Table 3 Effect of HPV vaccine chatbot intervention on primary and secondary outcomes

From: A vaccine chatbot intervention for parents to improve HPV vaccination uptake among middle school girls: a cluster randomized trial

  

Pre-intervention

Post-intervention

Post–pre difference (95% CI)

Adjusted RR (95% CI)

Coefficient (95% CI)

P value

HPV vaccine receipt or scheduled appointment among female students, n (%)

Chatbot

–

92 (7.1)

7.1 (5.7 to 8.5)

3.85 (2.48 to 5.97)

 

<0.001

Usual care

–

25 (1.8)

1.8 (1.1 to 2.5)

HPV vaccination-specific consultation, n (%)

Chatbot

–

635 (49.1)

49.1 (46.3 to 51.8)

2.73 (2.41 to 3.09)

 

<0.001

Usual care

–

242 (17.6)

17.6 (15.6 to 19.7)

Parental willingness to vaccinate their daughter, n (%)a

Chatbot

961 (74.3)

917 (70.9)

−3.4 (−6.8 to 0.0)

1.02 (0.98 to 1.07)

 

0.325

Usual care

993 (72.1)

937 (68.1)

−4.1 (−7.5 to −0.7)

High vaccine confidence, n (%)b

Chatbot

794 (61.4)

860 (66.5)

5.1 (1.4 to 8.8)

1.02 (0.97 to 1.08)

 

0.375

Usual care

796 (57.8)

830 (60.3)

2.5 (−1.2 to 6.1)

HPV-related literacy, mean (s.d.)

Chatbot

6.3 (3.1)

7.1 (2.8)

0.7 (0.5 to 1.0)

 

0.70 (0.52 to 0.88)

<0.001

Usual care

6.1 (3.2)

6.2 (3.1)

<0.1 (−0.2 to 0.3)

HPV-related literacy—knowledge, mean (s.d.)

Chatbot

3.9 (2.0)

4.3 (1.9)

0.5 (0.31 to 0.61)

 

0.38 (0.26 to 0.50)

<0.001

Usual care

3.7 (2.0)

3.8 (2.0)

0.1 (−0.1 to 0.2)

HPV-related literacy—rumor screening, mean (s.d.)

Chatbot

2.5 (1.5)

2.7 (1.4)

0.3 (0.2 to 0.4)

 

0.32 (0.21 to 0.43)

<0.001

Usual care

2.4 (1.5)

2.4 (1.5)

<−0.1 (−0.2 to 0.1)

  1. The analysis included 2,671 participants (1,294 in the chatbot group, 1,377 in the usual care group). Post–pre difference indicates the change from pre-intervention to post-intervention. GEEs were used for categorical outcomes and mixed-effects models for continuous outcomes, with class as the cluster unit and adjusting for stratification variables and baseline characteristics. Adjusted relative risks (RR) and coefficients represent the intervention effects assessed through interaction terms between intervention group and time, with P value as the statistical significance.
  2. aParental willingness was defined as parents who were ‘strongly willing’ or ‘willing’ to vaccinate their daughter against HPV. Parents who reported in the follow-up survey that they had scheduled an appointment or their daughter had been vaccinated were also categorized as ‘strongly willing’.
  3. bParents who ‘strongly agree’ or ‘agree’ with statements regarding the importance, efficacy, and safety of HPV vaccine, demonstrate high vaccine confidence.
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