PMID- 23391176
OWN - NLM
STAT- MEDLINE
DCOM- 20130823
LR  - 20130208
IS  - 1465-3338 (Electronic)
IS  - 0307-9457 (Linking)
VI  - 42
IP  - 1
DP  - 2013 Feb
TI  - The required sample size in vaccination-challenge experiments with infectious 
      bronchitis virus, a meta-analysis.
PG  - 9-16
LID - 10.1080/03079457.2012.751485 [doi]
AB  - For statistical, animal welfare and financial reasons the choice of the number of 
      chickens per group in experiments is important. This estimation, together with 
      the number of tracheal organ cultures (TOCs) that need to be examined from each 
      chicken in order to assess protection, should be based on the difference in level 
      of protection that one would like to be able to detect (effect size), the 
      expected variability of the results between and within the chickens, the desired 
      confidence level and the power of the study. To obtain data that would facilitate 
      this estimation, a meta-analysis was performed on the data from 18 infectious 
      bronchitis virus (IBV) vaccination-challenge experiments performed at the Dutch 
      Animal Health Service Deventer, the Netherlands (GD) in order to determine and 
      quantify the source of variation in the mean level of protection of different 
      groups. For the calculations, 137 groups of chickens were subdivided into 10 
      clusters based on age (young or adult), vaccination (none, homologous or 
      heterologous), challenge (IBV or mock infected) and location of vaccination 
      (isolator at GD or in the field). The results were used to estimate the required 
      number of chickens per group for the different clusters using 2, 5 or 10 TOCs per 
      chicken to be able to detect effect sizes of 6.25%, 12.5%, 25% and 50% between 
      groups of chickens with 95% confidence (P<0.05) and 80% power. The number of 
      chickens that was required for the mentioned effect sizes varied greatly from 2 
      to 650. This meta-analysis provided data that allow research workers to estimate 
      the number of chickens that should be included in each group in order to obtain 
      reliable results based on particular combinations of infectious bronchitis 
      vaccination and challenge strains as defined by the presented clusters.
FAU - de Wit, J J
AU  - de Wit JJ
AD  - GD (Animal Health Service) , P.O. Box 9, 7400 AA, Deventer, the Netherlands. 
      j.d.wit@gddeventer.com
FAU - Boelm, G J
AU  - Boelm GJ
FAU - van Gerwe, T J W M
AU  - van Gerwe TJ
FAU - Swart, W A J M
AU  - Swart WA
LA  - eng
PT  - Journal Article
PT  - Meta-Analysis
PL  - England
TA  - Avian Pathol
JT  - Avian pathology : journal of the W.V.P.A
JID - 8210638
RN  - 0 (Antibodies, Viral)
RN  - 0 (Viral Vaccines)
SB  - IM
MH  - Animals
MH  - Antibodies, Viral/analysis
MH  - Binomial Distribution
MH  - *Chickens
MH  - Cluster Analysis
MH  - Coronavirus Infections/prevention & control/*veterinary/virology
MH  - Female
MH  - Infectious bronchitis virus/*immunology
MH  - Male
MH  - Netherlands
MH  - Organ Culture Techniques/statistics & numerical data/veterinary
MH  - Poultry Diseases/*prevention & control/virology
MH  - Sample Size
MH  - Specific Pathogen-Free Organisms
MH  - Trachea/immunology
MH  - Vaccination/*veterinary
MH  - Viral Vaccines/*immunology
EDAT- 2013/02/09 06:00
MHDA- 2013/08/24 06:00
CRDT- 2013/02/09 06:00
PHST- 2013/02/09 06:00 [entrez]
PHST- 2013/02/09 06:00 [pubmed]
PHST- 2013/08/24 06:00 [medline]
AID - 10.1080/03079457.2012.751485 [doi]
PST - ppublish
SO  - Avian Pathol. 2013 Feb;42(1):9-16. doi: 10.1080/03079457.2012.751485.