Summary of A/Cal infectivity in nasal washes.

<p>Panel (a) shows ferrets infected with A/Cal on day 0 and treated with 300 µg 244 DI virus (▪) or infected and treated with 300 µg inactivated 244 DI virus (▴); another group was not infected but treated with 300 µg of active 244 DI virus (•). A standard preparation of A/Cal virus was used to normalise titrations carried out on different days. These varied by less than 4-fold. The dotted line is the limit of sensitivity of the assay (1.92 log₁₀ FFU/ml). Significant reduction in infectivity (by a two-tailed Mann-Whitney U test) in ferrets treated with 244 DI virus is denoted by **. Panels (b) and (c) show details of the statistical analysis on day 2 and 3, respectively.</p

Summary of 244 DI virus-mediated protection of ferrets from influenza caused by A/Cal.

*<p> <b>Statistically significant at ≥95% confidence limits; data presented elsewhere in this report.</b></p><p> <b>ND, not done.</b></p

Statistical analysis of summed clinical signs for each day in ferrets re-challenged with A/Cal.

<p>The group that previously experienced A/Cal+300 ug 244 DI virus (▪) is compared with the group that previously experienced only saline (▴). The p value was determined using a one tailed Mann-Whitney U test.</p

Changes in weight of ferrets over the course of infection with A/Cal.

<p>Shown is the mean group body weight changes in A/Cal influenza virus-infected ferrets treated with (a) 300 µg 244 DI virus (▪) or inactivated 244 DI virus (▴), (b) 30 µg 244 DI virus (▪) or inactivated 244 DI virus (▴). (c) Shows the weight changes in ferrets inoculated with saline (○) or treated with 300 µg of active 244 DI virus (•). Data are expressed as a percentage change compared to the group average weight at day 0. The statistical significance of body weight changes on any one day was determined by a one tailed unpaired t-test and is indicated by an asterisk (p≤0.05).</p

244 DI virus (244) RNA is amplified in nasal washes by A/Cal.

<p>Ferrets were infected with A/Cal on day 0 and treated with 244 DI virus or inactivated 244 DI virus. Levels of 244 DI RNA were determined by quantitative RT-PCR. Mean 244 RNA copy numbers for each ferret group (n = 5) are plotted. Panel (a) shows ferrets that were infected with A/Cal influenza virus and treated with 300 µg 244 DI virus (▪), or 30 µg 244 DI virus (▴), or 300 µg (i) inactivated 244 DI virus (▾), or 30 µg (i) inactivated 244 DI virus (⧫). Panel (b) shows non-infected ferrets that were given 300 µg 244 DI virus (□), or diluent (▵). The dotted line shows the limit of detection. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0049394#pone.0049394.s001" target="_blank">Figure S1</a> gives details for individual animals.</p

The percentage of total RNA collected in each stage (size range) of the May impinger compared based on the WHO 2009 AGP definitions.

<p>The percentage of total RNA collected in each stage (size range) of the May impinger compared based on the WHO 2009 AGP definitions.</p

Analysis of the air samples using the WHO (2007) AGP definitions and including chest physiotherapy.

a<p>Sample considered positive if aerosol <7.3 µm indicated the present of H1N1.</p>b<p>n unique patients refers to the number of patients these samples were taken from.</p><p>Column A: Results from univariable logistic regression models examining potential risk factors for production of H1N1 positive aerosol. Sample considered positive if aerosol <7.3 µm indicated the presence of H1N1. Estimates adjusted for repeated measurements.</p><p>Column B: Results from univariable negative binomial regression models examining potential risk factors for copy number per litre per minute given H1N1 positive aerosol.</p><p>A hyphen (-) indicates no positive samples in category. Referent refers to the category of an ordinal or nominal variable against which other categories are compared in the regression model and for which <i>no</i> dummy variable is included in the regression model.</p

The recruitment and data analysis flowchart.

<p>The recruitment and data analysis flowchart.</p

Risk summary stratification table.

a<p>Probabilities obtained from univariable logistic regression models examining potential risk factors for production of H1N1 positive aerosol. Sample considered positive if aerosol <7.3 µm indicated the presence of H1N1. Estimates adjusted for repeated measurements.</p>b<p>Estimates obtained from univariable negative binomial regression models examining potential risk factors for copy number per litre per minute given H1N1 positive aerosol.</p

In December 2009 the World Health Organization (WHO) updated its advice on AGPs.

<p>N.B. Chest physiotherapy is now not considered an AGP but advice states that a surgical mask should be worn by the patient if tolerated and HCWs should wear PPE as recommended for routine care (i.e. a surgical mask) during the procedure.</p