Right sizing for vaccine effectiveness studies: how many is enough for reliable estimation?

2019 ◽  
Vol 43 ◽  
Author(s):  
Olivia H Price ◽  
Kylie S Carville ◽  
Sheena G Sullivan
Keyword(s):  
Sample Size ◽  
Odds Ratio ◽  
Sampling Methods ◽  
Vaccine Effectiveness ◽  
Sentinel Surveillance ◽  
Age Group ◽  
Scarce Resources ◽  
Point Estimates ◽  
Effectiveness Studies ◽  
Arbitrary Rate

Background The precision of vaccine effectiveness (VE) estimates is dependent on sample size and sampling methods. In Victoria, participating general practitioners (GPs) are not limited by the number of influenza-like illness (ILI) patients they collect respiratory samples (swabs) from in sentinel surveillance. However, in the context of scarce resources it is of interest to determine the minimum sample size needed for reliable estimates. Methods Following the test-negative design, patients with ILI were recruited by GPs and tested for influenza. Descriptive analyses were conducted to assess possible selection bias introduced by GPs. VE was calculated by logistic regression as [1 – odds ratio] x 100% and adjusted for week of presentation and age. Random 20% and 50% samples were selected without replacement to estimate the effect of swab rates on VE estimates. Results GPs swabbed a smaller proportion of patients aged ≥65 years (45.9%, n=238) than those <5 (75.6%, n=288), 5–17 (67.9%, n=547) and 18–64 (75.6%, n=2662) years. Decreasing the swab rate did not alter VE point estimates significantly. However, it reduced the precision of estimates and in some instances resulted in too small a sample size to estimate VE. Conclusion Imposing a 20% or 50% swabbing rate produces less robust VE estimates. The number of swabs required per year to produce precise estimates should be dictated by seasonal severity, rather than an arbitrary rate. It would be beneficial for GPs to swab patients systematically by age group to ensure there are sufficient data to investigate VE against a particular subtype in a given age group.

scholarly journals Pooled influenza vaccine effectiveness estimates for Australia, 2012–2014

2016 ◽  
Vol 144 (11) ◽  
pp. 2317-2328 ◽  
Author(s):  
S. G. SULLIVAN ◽  
K. S. CARVILLE ◽  
M. CHILVER ◽  
J. E. FIELDING ◽  
K. A. GRANT ◽  
...  
Keyword(s):  
General Practice ◽  
Logistic Regression ◽  
Confidence Interval ◽  
Influenza Vaccine ◽  
Sample Size ◽  
Vaccine Coverage ◽  
Vaccine Effectiveness ◽  
Influenza Surveillance ◽  
Influenza B ◽  
Age Group

SUMMARYData were pooled from three Australian sentinel general practice influenza surveillance networks to estimate Australia-wide influenza vaccine coverage and effectiveness against community presentations for laboratory-confirmed influenza for the 2012, 2013 and 2014 seasons. Patients presenting with influenza-like illness at participating GP practices were swabbed and tested for influenza. The vaccination odds of patients testing positive were compared with patients testing negative to estimate influenza vaccine effectiveness (VE) by logistic regression, adjusting for age group, week of presentation and network. Pooling of data across Australia increased the sample size for estimation from a minimum of 684 to 3,683 in 2012, from 314 to 2,042 in 2013 and from 497 to 3,074 in 2014. Overall VE was 38% [95% confidence interval (CI) 24–49] in 2012, 60% (95% CI 45–70) in 2013 and 44% (95% CI 31–55) in 2014. For A(H1N1)pdm09 VE was 54% (95% CI–28 to 83) in 2012, 59% (95% CI 33–74) in 2013 and 55% (95% CI 39–67) in 2014. For A(H3N2), VE was 30% (95% CI 14–44) in 2012, 67% (95% CI 39–82) in 2013 and 26% (95% CI 1–45) in 2014. For influenza B, VE was stable across years at 56% (95% CI 37–70) in 2012, 57% (95% CI 30–73) in 2013 and 54% (95% CI 21–73) in 2014. Overall VE against influenza was low in 2012 and 2014 when A(H3N2) was the dominant strain and the vaccine was poorly matched. In contrast, overall VE was higher in 2013 when A(H1N1)pdm09 dominated and the vaccine was a better match. Pooling data can increase the sample available and enable more precise subtype- and age group-specific estimates, but limitations remain.

scholarly journals Monitoring field establishment of the emerald ash borer biocontrol agent Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae): Sampling methods, sample size, and phenology

2021 ◽  
Vol 156 ◽  
pp. 104535
Author(s):  
Toby R. Petrice ◽  
Leah S. Bauer ◽  
Deborah L. Miller ◽  
John S. Stanovick ◽  
Therese M. Poland ◽  
...  
Keyword(s):  
Sample Size ◽  
Biocontrol Agent ◽  
Sampling Methods ◽  
Emerald Ash Borer

scholarly journals Predictors of postpartum family planning in Rwanda: the influence of male involvement and healthcare experience

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Pamela Williams ◽  
Nicole Santos ◽  
Hana Azman-Firdaus ◽  
Sabine Musange ◽  
Dilys Walker ◽  
...  
Keyword(s):  
Mental Health ◽  
Health Status ◽  
Family Planning ◽  
Locus Of Control ◽  
Sample Size ◽  
Odds Ratio ◽  
Male Involvement ◽  
Mental Health Status ◽  
Respectful Maternity Care ◽  
Postpartum Family Planning

Abstract Background Strengthened efforts in postpartum family planning (PPFP) is a key priority to accelerate progress in reproductive, maternal, newborn, and child health outcomes. This secondary data analysis explores factors associated with PPFP uptake in Rwanda. The purpose of this study was to explore variables that may influence PPFP use for postpartum women in Rwanda including health facility type, respectful maternity care, locus of control, and mental health status. Methods This secondary analysis of data from a cluster randomized control trial used information abstracted from questionnaires administered to women (≥ 15 years of age) at two time points—one during pregnancy (baseline) and one after delivery of the baby (follow-up). The dependent variable, PPFP uptake, was evaluated against the independent variables: respectful care, locus of control, and mental health status. These data were abstracted from linked questionnaires completed from January 2017 to February 2019. The sample size provided 97% power to detect a change at a 95% significance level with a sample size of 640 at a 15% effect size. Chi-square testing was applied for the bivariate analyses. A logistic regression model using the generalized linear model function was performed; odds ratio and adjusted (by age group and education group) odds ratio with 95% confidence interval were reported. Results Of the 646 respondents, although 92% reported not wanting another pregnancy within the next year, 72% used PPFP. Antenatal care wait time (p =  < 0.01; Adj OR (Adj 95% CI) 21–40 min: 2.35 (1.46,3.79); 41–60 min: 1.50 (0.84,2.69); 61–450 min: 5.42 (2.86,10.75) and reporting joint healthcare decision-making between the woman and her partner (male) (p = 0.04; Adj OR (Adj 95% CI) husband/partner: 0.59 (0.35,0.97); mother and partner jointly: 1.06 (0.66,1.72) were associated with PPFP uptake. Conclusions These results illustrate that partner (male) involvement and improved quality of maternal health services may improve PPFP utilization in Rwanda.

Predicting the Effectiveness of the Pfizer-BioNTech BNT162b2 Vaccine from SARS-CoV-2 Variants Neutralisation Data

2021 ◽  
Author(s):  
Oleg Volkov ◽  
Svetlana Borozdenkova ◽  
Alexander Gray
Keyword(s):  
Real Life ◽  
Vaccine Effectiveness ◽  
Vaccine Protection ◽  
Life Effectiveness ◽  
Correlates Of Protection ◽  
Antibody Titres ◽  
Effectiveness Studies

Modelling frameworks for vaccine protection are sorely needed to fight the Covid-19 pandemic with vaccines. We propose such a framework for the BNT162b2 and potentially other vaccines. It identifies correlates of protection based on live SARS-CoV-2 variants neutralising antibody titres from vaccinated individuals. We applied it to predict vaccine effectiveness in overall populations and age subgroups. It was validated by predicting effectiveness against the B.1.167.2 (Delta) variant. The predictions, of 51.7% (34%, 69%) after one and of 88.6% (76%, 97%) after two vaccine doses, were close to the corresponding means, 49% and 85.4%, of observations in real-life effectiveness studies. We illustrate its applications to inform decisions, such as about the doses and timing of vaccine boosters.

scholarly journals DESCRIPTIVE EPIDEMIOLOGY OF STEPHANOFILARIASIS (HUMPSORE) IN CATTLE

2017 ◽  
Vol 14 (2) ◽  
pp. 167-170
Author(s):  
M. Akter BJVM ◽  
M. K. Hassan ◽  
M. Ahammed ◽  
M. A. Ali ◽  
G. C. Biswas ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Neck Region ◽  
Clinical History ◽  
P Value ◽  
Age Group ◽  
Descriptive Epidemiology ◽  
Direct Examination ◽  
Local Breed ◽  
Female Cattle ◽  
Age And Sex

An epidemiological study was conducted to investigate the epidemiology of humpsore (stephanofilariasis) infection on cattle of different age and sex by collecting information from samples conveniently from different areas of Mymensingh district in Bangladesh. Clinical history and direct examination is done to detect the infection. Out of 503 samples total 43.14% cattle were found stephanofilariasis positive. The prevalence of stephanofilariasis was higher (27.24%) in cattle between 5-10 years old cattle than of less than 5 years (10.93%) and more than 10 years (4.97%) old cattle. Females have shown more positive (36.98%) result than male (male entire= 3.18%, male castrated= 2.98%) that was 6.16% (Odds ratio= 1; P value= 0.987, ?2= 0.003). Local breed shown 36.98% positive to stephanofilariasis followed in descending order by 2.98% in Red Sindhi, 0.99% in Sahiwal, 0.80% in Jersey cross, 0.40% in Holstein cross, Haryana and Red Chittagong breeds and 0.20% in Pabna breed. From the study it is shown that highest (14.1%) prevalence found in the location of neck region of local breed (12.72%) in female cattle (12.52%) and in the age group of 5-10years (9.74%) than other category on the basis of location of lesions.

scholarly journals Biostatistical Analysis: A Primer for Clinical Exercise Physiology, Part 1

2018 ◽  
Vol 7 (3) ◽  
pp. 63-69
Author(s):  
Suzanne L. Havstad ◽  
George W. Divine
Keyword(s):  
Sample Size ◽  
Gold Standard ◽  
Exercise Physiology ◽  
Analytical Techniques ◽  
Multiple Comparisons ◽  
Inference Process ◽  
P Values ◽  
Advantages And Disadvantages ◽  
Point Estimates ◽  
Biostatistical Analysis

ABSTRACT In this first of a two-part series on introductory biostatistics, we briefly describe common designs. The advantages and disadvantages of six design types are highlighted. The randomized clinical trial is the gold standard to which other designs are compared. We present the benefits of randomization and discuss the importance of power and sample size. Sample size and power calculations for any design need to be based on meaningful effects of interest. We give examples of how the effect of interest and the sample size interrelate. We also define concepts helpful to the statistical inference process. When drawing conclusions from a completed study, P values, point estimates, and confidence intervals will all assist the researcher. Finally, the issue of multiple comparisons is briefly explored. The second paper in this series will describe basic analytical techniques and discuss some common mistakes in the interpretation of data.

Null Hypothesis Significance Testing: Ramifications, Ruminations and Recommendations

2005 ◽  
Vol 35 (1) ◽  
pp. 1-20 ◽  
Author(s):  
G. K. Huysamen
Keyword(s):  
Sample Size ◽  
Confidence Intervals ◽  
Effect Size ◽  
Null Hypothesis ◽  
Significance Testing ◽  
Population Parameter ◽  
Size Estimation ◽  
Null Hypothesis Significance Testing ◽  
Point Estimates ◽  
Size Estimates

Criticisms of traditional null hypothesis significance testing (NHST) became more pronounced during the 1960s and reached a climax during the past decade. Among others, NHST says nothing about the size of the population parameter of interest and its result is influenced by sample size. Estimation of confidence intervals around point estimates of the relevant parameters, model fitting and Bayesian statistics represent some major departures from conventional NHST. Testing non-nil null hypotheses, determining optimal sample size to uncover only substantively meaningful effect sizes and reporting effect-size estimates may be regarded as minor extensions of NHST. Although there seems to be growing support for the estimation of confidence intervals around point estimates of the relevant parameters, it is unlikely that NHST-based procedures will disappear in the near future. In the meantime, it is widely accepted that effect-size estimates should be reported as a mandatory adjunct to conventional NHST results.

Lifespan Prudence

2021 ◽  
pp. 50-84
Author(s):  
Juliana Uhuru Bidadanure
Keyword(s):  
Age Groups ◽  
Age Group ◽  
Veil Of Ignorance ◽  
Scarce Resources ◽  
Unequal Treatment ◽  
Critical Engagement ◽  
Simple Realization

How should a just government distribute resources like jobs, education and healthcare between age groups? How should it ensure that the rules that govern entitlements and restrictions at different stages of our lives are fair rather than age-biased? This chapter answers these questions starting from Norman Daniels’s account of lifespan prudence. Daniels proposes that the unattractive allegory of a war between young and old could be undercut by the simple realization that we can all benefit from some forms of unequal treatment by age. He asks us to convert the interpersonal question into the intrapersonal question “how would an ideally placed agent behind a veil of ignorance distribute scarce resources between different stages of her own life?” This chapter offers an in-depth critical engagement with the framework and offers two resulting principles of age-group justice: lifespan sufficiency and lifespan efficiency.

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