semakin hari kian meningkat khususnya didataran tinggi, namun  peningkatan ini tidak diimbangi dengan pemahaman dalam menggunakan pestisida. Penelitian ini bertujuan untuk mengetahui  pengaruh tingkat pengetahuan dan resistensi insektisida yang digunakan petani kubis di kabupaten Karo. Penelitian dilaksanakan di laboratorium Kebun Percobaan Berastagi dengan ketinggian tempat 1.340 mdpl yang dilaksanakan dari bulan september sampai november 2015. Pelaksanaan dibagi 2(dua) tahap. Tahap Pertama mengumpulkan makalah melalui teknik diskusi kelompok petani dan pengencer dan wawancara menggunakan kuisioner. Total jumlah responden 10 orang per 4 kecamatana. Dari hasil kuisioner dipilih jenis insektisida yang sering digunakan petani untuk diuji kepekaan ulat plutella xylostella terhadap insektisida yang diuji pada skala dilaboratoium.  Empat perlakuan dengan masing-masing terdiri atas 9 taraf konsentrasi menggunakan rancangan acak lengkap dan diulang 3 kali. Hasil penelitian menunjukkan  petani kubis dikabupaten karo melakukan pencampuran fungi dan insektisida > 2jenis dengan frekwensi penyemprotan 2 x 1 minggum serta dosis yang digunakan tidak sesuai dengan KF yang dianjurkan. Nilai LC 50 insektisida kimia dari bahan aktif klorantranilipro, prefenofos, sipemetrin dan kloropinofos berturut-turut 1,87 ml, 1,5 ml, 1,5 ml dan 2 ml. Dan waktu Waktu yang dibutuhkan untuk mematikan 50 % plutella xylostella (LT 50) dari keempat insektisida kimia berbahan aktif klorantranilipro, prefenofos, sipemetrin dan Kloropinfos berturut-turut adalah  39.20, 19.43, 23.57 dan 30.15 jam Kata kunci : Pengetahuan, Resistensi, Insektisida Kimia, Plutella xylostella , Laboratorium ABSTRACT. The Farmers and pesticides are important aspects that  interrelated tocontroll pests in the field of plant diseases as well as opportunities occur resistensi. The use of pesticides by farmers is constantly increasing, especially in the highlands, but this increase is not offset by an understanding in the use of pesticides. The aimed of the research to find the knowledge and the use of insecticide resistance cabbage farmers in Karo District.   The research was conducted at the laboratory of Berastagi experimental farm with altitude of 1,340 meters above sea level implemented from the month of September to November 2015. The implementation of divided by 2 (two) stages. The first is to collect  issues by discussion technique of farmers group and diluent and interview using a questionnaire. Total number of respondents  is ten peoples each four districts. From the questionnaire result so the selected types of insecticides often used by famers for the testing of  sensitivity plutella xylostella to insecticides test at laboratory scale with four treatment. each consisting of 9 degree of concentration using a completely randomized design and repeated 3 times. each consisting of 9 degree of concentration using a completely randomized design and repeated 3 times. The results showed cabbage farmers in the county karo mixing fungi and insecticides> 2 types with spraying frequency of 2 x 1 week as well as the doses used did not correspond to the recommended KF. LC 50 value of the chemical insecticide active ingredient klorantranilipro, prefenofos, sipemetrin and kloropinofos successively 1.87 ml, 1.5 ml, 1.5 ml and 2 ml. Time and time required to shut down 50% of Plutella xylostella (LT 50) of the four chemical insecticide active ingredient klorantranilipro, prefenofos, sipemetrin and Kloropinfos are respectively 39.20, 19:43, 23:57 and 30.15 hours

scholarly journals Assessing Interventions against Coronavirus Disease 2019 (COVID-19) in Osaka, Japan: A Modeling Study

2021 ◽  
Vol 10 (6) ◽  
pp. 1256
Author(s):  
Ko Nakajo ◽  
Hiroshi Nishiura
Keyword(s):  
Model Comparison ◽  
Reproduction Number ◽  
State Of Emergency ◽  
Illness Onset ◽  
Epidemic Dynamics ◽  
Osaka Prefecture ◽  
Time Of Infection ◽  
Single Intervention ◽  
Second Wave ◽  
Combined Interventions

Estimation of the effective reproduction number, R(t), of coronavirus disease (COVID-19) in real-time is a continuing challenge. R(t) reflects the epidemic dynamics based on readily available illness onset data, and is useful for the planning and implementation of public health and social measures. In the present study, we proposed a method for computing the R(t) of COVID-19, and applied this method to the epidemic in Osaka prefecture from February to September 2020. We estimated R(t) as a function of the time of infection using the date of illness onset. The epidemic in Osaka came under control around 2 April during the first wave, and 26 July during the second wave. R(t) did not decline drastically following any single intervention. However, when multiple interventions were combined, the relative reductions in R(t) during the first and second waves were 70% and 51%, respectively. Although the second wave was brought under control without declaring a state of emergency, our model comparison indicated that relying on a single intervention would not be sufficient to reduce R(t) < 1. The outcome of the COVID-19 pandemic continues to rely on political leadership to swiftly design and implement combined interventions capable of broadly and appropriately reducing contacts.

The development of schistosomiasis mansoni in an immunologically naive immigrant population in Masongaleni, Kenya

Parasitology ◽  
1998 ◽  
Vol 117 (2) ◽  
pp. 123-132 ◽  
Author(s):  
J. H. OUMA ◽  
A. J. C. FULFORD ◽  
H. C. KARIUKI ◽  
G. KIMANI ◽  
R. F. STURROCK ◽  
...  
Keyword(s):  
Immune Response ◽  
Longitudinal Studies ◽  
Endemic Area ◽  
Water Contact ◽  
Immunological Responses ◽  
Schistosomiasis Mansoni ◽  
Age Dependent ◽  
Duration Of Infection ◽  
Per Se ◽  
Time Required

The relocation of several thousand members of the Kamba tribe from the Kyulu Hills to the Thange valley near Masongaleni in Kenya provides an excellent opportunity to study the development of the immune response to schistosomiasis mansoni in a population with little or no previous experience of the infection. An adjacent, well-established Kamba community with similar patterns of water contact provides a suitable endemic control population. The immigrants were, uniquely, examined shortly after their arrival in the endemic area, while the prevalence of infection was still low. At this time faecal egg counts peaked atypically around 30 years of age. Over the next 12–18 months infection increased rapidly, especially among teenagers, producing a pattern of infection more typical of endemic communities. This substantially narrows estimates of the time required to develop the important determinants of the age–intensity profile, supporting the notion that changes related to age per se, rather than duration of infection, dominate. Age-dependent factors might include behaviour or physiology, including immune response. This paper provides the background for continuing longitudinal studies on the development of immunological responses to this parasite.

Twenty Years of Outpatient Respiratory Syncytial Virus Infection: A Framework for Vaccine Efficacy Trials

PEDIATRICS ◽  
1997 ◽  
Vol 99 (2) ◽  
pp. e7-e7 ◽  
Author(s):  
R. G. Fisher ◽  
W. C. Gruber ◽  
K. M. Edwards ◽  
G. W. Reed ◽  
S. J. Tollefson ◽  
...  
Keyword(s):  
Respiratory Syncytial Virus ◽  
Virus Infection ◽  
Respiratory Syncytial Virus Infection ◽  
Vaccine Efficacy ◽  
Efficacy Trials ◽  
Syncytial Virus

scholarly journals Design of vaccine efficacy trials during public health emergencies

2019 ◽  
Vol 11 (499) ◽  
pp. eaat0360 ◽  
Author(s):  
Natalie E. Dean ◽  
Pierre-Stéphane Gsell ◽  
Ron Brookmeyer ◽  
Victor De Gruttola ◽  
Christl A. Donnelly ◽  
...  
Keyword(s):  
Public Health ◽  
Vaccine Efficacy ◽  
Vaccine Trial ◽  
Disease Outbreak ◽  
Public Health Emergencies ◽  
Efficacy Trials ◽  
Challenging Environment

Public health emergencies, such as an Ebola disease outbreak, provide a complex and challenging environment for the evaluation of candidate vaccines. Here, we outline the need for flexible and responsive vaccine trial designs to be used in public health emergencies, and we summarize recommendations for their use in this setting.

scholarly journals ANALYSIS OF IMMUNE RESPONSES ON TRANSGENIC TIGER SHRIMP (Penaeus monodon) AGAINST PATHOGENIC BACTERIUM Vibrio harveyi

2014 ◽  
Vol 9 (1) ◽  
pp. 23
Author(s):  
Andi Parenrengi ◽  
Bunga Rante Tampangallo ◽  
Andi Tenriulo
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Vibrio Harveyi ◽  
Gene Transfection ◽  
Penaeus Monodon ◽  
Pathogenic Bacterium ◽  
Shrimp Culture ◽  
Tiger Shrimp ◽  
Randomized Design ◽  
Study Results

Vibriosis is one of main diseases of the black tiger shrimp Penaeus monodon infected by pathogenic bioluminous bacterium Vibrio harveyi that can cause mass mortalities in shrimp culture. The bacteria can also trigger the disease white spot syndrome virus (WSSV). An effort to produce shrimp disease-resistant strains has been done through transgenesis technology with antiviral gene transfection. By this technology, it is expected an increase in the immune response of shrimp in a variety of diseasecausing pathogens. This study aimed to determine the immune responses (total haemocytes, haemocyte differentiation, and phenoloxydase activity) of transgenic tiger shrimp against pathogenic bacterium V. harveyi. Research using completely randomized design, which consists of two treatments and three replications. Test animals being used were transgenic and non-transgenic shrimp with size, weight 3.93±1.25 g and a total length of 7.59±0.87 cm. Treatments being tested were the injection of bacterium V. harveyi (density of 5x106 cfu/mL) of 0.1 mL/individual on transgenic (A) and non-transgenic shrimp (B). Immune response parameters such as total haemocytes, haemocyte differentiation, and phenoloxydase activity were observed on day 1, 3, and 6 days after challenging. Data were analyzed using t-test by SPSS software. The results showed that the total haemocyte of transgenic shrimp was not significantly different (P>0.05) from non-transgenic shrimp, but haemocyte differentiation and phenoloxydase activity were significantly different (P<0.05) especially on sixth days after being exposed to the bioluminescent bacteria. The study results implied that transgenic shrimp has a better immune response compared than non-transgenic shrimp.

scholarly journals Willingness to participate in HIV vaccine efficacy trials among high risk men and women from fishing communities along Lake Victoria in Uganda

Vaccine ◽  
2013 ◽  
Vol 31 (44) ◽  
pp. 5055-5061 ◽  
Author(s):  
Gershim Asiki ◽  
Andrew Abaasa ◽  
Eugene Ruzagira ◽  
Freddie Kibengo ◽  
Ubaldo Bahemuka ◽  
...  
Keyword(s):  
High Risk ◽  
Vaccine Efficacy ◽  
Lake Victoria ◽  
Hiv Vaccine ◽  
Fishing Communities ◽  
Willingness To Participate ◽  
Men And Women ◽  
Efficacy Trials

scholarly journals Pragmatic trials of complex psychosocial interventions: methodological challenges

2013 ◽  
Vol 22 (2) ◽  
pp. 105-109 ◽  
Author(s):  
G. Dunn
Keyword(s):  
Scientific Explanation ◽  
Psychosocial Interventions ◽  
Outcome Data ◽  
Adherence To Treatment ◽  
Technical Problems ◽  
Loss To Follow Up ◽  
Randomized Design ◽  
Subsequent Loss ◽  
Cluster Randomized

Having first introduced the pragmatic health care trial, the discussion then focuses on a selected list of technical problems that are important for the design, analysis and inference from such trials. The first is lack of independence of participants’ outcomes do to clustering either arising from a cluster randomized design or to the way treatment is delivered (therapist and group effects). The second and third concern the implications of non-adherence to treatment and subsequent loss to follow-up, particularly, when non-adherence is associated with missing outcome data. Finally, it is argued that pragmatism and a desire for a scientific explanation should not be regarded as mutually exclusive.

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