scholarly journals COVID-19: Salient Aspects of Coronavirus Infection, Vaccines and Vaccination Testing and their Implications

2021 ◽  
Author(s):  
Pradeep K. Pasricha ◽  
Arun K. Upadhayaya
Keyword(s):  
Probability Distribution ◽  
Incubation Period ◽  
Vaccine Efficacy ◽  
Mass Density ◽  
Negative Response ◽  
Cumulative Probability ◽  
Alveolar Cells ◽  
Uninfected Individual ◽  
Average Group ◽  
Coronavirus Infection

In the present study, three basic aspects related to COVID-19 are presented. (a) The occurrence of coronavirus infection is analyzed statistically as number of coronaviruses infected alveolar cells compared to normal alveolar cells in human lungs. The mole concept is used to estimate the number of normal alveolar cells per human lung. The number of coronavirus infections in infected alveolar cells is estimated from the published Lower Respiratory Tract (LRT) load data. The Poisson probability distribution is aptly applied to imply the incubation period of the coronavirus infection to be within day-3 to day-7, with the cumulative probability of 75%. The incubation period within day-0 to day-10 has a cumulative probability of 98%. It implies a 10-day quarantine to isolate an uninfected individual as a precautionary measure. (b) Three vaccines to combat COVID-19, which adopt distinct paradigms while preparing them, are analyzed. These are Moderna's mRNA-1273, Oxford-AstraZeneca's ChAdOx1 nCoV-19 and Bharat BioTech's COVAXIN. The mole concept is used to estimate the antigen mass density per dose of each of these vaccines as 10, 0.1 and 1 (g per cubic-cm), respectively. The vaccines are deemed to be compatible to neutralize the infection. (c) A statistical analysis is performed of the Moderna's mRNA-1273 vaccine efficacy of 94.1% and Oxford's ChAdOx1 nCoV-19 vaccine efficacy of 62.1% in terms of groups of volunteers testing negative to vaccine by chance. In the Moderna vaccination testing scenario, since the probability of negative response of vaccine is small, the Poisson probability distribution for 95% cumulative probability is used to describe the vaccination testing in 300 samples of 47 volunteers each. Thus, 87% of samples have average group of 3 volunteers testing negative to vaccine. About 6% of samples have all volunteers testing positive to vaccine. In the Oxford vaccination testing scenario, since the probability of negative response of vaccine is finite, the Gaussian probability distribution for 95% probability is used to describe the vaccination testing in 75 samples of 120 volunteers each. Thus, 68% of samples have average group of 45 volunteers testing negative to vaccine. No sample has all volunteers testing positive to vaccine. A vaccine, irrespective of its efficacy being high or low, is necessary for mass immunization.

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.

Branching design of the bronchial tree based on a diameter-flow relationship

1997 ◽  
Vol 82 (3) ◽  
pp. 968-976 ◽  
Author(s):  
Hiroko Kitaoka ◽  
Béla Suki
Keyword(s):  
Distribution Function ◽  
Probability Distribution ◽  
Probability Distribution Function ◽  
Design Method ◽  
Random Variable ◽  
Bronchial Tree ◽  
Cumulative Probability ◽  
Cumulative Probability Distribution ◽  
Tree Models ◽  
Flow Division

Kitaoka, Hiroko, and Béla Suki. Branching design of the bronchial tree based on a diameter-flow relationship. J. Appl. Physiol. 82(3): 968–976, 1997.—We propose a method for designing the bronchial tree where the branching process is stochastic and the diameter ( d) of a branch is determined by its flow rate (Q). We use two principles: the continuum equation for flow division and a power-law relationship between d and Q, given by Q ∼ d n, where n is the diameter exponent. The value of n has been suggested to be ∼3. We assume that flow is divided iteratively with a random variable for the flow-division ratio, defined as the ratio of flow in the branch to that in its parent branch. We show that the cumulative probability distribution function of Q, P(>Q) is proportional to Q−1. We analyzed prior morphometric airway data (O. G. Raabe, H. C. Yeh, H. M. Schum, and R. F. Phalen, Report No. LF-53, 1976) and found that the cumulative probability distribution function of diameters, P(> d), is proportional to d −n, which supports the validity of Q ∼ d n since P(>Q) ∼ Q−1. This allowed us to assign diameters to the segments of the flow-branching pattern. We modeled the bronchial trees of four mammals and found that their statistical features were in good accordance with the morphometric data. We conclude that our design method is appropriate for robust generation of bronchial tree models.

A Simple Coding Procedure Enhances a Neuron's Information Capacity

1981 ◽  
Vol 36 (9-10) ◽  
pp. 910-912 ◽  
Author(s):  
Simon Laughlin
Keyword(s):  
Information Theory ◽  
Probability Distribution ◽  
Response Function ◽  
Compound Eye ◽  
Information Capacity ◽  
Cumulative Probability ◽  
Natural Scenes ◽  
First Order ◽  
Contrast Response Function ◽  
Contrast Response

Abstract The contrast-response function of a class of first order intemeurons in the fly's compound eye approximates to the cumulative probability distribution of contrast levels in natural scenes. Elementary information theory shows that this matching enables the neurons to encode contrast fluctuations most efficiently.

Estimating the probability distribution of the incubation period for rabies using data from the 1948–1954 rabies epidemic in Tokyo

2016 ◽  
Vol 123 ◽  
pp. 102-105 ◽  
Author(s):  
Kageaki Tojinbara ◽  
K. Sugiura ◽  
A. Yamada ◽  
I. Kakitani ◽  
N.C.L. Kwan ◽  
...  
Keyword(s):  
Probability Distribution ◽  
Incubation Period ◽  
Using Data
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