Conceived and designed the experiments: MS. Performed the experiments: MS. Analyzed the data: RF SC. Contributed reagents/materials/analysis tools: MS RF YO JPM. Wrote the paper: MS JPM.
The authors have declared that no competing interests exist.
In July 2009, French public health authorities embarked in a mass vaccination campaign against A/H1N1 2009 pandemic-influenza. We explored the attitudes and behaviors of the general population toward pandemic vaccination.
We conducted a cross-sectional online survey among 2,253 French representative adults aged 18 to 64 from November 17 to 25, 2009 (completion rate: 93.8%). The main outcome was the acceptability of A/H1N1 vaccination as defined by previous receipt or intention to get vaccinated (“Yes, certainly”, “Yes, probably”). Overall 17.0% (CI 95%, 15.5% to 18.7%) of respondents accepted A/H1N1 vaccination. Independent factors associated with acceptability included: male sex (p = .0001); older age (p = .002); highest or lowest level of education (p = .016); non-clerical occupation (p = .011); having only one child (p = .008); and having received seasonal flu vaccination in prior 3 years (p<.0001). Acceptability was also significantly higher among pregnant women (37.9%) and other at risk groups with chronic diseases (34.8%) (p = .002). Only 35.5% of respondents perceived A/H1N1 influenza illness as a severe disease and 12.7% had experienced A/H1N1 cases in their close relationships with higher acceptability (p<.0001 and p = .006, respectively). In comparison to 26.0% respondents who did not consult their primary care physician, acceptability was significantly higher among 8.0% respondents who were formally advised to get vaccinated, and lower among 63.7% respondents who were not advised to get vaccinated (respectively: 15.8%, 59.5% and 11.7%- p<.0001). Among respondents who refused vaccination, 71.2% expressed concerns about vaccine safety.
Our survey occurred one week before the peak of the pandemic in France. We found that alarming public health messages aiming at increasing the perception of risk severity were counteracted by daily personal experience which did not confirm the threat, while vaccine safety was a major issue. This dissonance may have been amplified by having not involved primary care physicians in the mass vaccination campaign.
Following the recommendations of the World Health Organization
On October 20, 2009, the distribution of available vaccine supply started in hospitals for 1.2 million health care professionals including doctors and nurses of primary care settings
It is a well-established fact that risk perceptions influence influenza vaccine uptake
The survey was approved by the National Data Protection Authority (Commission Nationale Informatique et Libertés/CNIL) which is in charge of ethical issues and protection of individual data collection in France, and written informed consent was obtained from each participant.
A sample was randomly selected from an online research panel of more than 220,000 nationally representative households of the French general population developed and maintained by IPSOS Interactive Services (Gentilly, France), a survey research firm (
The online questionnaire used an adaptative questioning to reduce the number of questions with one question per screen
Respondents were then asked if they had an episode of flu since May 2009, and two questions allowed to determine the extent to which these episodes could be related to the A/H1N1 2009 influenza virus (as confirmed by a lab test in ambulatory medicine or by a hospitalization). Three additional questions asked whether respondents know personally someone who contracted A/H1N1 flu (family members, work colleagues, neighborhood and community).
Behaviors and attitudes toward A/H1N1 vaccination were assessed using three successive questions. First, respondents were asked if they had already been vaccinated (yes/no). All those who had not been vaccinated were subsequently asked if they were willing to get vaccinated using a 4-point scale (“Yes, certainly”, “Yes, probably”, “No, probably not”, “No, certainly not”). Finally, the main reasons for getting vaccinated or not were asked with two alternative multiple choices questions
Four questions dealt with respondents' risk perceptions of the threat associated with the A/H1N1 influenza-pandemic: two questions asked respondents whether they were “not at all worried”, “somewhat worried”, “worried” or “very worried” about the A/H1N1 influenza-pandemic for themselves or their close relatives; another question asked if the respondent personally felt at “higher risk”, “same risk”, “lower risk than average” or “not at all at risk” to contract A/H1N1 influenza infection; finally, respondents were asked if they estimated that A/H1N1 influenza-pandemic illness should be considered a “severe disease” (“not at all severe”, “somewhat severe”, “severe”, “very severe”).
Order response bias from subjective assessment was controlled by random allocation of: the direction of all ordinal scales like the ones just mentioned; and the two sections of questions addressing attitudes and behaviors on the one hand, and risk perceptions on the other hand. In addition, participants had unlimited time to complete the survey.
Finally, we used external data collected regularly on the panelists and made available for the present analysis by courtesy of IPSOS Interactive Services. IPSOS panel data were used to cross-validate the 6 stratification variables as well as self-declared health status, including pregnancy and the presence of chronic diseases.
The main outcome was the acceptability of A/H1N1 vaccination as defined by previous receipt or intention to get vaccinated (“Yes, certainly”, “Yes, probably”) versus unwillingness to get vaccinated (“No, probably not”, “No, certainly not”). Univariate analyses were carried out using chi-square tests. For ordinal variables, the Cochran-Armitage test for trend was performed. Multivariate logistic regression was carried out with acceptability of A/H1N1 vaccination as the dependent variable. All variables significant at p<.15 in univariate analyses were introduced in the initial multivariate model. If several variables were strongly linked, then all could be considered as “proxies” of the same phenomenon (i.e. risk perception, level of compliance with vaccination), and a single variable was selected to avoid problems of multicollinearity. All covariates were selected using a backward selection (p<.05 to stay). However, sample stratification variables (gender, age, occupation, household size, population in the area of location and region) were forced in the final model even if they did not meet the p<.05 criterion. Finally, we looked for additional two-way interaction effects using a backward selection (p<.05 to stay) on the final model augmented with all two-way interaction effects. All analyses were based on two-sided p values, with p<.05 considered to indicate statistical significance. All analyses were carried out using SAS 9.1.3 statistical software (SAS Institute, Cary, NC).
A total of 2,253 adults aged 18 to 64 completed the online survey between November 17 and 25, 2009 (completion rate = 93.8%). No differences for the six socio-demographic and geographic variables used for stratification were found between respondents and the French general population as observed in the latest census statistics
Overall, the acceptability of A/H1N1 vaccination was 17.0% (CI 95%, 15.5% to 18.7%). Only a minority (1.9% -n = 42) had already received the A/H1N1 pandemic vaccine (
Acceptance of A/H1N1 pandemic vaccination, N (%) | Total respondents (N = 2,167) | Univariate comparison (1)+(2) vs. (3) | Multivariate logistic model | ||||||||
Yes, N = 369 (17.0%) | No, N = 1,798 (83.0%) | (1)+(2) vs. (3) | |||||||||
(1) Already vaccinated, N = 42 (1.9%) | (2) Intention to get vaccinated, N = 327 (15.1%) | (3) No intention to get vaccinated | p-value |
Adjusted OR [CI 95%] |
p-value |
||||||
<.0001 | .0001 | ||||||||||
Male | 29 | (2.6) | 201 | (18.3) | 872 | (79.1) | 1,102 | (50.9) | Ref. | ||
Female | 13 | (1.2) | 126 | (11.8) | 926 | (87.0) | 1,065 | (49.1) | 0.57 [0.43; 0.76] | ||
<.0001 | .002 | ||||||||||
18-34 | 10 | (1.2) | 96 | (11.5) | 728 | (87.3) | 834 | (38.5) | Ref. | ||
35-54 | 19 | (1.9) | 163 | (16.3) | 820 | (81.8) | 1,002 | (46.2) | 1.41 [1.03; 1.93] | ||
≥55 | 13 | (3.9) | 68 | (20.6) | 250 | (75.5) | 331 | (15.3) | 2.11 [1.38; 3.24] | ||
.001 | .016 | ||||||||||
University graduates | 8 | (3.5) | 50 | (21.8) | 171 | (74.7) | 229 | (10.6) | Ref. | ||
High school graduates or college undergraduates | 19 | (1.5) | 163 | (12.8) | 1,094 | (85.7) | 1,276 | (58.9) | 0.53 [0.34; 0.82] | ||
Some high school | 14 | (2.4) | 100 | (16.8) | 480 | (80.8) | 594 | (27.4) | 0.69 [0.42; 1.13] | ||
Primary level of education | 1 | (1.5 ) | 14 | (20.6) | 53 | (77.9) | 68 | (3.1) | 0.87 [0.40; 1.92] | ||
.005 | .011 | ||||||||||
Clerical | 12 | (2.0) | 62 | (10.4) | 521 | (87.6) | 595 | (27.5) | Ref. | ||
Managerial | 5 | (1.8) | 56 | (20.1) | 218 | (78.1) | 279 | (12.9) | 2.14 [1.34; 3.41] | ||
Manual | 7 | (1.3) | 85 | (16.2) | 434 | (82.5) | 526 | (24.3) | 1.60 [1.07; 2.37] | ||
Self Employed | 1 | (0.8) | 22 | (19.0) | 93 | (80.2) | 116 | (5.3) | 2.18 [1.19; 3.99] | ||
Retired / Unemployed | 17 | (2.6) | 102 | (15.7) | 532 | (81.7) | 651 | (30.0) | 1.49 [1.01; 2.20] | ||
.84 | .85 | ||||||||||
One | 10 | (1.7) | 85 | (14.6) | 489 | (83.7) | 584 | (26.9) | Ref. | ||
Two | 23 | (2.0) | 174 | (15.3) | 938 | (82.7) | 1,135 | (52.4) | 1.00 [0.72; 1.37] | ||
More than two | 9 | (2.0) | 68 | (15.2) | 371 | (82.8) | 448 | (20.7) | 1.10[0.74; 1.63] | ||
.008 | .008 | ||||||||||
None | 20 | (1.7) | 152 | (13.4) | 965 | (84.9) | 1,137 | (52.5) | Ref. | ||
One | 15 | (3.2) | 85 | (18.3) | 364 | (78.5) | 464 | (21.4) | 1.68 [1.21; 2.35] | ||
More than one | 7 | (1.2) | 90 | (15.9) | 469 | (82.9) | 566 | (26.1) | 1.36 [0.96; 1.91] | ||
.12 | .044 | ||||||||||
< 20,000 inhabitants | 14 | (1.6) | 141 | (16.0) | 726 | (82.4) | 881 | (40.7) | Ref. | ||
[20,000 ; 100,000[ inhabitants | 4 | (1.4) | 36 | (12.6) | 246 | (86.0) | 286 | (13.2) | 0.61 [0.40; 0.95] | ||
[100,000 ; 200,000[ inhabitants | 6 | (4.8) | 23 | (18.6) | 95 | (76.6) | 124 | (5.7) | 1.46 [0.86; 2.50] | ||
≥ 200,000 inhabitants | 18 | (2.1) | 127 | (14.5) | 731 | (83.4) | 876 | (40.4) | 0.92 [0.68; 1.24] | ||
.35 | .18 | ||||||||||
Ile de France (includes Paris) | 7 | (1.7) | 55 | (13.2) | 354 | (85.1) | 416 | (19.2) | Ref. | ||
North-West | 14 | (2.9) | 81 | (16.6) | 393 | (80.5) | 488 | (22.5) | 1.57 [1.03; 2.39] | ||
North-East | 7 | (1.4) | 75 | (14.4) | 438 | (84.2) | 520 | (24.0) | 1.09 [0.72; 1.67] | ||
South-West | 2 | (0.9) | 34 | (15.3) | 186 | (83.8) | 222 | (10.3) | 0.99 [0.58; 1.70] | ||
South-East | 12 | (2.3) | 82 | (15.7) | 427 | (82.0) | 521 | (24.0) | 1.18 [0.78; 1.80] | ||
<.0001 | <.0001 | ||||||||||
Never | 10 | (0.6) | 188 | (11.1) | 1,500 | (88.3) | 1,698 | (78.4) | Ref. | ||
Yes, at least once | 32 | (6.8) | 139 | (29.6) | 298 | (63.6) | 469 | (21.6) | 3.21 [2.40; 4.29] | ||
.002 | .006 | ||||||||||
No | 27 | (1.7) | 238 | (15.2) | 1,302 | (83.1) | 1,567 | (72.3) | Ref. | ||
Yes, in close environment (family, working colleagues) | 13 | (4.7) | 51 | (18.6) | 210 | (76.7) | 274 | (12.7) | 1.65 [1.13; 2.41] | ||
Yes, outside close environment | 2 | (0.6) | 38 | (11.7) | 286 | (87.7) | 326 | (15.0) | 0.75 [0.49; 1.13] | ||
<.0001 | .002 | ||||||||||
No | 23 | (1.2) | 263 | (14.0) | 1,595 | (84.8) | 1,881 | (86.8) | Ref. | ||
Health care professionnal | 13 | (10.9) | 11 | (9.3) | 95 | (79.8) | 119 | (5.5) | 0.86 [0.48; 1.52] | ||
Pregnant women | 0 | 0 | 11 | (37.9) | 18 | (62.1) | 29 | (1.3) | 5.09 [1.86; 13.92] | ||
Other at-risk individuals with chronic diseases |
6 | (4.4) | 42 | (30.4) | 90 | (65.2) | 138 | (6.4) | 1.66 [1.05; 2.62] | ||
<.0001 | <.0001 | ||||||||||
Did not have any medical consultation | 5 | (0.9) | 84 | (14.9) | 474 | (84.2) | 563 | (26.0) | Ref. | ||
Positive advice by a primary care physician | 22 | (12.7) | 81 | (46.8) | 70 | (40.5) | 173 | (8.0) | 4.57 [2.92; 7.14] | ||
Positive advice by another health care professional | 4 | (7.8) | 11 | (21.6) | 36 | (70.6) | 51 | (2.3) | 1.99 [0.94; 4.18] | ||
No positive advice by a health care professionnal | 11 | (0.8) | 151 | (10.9) | 1,218 | (88.3) | 1,380 | (63.7) | 0.57 [0.42; 0.79] | ||
<.0001 | <.0001 | ||||||||||
Not at all severe or somewhat severe | 14 | (1.0) | 129 | (9.2) | 1,254 | (89.8) | 1,397 | (64.5) | Ref. | ||
Severe or very severe | 28 | (3.6) | 198 | (25.7) | 544 | (70.7) | 770 | (35.5) | 3.61 [2.76; 4.71] | ||
<.0001 | NS | ||||||||||
Poor or fair | 11 | (2.9) | 78 | (21.1) | 281 | (76.0) | 370 | (17.1) | |||
Good or very good or excellent | 31 | (1.7) | 249 | (13.9) | 1,517 | (84.4) | 1,797 | (82.9) |
*
†
‡
#
Main reason(s) for acceptability of pandemic vaccination (n = 369) | % [CI 95%] |
Protecting myself to avoid sickness | 74.5 [69.8; 78.9] |
Protecting my close relatives | 68.8 [63.8; 73.5] |
Getting vaccinated is convenient and quick | 27.4 [22.9; 32.2] |
A health professional advised me to get vaccinated | 25.2 [20.9; 30.0] |
Getting vaccinated is a civic duty | 24.1 [19.8; 28.8] |
Vaccination is recommended by public authorities | 23.6 [19.3; 28.3] |
Vaccination is free | 21.1 [17.1; 25.7] |
Protecting myself to avoid work absenteeism | 20.1 [16.1;24.5] |
Vaccines are safe | 9.2 [6.5; 12.6] |
Vaccines have no side effects | 7.1 [4.7; 10.2] |
Vaccines are not safe enough | 71.2 [69.0; 73.3] |
Vaccines have side effects | 68.4 [66.2; 70.1] |
Flu is not a severe disease | 19.7 [17.9; 21.7] |
Vaccines lack efficacy | 17.3 [15.6; 19.1] |
A health professional advised me to avoid vaccination | 15.3 [13.7; 17.0] |
I never get the flu | 15.0 [13.3; 16.7] |
I dislike the shots | 7.0 [5.8; 8.2] |
Getting vaccinated is inconvenient and too long | 3.6 [2.8; 4.6] |
I have medical reasons to avoid H1N1 vaccine | 1.4 [0.9; 2.1] |
Any items could be selected and thus proportions do not add to 100%. Items were presented in a random order.
Acceptability of A/H1N1 vaccination was significantly higher among pregnant women (37.9% -p = .003) and other at risk individuals with chronic diseases (34.8% -p<.001) as confirmed in multivariate analysis (
At time of the survey, the majority of the French general population did not associate A/H1N1 influenza-pandemic with a serious threat. Only one third of respondents (35.5%) considered A/H1N1 influenza-pandemic illness as a “severe” or “very severe” disease (
Respondents with a higher perception of the severity of influenza-pandemic illness were significantly more likely to accept vaccination, and this was confirmed after multivariate adjustment (
Respondents who had already been confronted to a case of A/H1N1 influenza-pandemic illness in their close relationships (family members and/or work colleagues) were more likely to accept A/H1N1 vaccination (
Respondents who were vaccinated for seasonal influenza at least once in the prior three years were also more likely to accept A/H1N1 vaccination (
Nearly three quarters of the population (74.0%) had consulted a physician at least once in the prior 6 months (
Although the deviance of the final model suggested that main effects fit very well the data (deviance = 1,481 with DF = 2,106; p = 1.00), we looked for additional two-way interaction effects using a backward selection. Two interactions effects were retained that contrasted acceptability of A/H1N1 pandemic vaccination for risk perception and seasonal influenza immunization depending on the number of children in the household: 1) respondents who considered A/H1N1 influenza-pandemic illness as a “severe” or “very severe” disease had adjusted odds-ratios for acceptability of vaccination of 2.56 (CI 95%, 1.74 to 3.76) for those having no child; 3.74 (CI 95%, 2.21 to 6.32) for those having one child; and 6.59 (CI 95%, 3.84 to 11.32) for those having more than one child (p = .020); and 2) respondents who were vaccinated for seasonal influenza at least once in the prior three years had adjusted odds-ratios for acceptability of vaccination of 4.67 (CI 95%, 3.25 to 6.99) for those having no child; 2.85 (CI 95%, 1.61 to 5.04) for those having one child; and 1.69 (CI 95%, 0.93 to 3.06) for those having more than one child (p = .016). The main effects of the final model remained significant when the two interaction effects were added with exception of the number of children in the household (p = .15).
This cross-sectional survey took place from November 17 to 25, 2009, shortly after the mass vaccination campaign had started in the general population (November 12), i.e. twelve weeks after the influenza-pandemic occurred in France and a week before the peak (November 23–29 – Week 48) as surveillance epidemiological data revealed subsequently
We found that risk perceptions of the A/H1N1 influenza-pandemic were strongly correlated to the acceptability of vaccination in the general population. It confirms findings from previous surveys conducted worldwide about attitudes and behaviors toward vaccination against seasonal flu
The substantial impact of other determinants illustrates that while the perceived severity of the A/H1N1 influenza-pandemic may be a sufficient condition for getting vaccinated in a mass vaccination campaign, it is not a necessary one. We found that individual characteristics including male gender, older age, and previous receipt of seasonal influenza vaccine were independent predictors of the acceptability of A/H1N1 pandemic vaccination. The same individual characteristics were similarly associated with the acceptability of A/H1N1 pandemic vaccination in other countries
However, we found that acceptability of A/H1N1 pandemic vaccination was as low as 17.0% among the French adult population, and concerns about A/H1N1 pandemic vaccine safety were the main reason quoted by 71.2% respondents who denied being vaccinated. In a Canadian qualitative study among health care professionals and the general public, the authors found that individuals were hesitant to accept pandemic vaccines and that “concerns about using new vaccines during a pandemic differ from concerns about using established products in non-crisis situations”
At time of the survey, the A/H1N1 influenza-pandemic had attracted massive media coverage in France, albeit in two opposite directions. On the one hand, the severity of A/H1N1 2009 influenza illness was stressed by daily reports of fatalities in the news media (i.e. 357 hospitalizations in intensive care units (ICUs) and 68 deaths at time of the survey)
Although the public's perception of a health risk usually increases with its coverage in the news media
As a consequence, 74% respondents looked for medical advice about A/H1N1 pandemic vaccination, an estimate above the expected number of consultations for a similar period
Finally, we found that parents had a higher acceptability of A/H1N1 pandemic vaccination for themselves than other adults without children. Further analysis showed that such higher acceptability was mediated by the perception of A/H1N1 influenza-pandemic illness as a “severe” or “very severe” disease with an increased acceptability depending on the number of children in the household. However, parents who denied vaccination for themselves expressed significantly more concerns about vaccine safety than other adults without children (76.5% vs. 66.6%, respectively; p<.0001). Quite logically, parents were reluctant to get their children vaccinated; only a quarter of parents accepted vaccination for their children but not for themselves. Future studies should address more specifically knowledge, attitudes and behaviors of parents about pandemic vaccination of their children since children are the most important drivers of influenza infection and may be targeted for pandemic vaccination before their parents
Our study is subject to a number of weaknesses. The advantage of our Web-based sampling strategy is the ability to quickly deploy a survey and thereby track responses in near real-time knowing that risk perceptions and attitudes toward pandemic vaccination may continuously evolve
Although we cannot unequivocally rule out the existence of selection bias in our online sample, our analyses are consistent with the view that our sample is representative of the French adult population aged 18 to 64 as compared to previous surveys conducted in random samples with use of traditional methods for data collection (face to face or phone interviews): 1) random sampling in our survey was stratified to match French official census statistics for gender, age, occupation, household size, size of the population in the area of residence, and region
Although such online survey shares with other survey methods the general limitations of results based on respondent's self-declarations, it is well established that self-administered questionnaires tend to yield fewer reports in the socially desirable direction than do interviewer-administered questionnaires, and a recent study suggested that online surveys may have the lowest social desirability bias
The uptake of A/H1N1 pandemic vaccines appears to be very low in France as compared to some other European Union and North American countries that have undertaken a mass vaccination campaign
We thank all individuals of the IPSOS panel who participated to the survey. We also thank Laila Idtaleb and Florentia Talento of IPSOS Interactive Services for their help getting the survey online so quickly. The authors thank Prof Catherine Leport, M.D., Ph.D. (Hôpital Bichat, AP-HP, Paris, France) for her advice on an earlier version of the manuscript. We are grateful to two anonymous reviewers for substantially improving the original manuscript. We also thank Dana Conley for her help with editing.