Vaccine Take-up Research Articles

Using double-debiased machine learning to estimate the impact of Covid-19 vaccination on mortality and staff absences in elderly care homes.

Machine learning approaches provide an alternative to traditional fixed effects estimators in causal inference. In particular, double-debiased machine learning (DDML) can control for confounders without making subjective judgements about appropriate functional forms. In this paper, we use DDML to examine the impact of differential Covid-19 vaccination rates on care home mortality and other outcomes. Our approach accommodates fixed effects to account for unobserved heterogeneity. In contrast to standard fixed effects estimates, the DDML results provide some evidence that higher vaccination take-up amongst residents, but not staff, reduced Covid mortality in elderly care homes. However, this effect was relatively small, is not robust to alternative measures of mortality and was restricted to the initial vaccination roll-out period.

Key Determinants of COVID-19 Vaccination Take-Up in Remote Rural Areas: Evidence From Colombia

Key Determinants of COVID-19 Vaccination Take-Up in Remote Rural Areas: Evidence From Colombia

Risk compensation after COVID-19 vaccination: Evidence from vaccine rollout by exact birth date in South Korea.

We utilize the phased rollout of COVID-19 vaccines by exact birth date in South Korea as a natural experiment for testing risk compensation. People may resume face-to-face social activities following vaccination because they perceive lower risk of infection. Applying a regression discontinuity design based on birth date cutoffs for vaccine eligibility, we find no evidence of risk-compensating behaviors, as measured by large, high-frequency data from credit card and airline companies as well as survey data. We find some evidence of self-selection into vaccine take-up based on perception toward vaccine effectiveness and side effects, but the treatment effects do not differ between compliers and never-takers.

Addressing vaccine hesitancy using local ambassadors: A randomized controlled trial in Indonesia

In settings where resistance and rampant misinformation against vaccines exist, the prospect of containing infectious diseases remains a challenge. Can delivery of information regarding the benefits of vaccination through personal home visits by local ambassadors increase vaccine uptake? We conduct a door-to-door randomized information campaign targeted towards COVID-19 unvaccinated individuals in rural Indonesia. We recruited ambassadors from local villages tasked to deliver information about COVID-19 vaccines and promote vaccination through one-on-one meetings, using an interpersonal behavioral change communication approach. To investigate which type of ambassador – health cadres, influential individuals, and laypersons – is the most effective, we randomly vary the type of ambassador that delivers the information at the village level. We find that the overall vaccination take-up is quite moderate and that there are no differences in vaccination outcomes across the treatment groups. These results highlight the challenge of boosting vaccine uptake in late stages of a pandemic.

A histopathological review of gynaecological malignancies in Katsina state North-Western Nigeria.

Gynaecological cancers, which affect the female genital tract, constitute a significant public health problem, especially in developing countries. Some of these malignancies have known aetiology and premalignant stages making them preventable. Understanding the burden of gynaecological malignancies in our environment will provide baseline information and help form strategies for their control. To describe the histological subtypes of gynaecological cancers, their frequency and age distribution trends in Katsina State over the 10-year study period. This was a 10-year retrospective cross-sectional multicenter study of all histologically diagnosed gynaecological cancer cases seen from 1st January 2012 to 31st December 2021 at Federal Teaching Hospital Katsina, General Hospital Katsina and General Amadi Rimi Specialist Hospital Katsina. Data for this study were extracted from departmental record registers of the pathology laboratories of the corresponding hospitals whose laboratories provide pathology services to the State. Cancer distribution over the years was sorted based on the primary site of diagnosis, histological diagnosis and age. Data were analysed using Statistical Package for Social Science version 28 and results were presented in tables and charts. Two thousand three hundred and fifty-nine cancers were seen over the 10-year study period. Of these cases, 58.4% (n = 1,378) were females. Gynaecological malignancies accounted for 18.7% (441/2,359) of all cancers and 32.0% (441/1,378) of all female cancers. The highest frequency of gynaecological cancers was seen in women who were within the age groups of 40-49 and 50-59, and the lowest was seen in women who were ≥90 years old. The mean age was 48.9 ± 14.9 years. The most common site of gynaecological malignancies was the cervix uteri (n = 262, 59.4%) followed by the ovary (n = 106, 24.0%). Other sites in descending order were corpus uteri (n = 29, 6.6%), vulva (n = 9, 2.0%) and vagina (n = 2, 0.5%). The most common histo-morphologic subtypes were large-cell keratinizing squamous cell carcinoma in the cervix, large-cell non-keratinizing squamous cell carcinoma in the cervix and cystadenocarcinoma in the ovary. Choriocarcinoma was found in 33 cases (7.5%). This study demonstrated the various histotypes of gynaecological malignancies and their trends in Katsina state. The leading cancer was found to be cervical cancer which is mainly preventable. It is hoped that data from this study will provide a basis for making and implementing policies and strategies to lessen the problems of gynaecological malignancies through regular screening programs, especially for cervical cancer and accepting human papilloma virus (HPV) vaccination take-up.

Sibling spillovers and the choice to get vaccinated: Evidence from a regression discontinuity design

We investigate the effects of introducing population-wide free-of-charge Human Papillomavirus (HPV) vaccination programs on the targeted adolescent cohorts and their siblings. For identification, we rely on regression discontinuity designs and high-quality Danish administrative data to exploit that date of birth determines program eligibility. We find that the programs increased the HPV vaccine take-up of both the targeted children (53.2 percentage points for girls and 36.0 percentage points for boys) and their older same-sex siblings (4.5 percentage points for sisters and 3.5 percentage points for brothers). We show that while the direct effects of the programs reduced HPV vaccine take-up inequality, the spillover effects, in contrast, contributed to an increase in vaccine take-up inequality highlighting the potential importance of spillover effects in the determination of distributional consequences of public health programs. Finally, we find some evidence of cross-vaccine spillovers.

Assessing COVID-19 vaccine hesitancy and barriers to uptake in Sub-Saharan Africa

BackgroundDespite improved availability of COVID-19 vaccines in Sub-Saharan Africa, vaccination campaigns in the region have struggled to pick up pace and trail the rest of the world. Yet, a successful vaccination campaign in Sub-Saharan Africa will be critical to containing COVID-19 globally.MethodsHere, we present new descriptive evidence on vaccine hesitancy, uptake, last-mile delivery barriers, and potential strategies to reach those who remain unvaccinated. Our data comes from national high frequency phone surveys in six countries in East and West Africa with a total population of 415 million people. Samples were drawn from nationally representative samples of households interviewed in recent in-person surveys. Our estimates are based on a survey module harmonized across countries and are re-weighted to mitigate potential sample selection biases.ResultsWe show that vaccine acceptance remains generally high among respondents in Sub-Saharan Africa (between 95.1% and 63.3%) even though hesitancy is non-negligible among those pending vaccination. Many who are willing to get vaccinated are deterred by a lack of easy access to vaccines at the local level. Furthermore, social ties and perceptions as well as intra-household power relations matter for vaccine take-up. Among the unvaccinated population, radio broadcasts have widespread reach and medical professionals are highly trusted.ConclusionsOur findings highlight that creating a positive social norm around COVID-19 vaccination, messaging that leverages trusted and accessible information sources and channels, and more easily accessible vaccination sites at the community level are promising policy options to boost vaccination campaigns in the region and end the pandemic everywhere.

Covid-19 Vaccines As a Condition of Employment: Impact on Uptake, Staffing, and Mortality in Elderly Care Homes

Laws mandating vaccination against Covid-19 as a condition of employment in health and care sectors were commonplace during the pandemic. Using weekly data at the local authority level, we examine the impact of the vaccine mandate for elderly care homes in England on vaccine take-up, staffing levels, and mortality. Our identification strategy involves (1) comparing take-up and staffing in English elderly care homes relative to other social care settings unaffected by the mandate; (2) comparing take-up and staffing in English elderly care homes relative to those in Wales where the mandate also did not apply; and (3) comparing Covid-19 mortality among English elderly care home residents relative to mortality in domestic homes in England and to care homes in Wales. Our results suggest that the mandate substantially decreased the proportion of care home workers who remained unvaccinated (equivalent to between 28,000 and 41,000 fewer unvaccinated staff), but this came at the cost of a reduction in staffing levels of between 3% and 4% (equivalent to 14,000 to 18,000 staff). We observe this effect most strongly in areas of low unemployment. Our results do not provide evidence that the vaccine mandate was successful in its primary aim of reducing care home deaths. Relatively wide confidence intervals mean inferences regarding mortality are more uncertain than for vaccination uptake and staffing. This paper was accepted by Carri W. Chan, healthcare management. Supplemental Material: The data and e-companion are available at https://doi.org/10.1287/mnsc.2023.4832 .

VaxxHesitancy: A Dataset for Studying Hesitancy towards COVID-19 Vaccination on Twitter

Vaccine hesitancy has been a common concern, probably since vaccines were created and, with the popularisation of social media, people started to express their concerns about vaccines online alongside those posting pro- and anti-vaccine content. Predictably, since the first mentions of a COVID-19 vaccine, social media users posted about their fears and concerns or about their support and belief into the effectiveness of these rapidly developing vaccines. Identifying and understanding the reasons behind public hesitancy towards COVID-19 vaccines is important for policy markers that need to develop actions to better inform the population with the aim of increasing vaccine take-up. In the case of COVID-19, where the fast development of the vaccines was mirrored closely by growth in anti-vaxx disinformation, automatic means of detecting citizen attitudes towards vaccination became necessary. This is an important computational social sciences task that requires data analysis in order to gain in-depth understanding of the phenomena at hand. Annotated data is also necessary for training data-driven models for more nuanced analysis of attitudes towards vaccination. To this end, we created a new collection of over 3,101 tweets annotated with users' attitudes towards COVID-19 vaccination (stance). Besides, we also develop a domain-specific language model (VaxxBERT) that achieves the best predictive performance (73.0 accuracy and 69.3 F1-score) as compared to a robust set of baselines. To the best of our knowledge, these are the first dataset and model that model vaccine hesitancy as a category distinct from pro- and anti-vaccine stance.

When reality bites: Local deaths and vaccine take-up

In this study, we investigate whether COVID-19 deaths that occurred before vaccination rollouts impact subsequent vaccination take-up. We use data on local vaccination rates and COVID-19-related deaths from England measured at high geographic granularity. We find that vaccination take-up as of November 2021 is positively associated with pre-vaccine COVID-19-related deaths, controlling for demographic, economic, and health-related characteristics of the localities, while including geographic fixed effects. In addition, the share of ethnic minorities in a locality is negatively associated with vaccination rates, and localities with a larger share of ethnic minorities increase their vaccination rates if they are exposed to more COVID-related-deaths. Further evidence on vaccination intention at the individual level from a representative sample corroborates these patterns. Overall, our evidence suggests that social proximity to victims of the disease triggers a desire to take protective measures against it.

Government Trust and COVID-19 Vaccination: The Role of Supply Disruptions and Political Allegiances in Sierra Leone

We use data on the universe of COVID-19 vaccines in Sierra Leone to examine the relationship between COVID-19 vaccination take-up and support for the party in power and whether interruptions to vaccine supply reduced take-up of second doses. We find that COVID-19 vaccine take-up is higher in areas that support the ruling party, but this mirrors long-term vaccination patterns and not the politicization of COVID-19 vaccines. People whose second dose was due just before and after a vaccine stockout had similar second take-up rates (around 50 percent)–that is, delayed access to second doses did not deter eventual take-up.

Desafios da imunização contra COVID-19 na saúde pública: das fake news à hesitação vacinal

Abstract This article aims to synthesize articles addressing fake news and COVID-19 vaccine hesitancy in the context of public health. We conducted an integrative review of articles published in any language between 2019 and 2022 in journals indexed in the following databases: Latin American and the Caribbean Literature on Health Sciences, Medical Literature Analysis and Retrieval System Online, Scopus, Web of Science, and Embase. A critical analysis was performed, guided by the research question and objective of the review. Eleven articles were selected, the overwhelming majority of which were cross-sectional studies. The main factors related to vaccine take-up highlighted by the studies were gender, age, education level, political leanings, religion, trust in health authorities, and perceptions of side-effects and vaccine efficacy. The main obstacles to attaining optimal vaccination coverage were vaccine hesitancy and disinformation. All studies addressed the relationship between low vaccination intention and the use of social media as a source of information about SARS-CoV-2. It is necessary to build public trust in vaccine safety and efficacy. Promoting a better understanding of the benefits of COVID-19 vaccination is essential to combat vaccine hesitancy and improve vaccine take-up.

COVID-19 vaccination intentions and subsequent uptake: An analysis of the role of marginalisation in society using British longitudinal data

COVID-19 vaccine hesitancy has previously been modelled using data on intentions – expressed prior to vaccine availability. Once vaccines became widely available, it became possible to model hesitancy using actual vaccination uptake data. This paper estimates the determinants of the joint distribution of COVID-19 vaccination intentions (declared before the release of any vaccine) and actual vaccination take-up (when it was widely available across the age distribution). We use high quality longitudinal data (UK Household Longitudinal Study) collected during the pandemic in the UK, merged to a wide variety of individual characteristics collected prior to the COVID-19 pandemic. Our estimation draws on pre-Covid values of variables for a sample that includes 10,073 observations from the September 2021 wave.The contribution of this paper is to model hesitancy and uptake jointly. The work shows that people who might be regarded as marginalised in society (measured, before the pandemic began) are less likely to say that they intend to be vaccinated and they go on to also be more likely to actually remain unvaccinated. It also shows that there is a large positive correlation between the unobservable determinants of intention and of uptake. This high positive correlation has an important implication - that information campaigns can be reasonably well profiled to target specific groups on the basis of intention data alone. We also show that changing one's mind is not correlated with observable data. This is consistent with two explanations. Firstly, the new information available on the arrival of vaccines, that they are safe and effective, may be more optimistic than was originally assumed. Secondly, individuals may have been more pessimistic about the effects associated with infection before vaccines became available.

The COVID-19 curtain: Can past communist regimes explain the vaccination divide in Europe?

As of December 2021, all former Communist countries from Central and Eastern Europe were still lagging behind in terms of COVID-19 vaccination rates in Europe. Can institutional legacy explain, at least in part, this heterogeneity in vaccination decisions across Europe? To study this question we exploit novel data from the second wave of the SHARE (Survey of Health, Ageing and Retirement in Europe) COVID-19 Survey fielded in Summer (2021) that covers older individuals in 27 European countries. First, we document lower COVID-19 vaccine take-up amongst those who were born under Communism in Europe. Next, we turn to reunified Germany to get closer to a causal effect of having lived behind the Iron Curtain. We find that exposure to the Communist regime in East Germany decreased one's probability to get vaccinated against COVID-19 by 8 percentage points and increased that of refusing the vaccine by 4 percentage points. Both effects are large and statistically significant, and they hold when controlling for individual socio-economic and demographic characteristics. We explore several possible mechanisms. The East-West Germany gap does not seem to be explained by differences in the impact of the first wave of the pandemic or in general exposure to vaccines. We find that East Germans have lower social capital than West Germans and that social capital correlates negatively with Covid-10 vaccine uptake, but only a small fraction of the East-West Germany Covid-19 vaccination gap can be explained by our measures of social capital.

The links between COVID-19 vaccine acceptance and non-pharmaceutical interventions

The information set from which individuals make their decision on vaccination includes signals from trusted agents, such as governments, community leaders and the media. By implementing restrictions, or by relaxing them, governments can provide a signal about the underlying risk of the pandemic and indirectly affect vaccination take-up. Rather than focusing on measures specifically designed to increase vaccine acceptance, this paper studies how governments' non-pharmaceutical policy responses to the pandemic can modify the degree of preventive health behavior, including vaccination. To do so, we use repeated waves of a global survey on COVID-19 Beliefs, Behaviors and Norms covering 18 countries from October 2020 to March 2021. Controlling for the usual determinants, we explore how individuals’ willingness to get vaccinated is affected by changes in government restriction measures (as measured by the Oxford Stringency Index). This relationship is mediated by individual characteristics, social norms (social pressure to conform with what most people do), and trust in government institutions. Our results point to a complex picture as the implementation of restrictions is associated with increased acceptance in some contexts and decreased acceptance in others. The stringency of government restrictions has significant positive correlations with vaccine acceptance in contexts of weak social norms of vaccine acceptance and lower trust in government. In countries or communities with tighter social norms and high trust in health authorities, vaccine acceptance is high but less sensitive to changes in policies. These results suggest that the effect of government policy stringency is stronger among individuals who report lower trust and weaker social norms of vaccine acceptance.

Assessment of COVID-19 vaccine take-up and its predictors among healthcare professionals in public hospitals, Addis Ababa, Ethiopia: Facility-based cross-sectional study

ABSTRACT Healthcare professionals (HCPs) are among the highly exposed groups for the COVID-19 pandemic and have been identified as the target population to get vaccination against the spread of the infection. Aimed to assess COVID-19 vaccine take-up and its predictors among HCPs in public hospitals in Addis Ababa, Ethiopia, 2021. A facility-based cross-sectional study was conducted among 403 randomly selected participants from October 1st to November 30, 2021. Data was entered into Epi-info version 7 and analyzed using SPSS version 25. An AOR along with a 95% confidence level was estimated, and a P value <.05 was considered to declare the statistical significance. About 71% of the participants had taken any of the COVID-19 vaccines at least once. Being married (AOR: 10.79; 95% CI: 1.32–18.05); educational status of MSc degree (AOR = 7.7; CI: 2.08–15.1.6), medical doctors/GP (AOR = 5.88; CI: 1.60–15.54), MD with MSc (AOR = 9.63; CI: 2.17–17.76), PHD (AOR = 13.33; CI: 1.23–24.21) and specialist and above 3 (AOR = 3.45; CI: 2.34–42.8) holder HCPs; perceived severity of COVID-19 infection as moderate (AOR = 0.23; CI: 0.08–0.65) and mild (AOR = 0.28; CI: 0.11–0.74) and poor knowledge toward COVID-19 vaccination (AOR = 0.03; CI: 0.01–0.12) were statistically associated. This study showed that COVID-19 vaccine take-up among HCPs was relatively low to achieve herd immunity. Participants’ marital status, educational status, perception of the severity of COVID-19 infection, and level of knowledge toward COVID-19 vaccines were the predictors of the COVID-19 vaccine take-up.

The Roles of Cost and Recommendations in Driving Vaccine Take-Up

The Roles of Cost and Recommendations in Driving Vaccine Take-Up

Motivations behind Vaccine Hesitancy: Examining Altruism and Government Distrust across Job Sectors during COVID-19

This article examines vaccination and vaccine hesitancy during the COVID-19 pandemic by focusing on the role of altruism and distrust in government across different job sectors. Using the Household Pulse Survey, a nationally representative and near real-time dataset administered by the United States Census Bureau, our findings suggest that there is a clear difference in vaccine take-up and vaccine hesitancy across job sectors. We find that government and nonprofit employees are more likely to receive vaccines and, if not vaccinated yet, are less vaccine-hesitant than private-sector employees. Additionally, motivations behind vaccine hesitancy, particularly altruism and distrust in government, varied according to one’s sector affiliation. Government and nonprofit employees, compared to private employees, were more likely to be vaccine hesitant for altruistic motivations. Differences in government distrust across sectors bore unexpected results, as we found no difference between government and private employees, while nonprofit employees were less likely to be vaccine hesitant due to government distrust. We discuss the implications and contributions of this article and suggest future agenda for COVID-19 research and sector comparison literature.

Establishing Covid-19 Research in UK Care Homes – Infrastructure Challenges for Trial Design

Abstract Background The Covid-19 pandemic brought into sharp relief the role that long-term care facilities play in health and social care of an aging population. It also cast a spotlight upon the need for high-quality research to assess the effectiveness of any care home interventions. The Prophylactic Therapies in Care Homes (PROTECT-CH) trial was one such study (funded by the UK National Institute for Health and Care Research). PROTECT-CH was designed to collect data in 200 care homes (approximately 6,400 residents), and whilst the changing epidemiology of Covid-19 in the UK (due to vaccination take-up) made this unfeasible other insights were gained about establishing large-scale research in care homes. Methods An iterative process evaluation of the set-up phase of a large, platform trial testing prophylactic measures in long-term care facilities. Including a documentary review of the PROTECT-CH working groups and an online survey of working group members. Results Documents were reviewed from 24 working groups, which in a hub and spoke model represented the PROTECT-CH trial infrastructure; representative of 20 of these groups completed an online survey about their organisation and working. Data demonstrated the number and organisation of individuals required to set up a large-scale care-home trial - 91 individuals representing a mix of academic, clinical, and methodological contributions from 25 organisations. Data demonstrated working groups specific to care home research, and activities designed to address the specific challenges of researching in care homes. PROTECT-CH produced dedicated training materials and reporting templates for care home research. PROTECT-CH established novel mechanisms for prescribing and clinical oversight in care home research. Conclusions PROTECT-CH has highlighted the complexity of establishing large, scale RCT research in long-term care facilities. It has produced resources which might be of use in subsequent care home research. Key messages • Infrastructure is required to support high quality research in long-term care facilities. • RCTs in long-term care facilities pose specific challenged to researchers.

Disruptions to healthcare quality and early child health outcomes: Evidence from health-worker strikes in Kenya

This paper measures the effects of disruptions to healthcare quality at birth on early child health outcomes in Kenya. To identify impacts, we exploit variation in the timing and location of health-worker strikes at individual hospitals across the country between 1999 and 2014. Using data from Demographic Health Surveys, we find that children born during strikes are more likely to suffer a neonatal death. We find similar results using separate data collected in two informal settlements in Nairobi located near hospitals with frequent strikes. These results show that interruptions to healthcare quality can have large immediate health impacts, and suggests that status quo hospital care provides positive benefits. We also find suggestive evidence of reductions in later health investments, measured by vaccine take-up, among those who survive. This study provides the first rigorous evidence on the consequences of health-worker strikes, a frequent but understudied phenomenon in Sub-Saharan Africa.