Introduction
Methods
Study sample and data collection
DCE attributes and levels
DCE attributes | Levels |
---|---|
Brand | Sinovac (level 1); BioNtech/Pfizer/Fosun (level 2).a |
Efficacy | 50% (level 1); 70% (level 2); 90% (level 3); |
Probability of serious adverse event | 1 in 10,000 (level 1); 1 in 100,000 (level 2) |
Vaccine uptake among acquaintances’ minor children | None received the vaccine (level 1); Some children in relative/friends’ family received the vaccine (level 2) |
Vaccination coverage among all children under 18 years | 20% (level 1); 40% (level 2); 60% (level 3) |
Recommendations from professionals | Recommended by the general physicians/pediatricians (level 1); Recommended by the expert panel of the government (level 2) |
Venue for vaccination | Community hall (level 1); Housing estate/school (level 2); Healthcare facilities (level 3) |
Gain/loss-framing of information and presentation of mortality information | |
Gain-frame + no mortality | If a child is vaccinated, he/she has around 1/2—1/20 probability of COVID-19 infection of un-vaccinated people |
Gain-frame + mortality | If a child is vaccinated, he/she has around 1/2—1/20 probability of COVID-19 infection of un-vaccinated people, and has around 1/7–1/30 risk of death of un-vaccinated people |
Loss-frame + no mortality | If a child is not vaccinated, he/she has around 2–20 times probability of COVID-19 infection of vaccinated people |
Loss-frame + mortality | If a child is not vaccinated, he/she has around 2–20 times probability of COVID-19 infection of vaccinated people, and has around 7–30 times risk of death of vaccinated people |
Experimental design
Hypothetical scenario (repeated at every choice task): a) Both Sinovac and BioNtech have been tested in scientific research that they can be used, and approved by the government, in children and adolescent under 18 years. Its efficacy and safety in children are the same as in adults. Vaccination for children under 18 years need to be consented by their parents. The vaccination is free-of-charge. They can get the vaccination with or without prior online reservation, and with or without company of the parents. The other vaccination procedures are the same as the adults b) Please note that: If a child is not vaccinated, he/she has around 2–20 times probability of COVID-19 infection of vaccinated people | |||
---|---|---|---|
Vaccination plan 1 | Vaccination plan 2 | No vaccination for 6 months | |
Brand | BioNTech/Pfizer/Fosun | Sinovac | No vaccination for 6 months: □ |
Efficacy * | 90% | 70% | |
Probability of serious adverse event * | 1 in 10,000 | 1 in 100,000 | |
Vaccine uptake among acquaintances’ minor children | Some children in relative/friends’ family received the vaccine | None received the vaccine | |
Vaccination coverage among all children under 18 years | 40% | 60% | |
Recommendations from professionals | Recommended by the general physicians/pediatricians | Recommended by the expert panel of the government | |
Venue for vaccination | Community hall | Healthcare facilities | |
*The above information is hypothetical and for research purposes only. For the actual details, please refer to the information provided by the Department of Health | |||
Which vaccination plan would you like to choose? | Vaccination plan 1: □ | Vaccination plan 2: □ |
Study questionnaire
Statistical analysis
Results
Respondent characteristics
Total | Parental vaccination intention1 | P values | |||||
---|---|---|---|---|---|---|---|
Not intended | Intended | ||||||
N | % | N | % | N | % | ||
Age of parents | |||||||
18–34 yrs | 82 | 27.5 | 12 | 40.0 | 70 | 26.1 | 0.163 |
35–49 yrs | 170 | 57.1 | 16 | 53.3 | 154 | 57.5 | |
50 + yrs | 46 | 15.4 | 2 | 6.7 | 44 | 16.4 | |
Sex | |||||||
Male | 114 | 38.3 | 7 | 23.3 | 107 | 39.9 | 0.076 |
Female | 184 | 61.7 | 23 | 76.7 | 161 | 60.1 | |
Education | |||||||
Below bachelor degree | 161 | 54.0 | 14 | 46.7 | 147 | 54.9 | 0.394 |
Bachelor degree or above | 137 | 46.0 | 16 | 53.3 | 121 | 45.2 | |
Household income | |||||||
Below HK$30,000 | 126 | 42.3 | 8 | 26.7 | 118 | 44.0 | 0.068 |
HK$30,000 + | 172 | 57.7 | 22 | 73.3 | 150 | 56.0 | |
Chronic conditions of parents | |||||||
No | 245 | 82.2 | 24 | 80.0 | 221 | 82.5 | 0.738 |
Yes | 53 | 17.8 | 6 | 20.0 | 47 | 17.5 | |
Parental uptake of COVID-19 vaccine | |||||||
No | 58 | 19.8 | 20 | 69.0 | 38 | 14.4 | < 0.001* |
Yes | 235 | 80.2 | 9 | 31.0 | 226 | 85.6 | |
(missing) | 5 | 1 | 4 | ||||
Perceived “likely/very likely” to be infected | |||||||
No | 188 | 63.1 | 21 | 70.0 | 167 | 62.3 | 0.408 |
Yes | 110 | 36.9 | 9 | 30.0 | 101 | 37.7 | |
Perceived “slightly severe/very severe” if get infected COVID-19 | |||||||
No | 143 | 48.0 | 19 | 63.3 | 124 | 46.3 | 0.076 |
Yes | 155 | 52.0 | 11 | 36.7 | 144 | 53.7 | |
“Slightly/very” worry about being quarantined | |||||||
No | 90 | 30.2 | 14 | 46.7 | 76 | 28.4 | 0.038* |
Yes | 208 | 69.8 | 16 | 53.3 | 192 | 71.6 | |
Age of children | |||||||
0–4 yrs | 78 | 26.2 | 13 | 43.3 | 65 | 24.3 | 0.024* |
5–11 yrs | 98 | 32.9 | 11 | 36.7 | 87 | 32.5 | |
12–17 yrs | 122 | 40.9 | 6 | 20.0 | 116 | 43.3 | |
Perceived the children “likely/very likely” to be infected | |||||||
No | 80 | 27.3 | 14 | 48.3 | 66 | 25.0 | 0.008* |
Yes | 213 | 72.7 | 15 | 51.7 | 198 | 75.0 | |
(missing) | 5 | 1 | 4 | ||||
Perceived effectiveness of the vaccine for children | |||||||
Low | 128 | 43.0 | 21 | 70.0 | 107 | 39.9 | 0.007* |
Medium | 119 | 39.9 | 6 | 20.0 | 113 | 42.2 | |
High | 51 | 17.1 | 3 | 10.0 | 48 | 17.9 | |
“Slightly/very” worry about vaccine side effect for children | |||||||
No | 77 | 26.3 | 3 | 10.3 | 74 | 28.0 | 0.040* |
Yes | 216 | 73.7 | 26 | 89.7 | 190 | 72.0 | |
(missing) | 5 | 1 | 4 | ||||
“Slightly/very” worry about missing school or work due to children’s infection | |||||||
No | 132 | 45.1 | 17 | 58.6 | 115 | 43.6 | 0.122 |
Yes | 161 | 55.0 | 12 | 41.4 | 149 | 56.4 | |
(missing) | 5 | 1 | 4 | ||||
Total | 298 | 100.0 | 30 | 100.0 | 268 | 100.0 |
Influence of DCE attributes and information framing on vaccination likelihood
Coefficient | 95%CI1 | ||
---|---|---|---|
Mean | |||
Brand (Sinovac as reference) | |||
BioNtech (β1) | 0.65** | (0.42, 0.89) | |
Efficacy (50% as reference) | |||
70% (β2) | 0.33* | (0.09, 0.56) | |
90% (β3) | 0.70** | (0.43, 0.97) | |
Serious adverse event (1/10,000 as reference) | |||
1/100,000 ppl (β4) | 0.37** | (0.16, 0.57) | |
Vaccine uptake among acquaintances’ minor children (None as reference) | |||
Some children received the vaccine (β5) | 0.08 | (−0.10, 0.26) | |
Vaccination coverage among all children under 18 years (20% as reference) | |||
40% (β6) | 0.33* | (0.11, 0.55) | |
60% (β7) | 0.39* | (0.13, 0.64) | |
Recommendations from professionals (government experts as reference) | |||
Physician/pediatricians (β8) | −0.01 | (−0.19, 0.18) | |
Venue for vaccination (community hall as reference) | |||
Housing estate/school (β9) | 0.00 | (−0.24, 0.25) | |
Healthcare facilities (β10) | 0.21 | (−0.03, 0.45) | |
Opt-in (ASC1, β0) | −4.70** | (−6.26, -3.13) | |
Loss frame x opt-in (βlossframe) | 1.04* | (0.07, 2.02) | |
Mortality x opt-in (βmortality) | 0.11 | (−0.80, 1.03) | |
5–11 years x opt-in (β5-11 yr) | 0.66 | (−0.25, 1.57) | |
12–17 years x opt-in (β12-17 yr) | 1.79** | (0.84, 2.75) | |
Parent uptake of vaccine x opt-in (βparent) | 1.71** | (0.85, 2.58) | |
Standard deviation | |||
Brand (Sinovac as reference) | |||
BioNtech | 1.80** | (1.54, 2.05) | |
Efficacy (50% as reference) | |||
70% | 0.89** | (1.19, 0.58) | |
90% | 1.19** | (0.89, 1.50) | |
Serious adverse event (1/10,000 as reference) | |||
1/100,000 ppl | 1.24** | (1.03, 1.45) | |
Vaccine uptake among acquaintances’ minor children (None as reference) | |||
Some children received the vaccine | 0.37* | (0.65, 0.10) | |
Vaccination coverage among all children under 18 years (20% as reference) | |||
40% | 0.40* | (0.17, 0.62) | |
60 | 1.07** | (0.78, 1.35) | |
Recommendations from professionals (government experts as reference) | |||
Physician/pediatricians | 0.45** | (0.23, 0.67) | |
Venue for vaccination (community hall as reference) | |||
Housing estate/school | 0.34 | (−0.02, 0.71) | |
Healthcare facilities | 0.14 | (−0.40, 0.67) |