ABSTRACT
BackgroundCOVID-19 vaccination has faced a range of challenges from supply-side barriers such as insufficient vaccine supply and negative information environment and demand-side barriers centring on public acceptance and confidence in vaccines. This study assessed global spatiotemporal trends in demand- and supply-side barriers to vaccine uptake using COVID-19-related social media data and explored the country-level determinants of vaccine acceptance. MethodsWe accessed a total of 13,093,406 tweets sent between November 2020 and March 2022 about the COVID-19 vaccine in 90 languages from 135 countries using Meltwater(R) (a social listening platform). Based on 8,125 manually-annotated tweets, we fine-tuned multilingual deep learning models to automatically annotate all 13,093,406 tweets. We present spatial and temporal trends in four key spheres: (1) COVID-19 vaccine acceptance; (2) confidence in COVID-19 vaccines; (3) the online information environment regarding the COVID-19 vaccine; and (4) perceived supply-side barriers to COVID-19 vaccination. Using univariate and multilevel regressions, we evaluated the association between COVID-19 vaccine acceptance on Twitter(R) and (1) country-level characteristics regarding governance, pandemic preparedness, trust, culture, social development, and population demographics; (2) country-level COVID-19 vaccine coverage; and (3) Google(R) search trends on adverse vaccine events. FindingsCOVID-19 vaccine acceptance was high among Twitter(R) users in Southeast Asian, Eastern Mediterranean, and Western Pacific countries, including India, Indonesia, and Pakistan. In contrast, acceptance was relatively low in high-income nations like South Korea, Japan, and the Netherlands. Spatial variations were correlated with country-level governance, pandemic preparedness, public trust, culture, social development, and demographic determinants. At the country level, vaccine acceptance sentiments expressed on Twitter(R) predicted higher vaccine coverage. We noted the declining trend of COVID-19 vaccine acceptance among global Twitter(R) users since March 2021, which was associated with increased searches for adverse vaccine events. Interpretation In future pandemics, new vaccines may face the potential low-level and declining trend in acceptance, like COVID-19 vaccines, and early responses are needed. Social media mining represents a promising surveillance approach to monitor vaccine acceptance and can be validated against real-world vaccine uptake data. FundingNational Natural Science Foundation of China.
ABSTRACT
BackgroundMultiple COVID-19 vaccines have now been licensed for human use, with other candidate vaccines in different stages of development. Effective and safe vaccines against COVID-19 are essential to achieve global control of the pandemic caused by severe acute respiratory coronavirus 2 (SARS-CoV-2), but multiple factors, including vaccine supply and vaccine confidence, will be key for high rates of global uptake. Confidence in COVID-19 vaccines, socio-demographic status, and recent emotional status are likely to be key drivers of COVID-19 vaccine acceptance. In this study, we explore these determinants of COVID-19 vaccination intent across17 countries worldwide. MethodsIn this large-scale multi-country study, we explore intent to accept a COVID-19 vaccine and the socio-demographic and emotional determinants of uptake for 17 countries and over 19,000 individuals surveyed in June and July 2020 via nationally representative samples. We used Bayesian ordinal logistic regressions to probe the relationship between intent to accept a COVID-19 vaccine and individuals socio-demographic status, their confidence in COVID-19 vaccines, and their recent emotional status. Gibbs sampling was used for Bayesian model inference, with 95% Bayesian highest posterior density intervals used to capture uncertainty. FindingsIntent to accept a COVID-19 vaccine is highest in India, where 77.8% (95% HPD, 75.5 to 80.0%) of respondents strongly agreeing that they would take a new COVID-19 vaccine if it were available. The Democratic Republic of Congo (15.5%, 12.2 to 18.6%) and France (26.4%, 23.7 to 29.2%) have the lowest share of respondents who strongly agree that they would accept a COVID-19. Confidence in the safety, importance, and effectiveness of COVID-19 vaccines are the most widely informative determinants of vaccination intent. Socio-demographic and emotional determinants played a lesser role, with being male and having higher education was associated with increased uptake intent in five countries and being fearful of catching COVID-19 also a strong determinant of uptake intent. InterpretationBarriers to COVID-19 vaccine acceptance will be highly country and context dependent. These findings highlight the importance of regular monitoring of COVID-19 vaccine confidence to identify groups less likely to vaccinate and to monitor the impact of vaccination policies on uptake behaviour.
ABSTRACT
BackgroundFour vaccines against the novel coronavirus 2019 disease (COVID-19) caused by the severe acute respiratory coronavirus 2 (SARS-CoV-2) have currently been approved for use in the United Kingdom. As of 30 April 2021, over 34 million adults have received at least one dose of a COVID-19 vaccine. The UK Government is considering the introduction of vaccine passports for domestic use and to facilitate international travel for UK residents. Although vaccine incentivisation has been cited as a motivating factor for vaccine passports, it is currently unclear whether vaccine passports are likely to increase inclination to accept a COVID-19 vaccine. MethodsWe conducted a large-scale national survey in the UK of 17,611 adults between 9 and 27 April 2021. Bayesian multilevel regression and poststratification is used to provide unbiased national-level estimates of the impact of the introduction of vaccine passports on inclination to accept COVID-19 vaccines among all respondents who have not yet had two vaccination doses. Multilevel regressions identify the differential impact of the likely impact of vaccine passports on uptake intent between socio-demographic groups. Gibbs sampling was used for Bayesian model inference, with 95% highest posterior density intervals used to capture uncertainty in all parameter estimates. FindingsWe find that the introduction of vaccine passports will likely lower inclination to accept a COVID-19 vaccine once baseline vaccination intent has been adjusted for. Notably, this decrease is larger if passports were required for domestic use rather than for facilitating international travel. The impact of passports while controlling for baseline vaccination intent differentially impacts individuals by socio-demographic status, with being male (OR 0{middle dot}87, 0{middle dot}76 to 0{middle dot}99) and having degree qualifications (OR 0{middle dot}84, 0{middle dot}72 to 0{middle dot}94) associated with a decreased inclination to vaccinate if passports were required for domestic use, while Christians (OR 1{middle dot}23, 1{middle dot}08 to 1{middle dot}41) have an increased inclination over atheists or agnostics. There is a strong association between change in vaccination inclination if passports were introduced and baseline vaccination intent: stated change in vaccination inclination is thus lower among Black or Black British respondents (compared to Whites), younger age groups, and non-English speakers. We find notable sub-national trends, for example, that passports could increase inclination among students and Jewish respondents in London compared to those in full-time education or atheists or agnostics, respectively. InterpretationTo our knowledge, this is the first quantitative assessment of the potential impact of the introduction of vaccine passports on COVID-19 vaccine intention. Our findings should be interpreted in light of sub-national trends in current uptake rates across the UK, as our results suggest that vaccine passports may induce a lower vaccination inclination in socio-demographic groups that cluster geographically in large urban areas. Caution should therefore be exercised in introducing passports as they may result in less positive health-seeking behaviours for the COVID-19 vaccine (as well as other existing or future vaccinations) and may contribute to concentrated areas of low vaccinate uptake, which is an epidemic risk. We call for further evidence on the impact of vaccine certification on confidence in COVID-19 vaccines and in routine immunisations in wider global settings and, in particular, in countries with low overall trust in vaccinations or in authorities that administer or recommend vaccines. FundingThis survey was funded by the Merck Investigator Studies Program (MISP) Research in contextO_ST_ABSEvidence before this studyC_ST_ABSProof of vaccination has, to date, had limited use in public and private settings for the UK public, such as proof of yellow fever vaccination for international travel to limited destinations, or requirements of Hepatitis B vaccination in some medical roles. Although recent surveys have suggested that the majority of the British public support vaccine passports, we are not aware of any studies assessing the impact that proof of vaccination status for domestic use or for international travel may have on vaccination inclination and thus--perhaps more importantly--on epidemic spread. Added value of this studyWe conducted a large-scale survey of more than 17,000 members of the UK public to explore attitudes to vaccine passports for domestic and international use. Bayesian methods are used to compute nationally representative estimates of the impact of vaccine passports on change in inclination to accept COVID-19 vaccines and to establish the socio-demographic determinants of vaccination inclination. This study is, as far as we are aware, the first to assess the impact of vaccine passports on vaccination inclination in the UK. Implications of all the possible evidenceThis study provides novel insights into the potential impact of vaccine passports on COVID-19 vaccine intent in the UK. Although we find that vaccine passports receive popular support in the UK, there exists large variations in their appeal that stratify along socio-demographic lines. Most notably, younger age groups, Black and Black British ethnicities (compared to Whites), and non-English speakers are more likely to express a lower inclination to vaccinate if passports were introduced. Although these groups comprise a relatively small proportion of the UK population, there are crucial issues that these perceptions among these groups cause: notably, that these groups tend to have lower baseline vaccination intent and they cluster geographically. Therefore, since geographic clusters of low vaccination uptake can result in disproportionate increases in required vaccination levels for herd immunity in adjacent settings, we need to exercise extreme caution in public health interventions that may push these areas further away from vaccination. This is especially so if such an intervention will have little overall impact on the majority of the population outside these areas who are already quite willing to vaccinate. Overall, we find that the introduction of passports for either domestic or international use has a net negative impact on vaccination inclination, once we control for baseline vaccination intent. Our findings suggest that vaccination passports may not only yield damaging health outcomes for already marginalised communities: this may lead to further distrust in the government and public health systems and may have negative downstream consequences for other health-seeking behaviours, for example, routine immunisations.
ABSTRACT
BackgroundThis study developed deep learning models to monitor global intention and confidence of Covid-19 vaccination in real time. MethodsWe collected 6.73 million English tweets regarding Covid-19 vaccination globally from January 2020 to February 2021. Fine-tuned Transformer-based deep learning models were used to classify tweets in real time as they relate to Covid-19 vaccination intention and confidence. Temporal and spatial trends were performed to map the global prevalence of Covid-19 vaccination intention and confidence, and public engagement on social media was analyzed. FindingsGlobally, the proportion of tweets indicating intent to accept Covid-19 vaccination declined from 64.49% on March to 39.54% on September 2020, and then began to recover, reaching 52.56% in early 2021. This recovery in vaccine acceptance was largely driven by the US and European region, whereas other regions experienced the declining trends in 2020. Intent to accept and confidence of Covid-19 vaccination were relatively high in South-East Asia, Eastern Mediterranean, and Western Pacific regions, but low in American, European, and African regions. 12.71% tweets expressed misinformation or rumors in South Korea, 14.04% expressed distrust in government in the US, and 16.16% expressed Covid-19 vaccine being unsafe in Greece, ranking first globally. Negative tweets, especially misinformation or rumors, were more engaged by twitters with fewer followers than positive tweets. InterpretationThis global real-time surveillance study highlights the importance of deep learning based social media monitoring to detect emerging trends of Covid-19 vaccination intention and confidence to inform timely interventions. FundingNational Natural Science Foundation of China. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSWith COVID-19 vaccine rollout, each country should investigate its vaccination intention in local contexts to ensure massive vaccination. We searched PubMed for all articles/preprints until April 9, 2021 with the keywords "("Covid-19 vaccines"[Mesh] OR Covid-19 vaccin*[TI]) AND (confidence[TI] OR hesitancy[TI] OR acceptance[TI] OR intention[TI])". We identified more than 100 studies, most of which are country-level cross-sectional surveys, and the largest global survey of Covid-19 vaccine acceptance only covered 32 countries to date. However, how Covid-19 vaccination intention changes over time remain unknown, and many countries are not covered in previous surveys yet. A few studies assessed public sentiments towards Covid-19 vaccination using social media data, but only targeting limited geographical areas. There is a lack of real-time surveillance, and no study to date has globally monitored Covid-19 vaccination intention in real time. Added value of this studyTo our knowledge, this is the largest global monitoring study of Covid-19 vaccination intention and confidence with social media data in over 100 countries from the beginning of the pandemic to February 2021. This study developed deep learning models by fine-tuning a Bidirectional Encoder Representation from Transformer (BERT)-based model with 8000 manually-classified tweets, which can be used to monitor Covid-19 vaccination beliefs using social media data in real time. It achieves temporal and spatial analyses of the evolving beliefs to Covid-19 vaccines across the world, and also an insight for many countries not yet covered in previous surveys. This study highlights that the intention to accept Covid-19 vaccination have experienced a declining trend since the beginning of the pandemic in all world regions, with some regions recovering recently, though not to their original levels. This recovery was largely driven by the US and European region (EUR), whereas other regions experienced the declining trends in 2020. Intention to accept and confidence of Covid-19 vaccination were relatively high in South-East Asia region (SEAR), Eastern Mediterranean region (EMR), and Western Pacific region (WPR), but low in American region (AMR), EUR, and African region (AFR). Many AFR countries worried more about vaccine effectiveness, while EUR, AMR, and WPR concerned more about vaccine safety (the most concerns with 16.16% in Greece). Online misinformation or rumors were widespread in AMR, EUR, and South Korea (12.71%, ranks first globally), and distrust in government was more prevalent in AMR (14.04% in the US, ranks first globally). Our findings can be used as a reference point for survey data on a single country in the future, and inform timely and specific interventions for each country to address Covid-19 vaccine hesitancy. Implications of all the available evidenceThis global real-time surveillance study highlights the importance of deep learning based social media monitoring as a quick and effective method for detecting emerging trends of Covid-19 vaccination intention and confidence to inform timely interventions, especially in settings with limited sources and urgent timelines. Future research should build multilingual deep learning models and monitor Covid-19 vaccination intention and confidence in real time with data from multiple social media platforms.
ABSTRACT
The rollout of COVID-19 vaccines has begun to at-risk populations around the world. It is currently unclear whether rejection of the vaccine will pose challenges for achieving herd/community immunity either through large-scale rejection or localised pockets. Here we predict uptake of the vaccine at unprecedented spatial resolution across the UK using a large-scale survey of over 17,000 individuals. Although the majority of the UK population would likely take the vaccine, there is substantial heterogeneity in uptake intent across the UK. Large urban areas, including London and North West England, females, Black or Black British ethnicities, and Polish-speakers are among the least accepting. This study helps identify areas and socio-demographic groups where vaccination levels may not reach those levels required for herd immunity. Identifying clusters of non-vaccinators is extremely important in the context of achieving herd immunity as vaccination "cold-spots" can amplify epidemic spread and disproportionately increase vaccination levels required for herd protection.
ABSTRACT
The successful development and widespread acceptance of a SARS-CoV-2 vaccine will be a major step in fighting the pandemic, yet obtaining high uptake will be a challenging task, worsened by online misinformation. To help inform successful COVID-19 vaccination campaigns in the UK and US, we conducted a survey to quantify how online misinformation impacts COVID-19 vaccine uptake intent and identify socio-economic groups that are most at-risk of non-vaccination and most susceptible to online misinformation. Here, we report findings from nationally representative surveys in the UK and the US conducted in September 2020. We show that recent misinformation around a COVID-19 vaccine induces a fall in vaccination intent among those who would otherwise "definitely" vaccinate by 6.4 (3.8, 9.0) percentages points in the UK and 2.4 (0.1, 5.0) in the US, with larger decreases found in intent to vaccinate to protect others. We find evidence that socio-econo-demographic, political, and trust factors are associated with low intent to vaccinate and susceptibility to misinformation: notably, older age groups in the US are more susceptible to misinformation. We find evidence that scientific-sounding misinformation relating to COVID-19 and vaccines COVID-19 vaccine misinformation lowers vaccination intent, while corresponding factual information does not. These findings reveal how recent COVID-19 misinformation can impact vaccination rates and suggest pathways to robust messaging campaigns.
