Study population
Demographic characteristics of the study population are described in Table 1. In brief, the U.S. respondents were evenly divided across all eight waves of survey collection while each of the remaining five sites were evenly divided across four waves of survey collection. In total there were 22,870 participants included in the study, with over 630 in each wave of data collection. Details of the initial sample size, the number who agreed to informed consent, and the number who finished the survey are available elsewhere (Table A at https://doi.org/10.6084/m9.figshare.14792058).
Among the U.S. survey respondents, 17% reported having been diagnosed with COVID-19 and 44% experienced a friend or family member with COVID-19. This is contrast to participants in mainland China, Taiwan, and Malaysia who reported lower experiences with COVID-19 both personally and among friends and family. However, 40% of survey respondents in Indonesia and 37% of respondents in India reported a diagnosis of COVID-19. Forty-four percent of respondents in Indonesia and 70% of respondents in India reported experiencing a friend or family member being diagnosed with COVID-19. Across all six country sites, a large proportion of respondents reporting experiencing a case of COVID-19 in the media.
[Figure 1]
Associations between experiences with COVID-19 and intention to vaccinate
Overall, intent to vaccinate was lowest in the US and Taiwan, and highest in India, Indonesia, and China, with Malaysia being in the middle. In general, we found higher risk perceptions were associated with higher vaccination intent. Figure 1 shows the average vaccination intent by quantile in the total sample and within each country in 2020. For example, in the lowest decile of perceived susceptibility – which was 0% perceived susceptibility, 69% (95% CI: 54%, 84%) would accept a COVID-19 vaccine, but in the highest decile of perceived susceptibility (ranging from 86% to 99% susceptibility), 93% would accept a vaccine (95% CI: 84%, 100%). Similar patterns were found for perceived risk of dying. The lowest decile of perceived risk of dying (0%) had a vaccine acceptance of 67% (95% CI: 51%, 83%). In the highest decile (where perceived risk of dying ranged from 92% to 100%), vaccine acceptance was 91% (95% CI: 81%, 100%). For both figures there was a general monotonic relationship between increasing quantiles of risk perception and greater vaccination intent, with some wobbliness at certain key percentages: e.g., there were dips around 10% and 50%.
[Table 2]
Table 2 shows the associations between all three experiences with COVID-19 and vaccination intent using logistic regression models. By and large, reporting having been personally diagnosed with COVID-19 had the greatest impact on vaccination intent across country sites compared to experiencing a friend or family member diagnosed with COVID-19 or media experiences. For example, in India participants that reported a personal diagnosis with COVID-19 had 12.95 times the odds (95% CI: 4.89, 34.28) of reporting they would accept a COVID-19 vaccine compared to those who were not personally diagnosed with COVID-19. In the US, having had a personal diagnosis of COVID-19 was associated with 1.84 times the odds (95% CI: 1.29, 2.62) of accepting a vaccine compared to those who were not personally diagnosed with COVID-19.
Additionally, experiencing a COVID-19 case in the media, particularly a severe case, was associated with increased odds of accepting a vaccine in the US, Taiwan, Malaysia, Indonesia, and India. The association was strongest among participants in Indonesia: those who experienced a severe case of COVID-19 in the media had 3.11 times the odds (95% CI: 1.53, 6.31) of accepting a vaccine compared to those who had not experienced a case of COVID-19 in the media. Experiencing a friend or family member with COVID-19 was not associated with increased odds of vaccination acceptance across country sites.
Associations between experiences with COVID-19 and perceived susceptibility to COVID-19 and COVID-19-related mortality
[Table 3]
Marginal outcomes from linear regression models of risk perceptions are shown in Table 3. All three experiences were significantly associated with perceived susceptibility in the US. The mean perceived susceptibility was lowest among those with no previous diagnosis (32%) and highest in those with a very severe case of COVID-19 (56%) (P=0.0034). Similarly, knowing friends/family diagnosed with a severe case of COVID-19 led to the highest perceived susceptibility (50%), and was lower among those who knew a non-severe case (42%), or among those who did not know a case (38%) (P=0.0019). Interestingly, in the US experiencing a non-severe case of COVID-19 in the media resulted in the lowest perceived risk of susceptibility to COVID-19 (40%) compared to not experiencing a case of COVID-19 in the media (44%) or experiencing a severe case of COVID-19 in the media (47%) (P=0.0224).
In the US, a similar pattern of results was observed examining perceived risk of dying of COVID-19. Experiences with COVID-19 (individual diagnosis, friends/family, and media) were associated with increased perceived risk of dying. Again, experiencing a non-severe case of COVID-19 in the media was associated with the lowest perceived risk of dying of COVID-19 (39%) compared to not experiencing a case in the media (47%) or experiencing a severe case in the media (52%) (P<0.0001).
In mainland China, only individuals personal experience with a COVID-19 diagnosis was associated with an increase in one’s perceived susceptibility to COVID-19 (P = 0.0252). However, having a friend or family member diagnosed with COVID-19 significantly impacted perceived risk of dying from COVID-19 in mainland China (P=0.0124).
In Taiwan, those that reported having been diagnosed with COVID-19 had a greater perceived risk of dying from COVID-19 (46% for those with a non-severe case and 54% for those with a severe case) compared to those who were never diagnosed with COVID-19 (31%) (P=0.0452).
For respondents in India, experiencing a case of COVID-19 in the media was significantly associated with increased perceived susceptibility to COVID-19. Those that never experienced a case in the media had a 39% perceived susceptibility compared to experiencing a non-severe case (44% perceived susceptibility) and those experiencing a severe case (51% perceived susceptibility) (P=0.0098).
For respondents in Malaysia and Indonesia, there were not significant associations between experiences with COVID-19 and perceived risk of susceptibility to or mortality related to COVID-19.
Mediation of the experiences – vaccine intent relationship by risk perceptions
[Table 4]
Table 4 shows models with and without perceived susceptibility, showing the direct and total estimated effect of media experiences on vaccination outcomes. Pre-vaccine rollout, each additional increase in perceived susceptibility was associated with 1.02 times higher odds of vaccination intent (95% CI: 1.02, 1.02). Media experiences were still significant, but slightly attenuated (OR: 1.56, 95% CI: 1.40, 1.75), corresponding to a proportion mediated of 25% (95% CI: 18%, 31%, P<0.0001). In 2021, post-vaccine rollout, there were similar directions of association, and the proportion mediated came to 16% (95% CI: 12%, 19%, P<0.0001).