Background
Methods
GrippeNet.fr data collection
Study period
Study participants
ILI case definitions
Statistical analyses
Results
Participation
2012/13 | 2013/14 | 2014/15 | 2015/16 | 2016/17 | 2017/18 | |
---|---|---|---|---|---|---|
Epidemic periods (starting week-ending week; number of epidemic weeks)a | 2012w51-2013w11 (13 weeks) | 2014w05-2014w09 (5 weeks) | 2015w03-2015w11 (9 weeks) | 2016w04-2016w14 (11 weeks) | 2016w50-2017w05 (8 weeks) | 2017w50-2018w10 (13 weeks) |
GN registered individualsb, N | 6046 | 5907 | 6632 | 6515 | 6234 | 5958 |
GN participants included in the studyc, n (%) | 2943 (49%) | 4140 (70%) | 4428 (67%) | 4780 (73%) | 4204 (67%) | 4158 (70%) |
Symptoms surveys filled in by the included participants, N | 58,235 | 76,578 | 80,106 | 99,333 | 73,711 | 82,252 |
Included participants having at least one ILI episode during the epidemic period (ILIECDC definition), n (%) | 866 (29%) | 469 (11%) | 886 (20%) | 829 (17%) | 787 (19%) | 855 (21%) |
Included participants having at least one ILI episode during the epidemic period (GNILI- definition), n (%) | 231 (8%) | 111 (3%) | 251 (6%) | 203 (4%) | 174 (4%) | 198 (5%) |
Description of the participants
2012/13–2017/18 study periodb N = 6992 | Metropolitan France general population (Inseea, 2015 data) N = 64,604,773 | |
---|---|---|
Sociodemographic characteristics | ||
Gender (m.d. = 0) | ||
Female | 4258 (61%) | 52% |
Male | 2734 (39%) | 48% |
Age (m.d. = 10) | ||
[0–5) | 109 (2%) | 6% |
[5–15) | 384 (5%) | 12% |
[15–45) | 1900 (27%) | 37% |
[45–65) | 2577 (37%) | 26% |
[65–75) | 1567 (22%) | 10% |
75 | 445 (6%) | 9% |
Household composition (m.d. = 16) | ||
Living alone | 1063 (15%) | 36% |
Living with ≥1 child | 2435 (35%) | 32% |
Living with adults only | 3478 (50%) | 32% |
Occupation (m.d. = 123) | ||
Working | 3345 (49%) | 40% |
Student | 774 (11%) | 24% |
Unemployed | 160 (2%) | 10% |
Retired | 2321 (34%) | 25% |
Stay at home/Sick leave | 266 (4%) | – |
Place of residency (m.d. = 0) | ||
Urban | 5637 (81%) | 77% |
Rural | 1355 (19%) | 23% |
Lifestyle | ||
Use of public transport (m.d. = 0) | 1169 (17%) | – |
Individuals’ contacts (m.d. = 0) | ||
Contact with patients | 728 (10%) | – |
Contact with elderly | 721 (10%) | – |
Contact with a group of people (≥10) | 2268 (32%) | – |
Contact with children | 1788 (26%) | – |
At least one pet at home (m.d. = 14) | 3199 (46%) | – |
Health characteristics | ||
Influenza vaccination (current season) (m.d. = 6) | 2517 (36%) | – |
Smokers (m.d. = 7) | 766 (11%) | – |
At least one health comorbidityc (m.d. = 0) | 1504 (22%) | – |
Chronic treatment c for: (m.d. = 0) | ||
Asthma | 441 (6%) | – |
Diabetes | 263 (4%) | – |
Heart diseases | 686 (10%) | – |
Kidney diseases | 50 (1%) | – |
Immunosuppression | 210 (3%) | – |
Pulmonary diseases | 195 (3%) | – |
At least one respiratory allergy (m.d. = 0) | 2413 (35%) | – |
BMI (m.d. = 139) | ||
Underweight | 348 (5%) | – |
Normal weight | 3946 (58%) | – |
Overweight | 1799 (26%) | – |
Obese | 760 (11%) | – |
Estimations of ILI episodes
Risk factor analyses: univariate and multivariate analyses
Na | Casesb n (%) | OR [CI 95%] Univariate analyses | p-value | OR [CI 95%] Multivariate analysis | p-value | ||
---|---|---|---|---|---|---|---|
Season | 2012/13 | 2943 | 866 (29%) |
Ref.
| <10−4 |
Ref.
| <10− 4 |
2013/14 | 4140 | 469 (11%) | 0.31 [0.27;0.34] | 0.30 [0.26;0.33] | |||
2014/15 | 4428 | 886 (20%) | 0.59 [0.54;0.66] | 0.60 [0.54;0.67] | |||
2015/16 | 4780 | 829 (17%) | 0.50 [0.45;0.55] | 0.50 [0.45;0.56] | |||
2016/17 | 4204 | 787 (19%) | 0.54 [0.49;0.60] | 0.57 [0.51;0.63] | |||
2017/18 | 4158 | 855 (21%) | 0.61 [0.55;0.68] | 0.64 [0.57;0.71] | |||
Sociodemographic characteristics | |||||||
Gender | Male | 9742 | 1623 (17%) |
Ref.
| <10−4 |
Ref.
| <10−4 |
Female | 14,911 | 3069 (21%) | 1.30 [1.20;1.40] | 1.29 [1.20;1.40] | |||
Age | [45–65) | 9940 | 1959 (20%) |
Ref.
| <10−4 |
Ref.
| <10− 4 |
[0–5) | 306 | 111 (36%) | 2.27 [1.78;2.89] | 3.12 [2.05;4.68] | |||
[5–15) | 1133 | 279 (25%) | 1.32 [1.12;1.55] | 1.53 [1.17;2.00] | |||
[15–45) | 5948 | 1309 (22%) | 1.15 [1.06;1.25] | 1.13 [1.03;1.25] | |||
[65–75) | 6003 | 885 (15%) | 0.71 [0.65;0.78] | 0.88 [0.77;1.01] | |||
≥75 | 1300 | 146 (11%) | 0.54 [0.45;0.65] | 0.70 [0.56;0.87] | |||
Household composition | Living alone | 3917 | 731 (19%) | Ref. | <10−4 | NS | NS |
Living with ≥1 child | 7712 | 1714 (22%) | 1.25 [1.12;1.40] | ||||
Living with adults only | 12,953 | 2234 (17%) | 0.92 [0.83;1.02] | ||||
Occupation | Working | 11,587 | 2432 (21%) | Ref. | <10−4 | Ref. | <10−2 |
Student | 2162 | 543 (25%) | 1.25 [1.11;1.41] | 1.02 [0.83;1.26] | |||
Unemployed | 575 | 138 (24%) | 1.18 [0.96;1.46] | 1.18 [0.95;1.46] | |||
Retired | 8932 | 1299 (15%) | 0.64 [0.59;0.70] | 0.80 [0.70;0.91] | |||
0.84 [0.70;1.02] | |||||||
Stay at home/ Sick leave | 993 | 191 (19%) | 0.89 [0.74;1.07] | ||||
Place of residency | Rural | 4840 | 906 (19%) |
Ref.
| 0.67 | – | – |
Urban | 19,813 | 3786 (19%) | 1.02 [0.93;1.12] | ||||
Lifestyle | |||||||
Use of public transport | No | 20,843 | 3855 (18%) |
Ref.
| <10−4 |
Ref.
| <10−2 |
Yes | 3810 | 837 (22%) | 1.22 [1.12;1.34] | 1.17 [1.07;1.29] | |||
Pets at home | None | 13,492 | 2377 (17%) |
Ref.
| <10−4 |
Ref.
| <10− 4 |
At least one | 11,118 | 2311 (20%) | 1.21 [1.13;1.30] | 1.18 [1.09;1.27] | |||
Contacts with patients | No | 22,163 | 4154 (19%) |
Ref.
| 0.01 | NS | NS |
Yes | 2490 | 538 (22%) | 1.17 [1.04;1.30] | ||||
Contacts with elderly | No | 22,153 | 4234 (19%) |
Ref.
| 0.41 | – | – |
Yes | 2496 | 458 (18%) | 0.96 [0.86;1.07] | ||||
Contacts with a group of people | No | 16,795 | 3047 (18%) |
Ref.
| <10−4 | NS | NS |
Yes | 7858 | 1645 (21%) | 1.17 [1.09;1.25] | ||||
Contacts with children | No | 18,722 | 3342 (18%) |
Ref.
| <10−4 | NS | NS |
Yes | 5931 | 1350 (23%) | 1.33 [1.23;1.43] | ||||
Health characteristics | |||||||
Influenza vaccination (current season) | No | 16,083 | 3240 (20%) |
Ref.
| <10−4 |
Ref.
| 0.04 |
Yes | 8554 | 1450 (17%) | 0.82 [0.76;0.88] | 0.91 [0.84;0.99] | |||
Influenza vaccination (last season) | No | 15,190 | 3083 (20%) |
Ref.
| <10−4 | NS | NS |
Yes | 9305 | 1575 (17%) | 0.81 [0.75;0.87] | ||||
Smoking status | Non smoker | 21,995 | 4176 (19%) |
Ref.
| 0.55 | – | – |
Smoker | 2630 | 514 (20%) | 1.04 [0.92;1.16] | ||||
Chronic treatment for at least one comorbidityc | No comorbidity | 19,425 | 3648 (19%) |
Ref.
|
Ref.
| <10−3 | |
At least one comorbidity | 5228 | 1044 (20%) | 1.08 [0.99;1.17] | 0.10 | 1.20 [1.09;1.32] | ||
Asthma | 1449 | 384 (27%) | 1.53 [1.33;1.75] | < 10−4 | |||
Diabetes | 941 | 156 (17%) | 0.85 [0.70;1.04] | 0.12 | |||
Heart diseases | 2473 | 420 (17%) | 0.88 [0.78;0.99] | 0.03 | |||
Kidney diseases | 152 | 24 (16%) | 0.77 [0.48;1.25] | 0.29 | |||
Immunosuppression | 655 | 140 (21%) | 1.13 [0.91;1.39] | 0.26 | |||
Pulmonary diseases | 635 | 161 (25%) | 1.40 [1.13;1.73] | <10−2 | |||
Respiratory allergy | None | 16,400 | 2887 (18%) |
Ref.
| <10−4 |
Ref.
| <10−4 |
At least one | 8253 | 1805 (22%) | 1.29 [1.20;1.39] | 1.27 [1.18;1.37] | |||
BMI | Normal weight [18.5;25[ | 14,000 | 2563 (18%) |
Ref.
| <10−2 |
Ref.
| <10−4 |
Underweight < 18.5 | 1053 | 201 (19%) | 1.04 [0.88;1.25] | 0.92 [0.77;1.11] | |||
Overweight [25;30[ | 6571 | 1241 (19%) | 1.04 [0.96;1.13] | 1.18 [1.08;1.29] | |||
Obese ≥30 | 2629 | 586 (22%) | 1.26 [1.12;1.40] | 1.28 [1.14;1.44] |