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Table 1 A comparison of multiplication factors (MFs) for salmonellosis in several countries

From: Measuring underreporting and under-ascertainment in infectious disease datasets: a comparison of methods

Country Underestimation MF Primary study type Study Under-ascertainment MF Primary study type Study Underreporting MF Primary study type Study
Austria 3 RTS [75]       
Austria 11 RTS [76]       
Belgium 1.9 RTS [75]       
Belgium 3.5 RTS [76]       
Bulgaria 271 RTS [75]       
Bulgaria 718.5 RTS [76]       
Croatia 30.6 RTS [75]       
Cyprus 71.2 RTS [75]       
Cyprus 173.2 RTS [76]       
Czech Republic 3 RTS [75]       
Czech Republic 28.9 RTS [76]       
Denmark 1.8 RTS [75]       
Denmark 4.4 RTS [76]       
Denmark 17 PRC [9]       
Denmark NT UEinf: 325 (5-95% quartiles: 190–505) Sero/MOD [77]       
Estonia 1.3 RTS [75]       
Estonia 16.9 RTS [76]       
Finland 0.6 RTS [75]       
Finland 0.4 RTS [76]       
France 8.3 RTS [75]     S.entd. $ : Data1: 7.1(95% CI: 6.7-7.7) CRS [78]
Data2: 12.5 (95% CI: 11.1-14.3)
Data3: 2 (95% CI: 1.9-2.2)
Spp other than S.entd.& S.typh.
Data1: 12.5 (95% CI: 7.1-16.7)
Data2: 16.6 (95% CI: 10–25)
Data3: 2.0 (95% CI: 1.1-2.8)
France 26.9 RTS [76]       
Germany 1.8 RTS [75]       
Germany 9.8 RTS [76]       
Germany 6.7 PRC [9]       
Greece 97.7 RTS [75]     1.75 MOD/RC [79]
Greece 1228.5 RTS [76]       
Greece 51.45 (PERT: 3.2; 99.7) BoD/CRS [80]       
Hungary 5.5 RTS [75]       
Hungary 66.8 RTS [76]       
Ireland 4.3 RTS [75]       
Ireland 5.4 RTS [76]       
Italy 13.1 RTS [75]       
Italy 71.7 RTS [76]       
Italy 17 PRC [9]       
Latvia 11.7 RTS [75]       
Latvia 44.3 RTS [76]       
Lithuania 10 RTS [75]       
Lithuania 59.1 RTS [76]       
Luxembourg 4.5 RTS [76]       
Malta 92.6 RTS [75]       
Malta 222.7 RTS [76]       
Poland 16.2 RTS [75]       
Poland 114.1 RTS [76]       
Poland 18 PRC [9]       
Portugal 378 RTS [75]       
Portugal 2082.9 RTS [76]       
Romania 332 RTS [75]       
Romania 349.9 RTS [76]       
Slovakia 3.5 RTS [75]       
Slovakia 53.2 RTS [76]       
Slovenia 10 RTS [75]       
Slovenia 40.3 RTS [76]       
Spain 103 RTS [75]       
Spain 214.2 RTS [76]     NT: Data 1 = 2.0 (95% CI: 2.0 - 2.1) CRS [81]
Data 2 = 1.5 (95% CI: 1.4 - 1.5)
Sweden 0.5 RTS [76]       
Sweden 10 PRC [9]     Data 1 =1.05, Data 2 =1.02 CRS [82]
The Netherlands 7.7 RTS [75]       
The Netherlands 26.3 (ref) RTS [76]       
The Netherlands 24.7 (5-95% quartiles: 5.2 - 64.7) BRI/BoD [57] 5.8 (5-95% quartiles: 0.8 - 25.6) BRI [57] 4.3 (5-95% quartiles: 2.5 - 6.5) BRI [57]
The Netherlands 14 (5-95% quartiles: 3.6 – 56) CBS/BoD [56] 6.5 (5-95% quartiles: 0.0 - 20) CBS/BoD [56]    
The Netherlands 14.3 LAB [62]       
The Netherlands 20 PRC [9]       
United Kingdom 4.3 RTS [75]       
United Kingdom 7.3 RTS [76]       
United Kingdom 4.7 (95% CI : 1.2 - 18.2) CBS [47] 3.4 (95% CI: 0.4 - 32.2) CBS [47] 1.4 (95% CI: 0.6 - 3.3) CBS [47]
United Kingdom 3.2 (95% CI : 1.4 - 12.0) CBS [2] GP only, 1.4 (95% CI: 0.7 - 2.8) CBS [2]    
United Kingdom 40 PRC [9]       
United Kingdom NT, UElab: 3.9 CBS/BoD [55]       
EU-27 (excl.Croatia) 57.5 (11–140) RTS [76]       
Iceland 0.4 RTS [75]       
Norway 1.0 (ref) RTS [75]       
Norway 1.2 RTS [76]       
Switzerland 7.1 RTS [76]       
USA NT, UElab: BD 9.8, NBD 67.7, total 38.6 CBS/BoD [49] NT, BD 6.8, NBD 8.6 [49]     
USA NT, 38 (taken from [49]) BoD [83] NT, BD - 2.86 (PERT 1.96 – 5.26) BoD [84] NT UN, 1   [84]
NBD – 5.56 (PERT 5–6.67)
Canada 13 - 37 PM [85]       
Australia ‡BD:1-2d: 11.39 (95% CrI: 8.49–16.36) PM [33] ‡BD: 1-2d: 10 (95% CrI: 7.1-14.3)   [33]    
3-4d: 2.82 (95% CrI: 2.17–3.98)    3-4d: 2.3 (95% CrI: 1.9-3.2)
  ≥5d: 1.81 (95% CrI: 1.33–2.72)    ≥5d: 1.5 (95% CrI: 1.1-2.2)      
NBD: 1-2d 143.29 (95% CrI: 83.3–371) NBD; 1-2d: 10 (95% CrI: 7.1-14.3)
3-4d 13.06 (95% CrI: 6.37–67.83) 3-4d: 2.3 (95% CrI: 1.9-3.2)
≥5d 3.93 (95% CrI: 2.10–11.92) ≥5d: 1.5 (95% CrI: 1.1-2.2)
Overall: 7 (95% CrI: 4–16)
Japan 74.0 (5-95% quartiles: 35.8, 140.7) CBS [50] S.brae. Age <10 years: 1.2, CBS [48]    
> = 10 years: 1.7, Overall:1.6,
  1. 1. This table lists all extracted or derived MFs (with variance shown as 95% CI, 95% CrI, PERT distribution (max, min, mode), or 5-95% quartiles where available) from relevant studies found during the extensive literature review. MFs give an estimation of the extent of UE (combined UA and UR), UA and UR for salmonellosis in a particular country; the higher the MF, the higher the proportion of cases not captured by the surveillance system. These MFs could be applied to official figures as reported by public health agencies to adjust for UE and give a new estimate of total symptomatic infections occurring in a population at a given time. Exceptions include; “UEinf” where the MF can adjust official figures from public health agencies and give a new estimate of total infections (both symptomatic and asymptomatic) occurring in a population at a given time, and “UElab” where the MF can adjust official laboratory figures of laboratory confirmed infections and give a new estimate of total infections (both symptomatic and asymptomatic) occurring in a population at a given time. MFs of UA and UR can be multiplied together to make one MF of UE.
  2. 2. Study types abbreviations: CBS: Community-based study, RTS: Returning traveller study, CRS: Capture-recapture study, PRC: Pyramid reconstruction model, BRI: Bayesian risk of infection model, BoD: Burden of disease calculation, Sero: Analysis of serology data, LAB: Analysis of laboratory surveillance, RC: Analysis of reporting completeness, PM: Probability model, OUT: Outbreak analysis, MOD: Modelling other. Symptoms abbreviations: NT: Non-typhoidal salmonellosis; NBD: Non-bloody diarrhoea; BD: Bloody diarrhoea; severity of diarrhoea (d = days). Salmonella species abbreviations: S.entd. : S. enteritidis; S.typh. : S.typhimurium; S.brae. : S.braenderup.Other abbreviations: UN: Under-notification of laboratory confirmed infection; GP only: cases attending GP surgeries (not hospitals) only; $ Estimates corrected by the positive predictive value of one data source where (unlike the other two sources) notifications are not validated by a systematic procedure; ‡ No. cases in the community for every 100 reported.
  3. 3. For CRS, a MF is given to correct for UR for each data source (i.e. MF for 'Data 1’ will estimate the underreporting in data source 1). For MFs estimated in the same RTS, one country will be listed as the reference country (i.e. 'ref’) and all other countries compared to this.
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BMC Public Health

ISSN: 1471-2458

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