Factors associated with COVID-19 vaccination during June–October 2021: A multi-site prospective study

IntroductionVaccine hesitancy presents a challenge to COVID-19 control efforts. To identify beliefs associated with delayed vaccine uptake, we developed and implemented a vaccine hesitancy survey for the COVID-19 Community Research Partnership.MethodsIn June 2021, we assessed attitudes and beliefs associated with COVID-19 vaccination using an online survey. Self-reported vaccination data were requested daily through October 2021. We compared responses between vaccinated and unvaccinated respondents using absolute standardized mean differences (ASMD). We assessed validity and reliability using exploratory factor analysis and identified latent factors associated with a subset of survey items. Cox proportional hazards models and mediation analyses assessed predictors of subsequent vaccination among those initially unvaccinated.ResultsIn June 2021, 29,522 vaccinated and 1,272 unvaccinated participants completed surveys. Among those unvaccinated in June 2021, 559 (43.9 %) became vaccinated by October 31, 2021. In June, unvaccinated participants were less likely to feel “very concerned” about getting COVID-19 than vaccinated participants (10.6 % vs. 43.3 %, ASMD 0.792). Among those initially unvaccinated, greater intent to become vaccinated was associated with getting vaccinated and shorter time to vaccination. However, even among participants who reported no intention to become vaccinated, 28.5 % reported vaccination before study end. Two latent factors predicted subsequent vaccination—being ‘more receptive’ was derived from motivation to protect one’s own or others’ health and resume usual activities; being ‘less receptive’ was derived from concerns about COVID-19 vaccines. In a Cox model, both factors were partially mediated by vaccination intention.ConclusionThis study characterizes vaccine hesitant individuals and identifies predictors of eventual COVID-19 vaccination through October 31, 2021. Even individuals with no intention to be vaccinated can shift to vaccine uptake. Our data suggest factors of perceived severity of COVID-19 disease, vaccine safety, and trust in the vaccine development process are predictive of vaccination and may be important opportunities for ongoing interventions.     

Strategic silences,eroded trust: The impact of divergent COVID-19 vaccine sentiments on healthcare workers' relations with peers and patients

BackgroundPolarized debates about Covid-19 vaccination and vaccine mandates for healthcare workers (HCWs) challenge Belgian HCWs ability to discuss Covid-19 vaccine sentiments with peers and patients. Although studies have identified drivers of HCWs vaccine hesitancy, they do not include effects of workplace interactions and have not addressed consequences beyond vaccine coverage.MethodsInterviews and focus group discussions with 74 HCWs practicing in Belgium addressed Covid-19 vaccine sentiments and experiences of discussing vaccination with peers and patients.ResultsMost participating HCWs reported difficulties discussing Covid-19 vaccination with peers and patients. Unvaccinated HCWs often feared that expressing their vaccine sentiments might upset patients or peers and that they would be suspended. Consequently, they used social cues to evaluate others’ openness to vaccine-skeptical discourses and avoided discussing vaccines. Surprisingly, some vaccine-confident HCWs hid their vaccine sentiments to avoid peer and patient conflicts. Both vaccinated and unvaccinated HCWs observed that unvaccinated patients occasionally received suboptimal care. Suboptimal care was central in unvaccinated HCW unwillingness to express their vaccine sentiments to peers. Both vaccinated and unvaccinated HCWs described loss of trust and ruptured social relations with peers and patients holding divergent vaccine sentiments.DiscussionBelgian HCW perceived Covid-19 vaccines as a risky discussion topic and engaged in “strategic silences” around vaccination to maintain functional work relationships and employment in health institutions. Loss of trust between HCW and peers or patients, along with suboptimal patient care based on vaccination status, threaten to weaken Belgium’s, and by implication, other health systems, and to catalyze preventable disease outbreaks.     

Persistence of Vaccine Hesitancy and Acceptance of the EU Covid Certificate Among French Students

Covid-19 vaccine hesitancy among young adults is a current public health issue that needs to be addressed considering the seasonally driven waves of disease and the administration of vaccine boosters. As a prevention measure, the EU Covid certificate had been implemented to increase vaccine uptake, but its application was controversial. Our study investigated students’ opinions and attitudes towards Covid-19 vaccination and the EU Covid certificate through a mixed-methods design. An 18-item questionnaire was administered to 200 students during a vaccination campaign in September 2021 at the University of Bordeaux, France. Simultaneously, 30 students attended a semi-structured interview. Collected data were analyzed separately then discussed together through a parallel and convergent approach. Results showed that vaccine hesitancy was high among students, mostly from fear of short-term side effects. However, respondents decided to get vaccinated to obtain the EU Covid certificate, even if they considered it as a violation of their freedom. Straightforward communication about Covid-19 vaccination did not reach students, although this was a strong expectation from governmental and health institutions. Findings suggest that key health personnel should provide evidence-based information about vaccines in efforts of building trust with young people.

     

“They're trying to bribe you and taking away your freedoms”: COVID-19 vaccine hesitancy in communities with traditionally low vaccination rates

Vaccination is an essential public health intervention to control the COVID-19 pandemic. A minority of Canadians, however, remain hesitant about COVID-19 vaccines, while others outright refuse them. We conducted focus groups to gauge perceptions and attitudes towards COVID-19 vaccines in people who live in a region with historically low rates of childhood vaccination. Participants discussed their perception of COVID-19 vaccines and their intention to get vaccinated, and the low rate of COVID-19 vaccine uptake in Manitoba’s Southern Health Region compared to other regions in Canada. We identified three drivers of vaccine hesitancy: (1) risk perceptions about COVID-19 and the vaccines developed to protect against it, (2) religious and conservative views; and (3) distrust in government and science. Participant proposed recommendations for improving communication and uptake of the COVID-19 vaccines included: public health messages emphasising the benefits of vaccination; addressing the community’s specific concerns and dispelling misinformation; highlighting vaccine safety; and emphasising vaccination as a desirable behaviour from a religious perspective. Understanding the specific anxieties elicited by COVID-19 vaccines in areas with low childhood immunization rates can inform risk communication strategies tailored to increase vaccination in these specific regions. This study adds important information on potential reasons for vaccine hesitancy in areas with historically low rates of childhood vaccination, and provides important lessons learned for future emergencies in terms of vaccine hesitancy drivers and effective risk communication to increase vaccine uptake.     

Willingness of Brazilian caregivers in having their children and adolescents vaccinated against Covid-19

BackgroundThe vaccination of children and adolescents for the prevention of Covid-19 is important to:decrease in deaths and hospitalizations, prevent multisystem inflammatory syndrome, avoid long-term complications and decrease the suspension of on-site classes. Despite of these benefits, some studies have shown that some caregivers are still hesitancy.MethodsThis is a voluntary and anonymous online survey conducted from November 17 to December 14, 2021, in Brazil, through a free-of-charge platform with a link provided on social networks. A bivariate analysis was conducted with the independent variables, with vaccine hesitancy as the outcome variable, and a multivariate logistic model was used to calculated adjusted odds ratios.ResultsThe sample included 15,297 respondents. Approximately 13.3 % (2,028) of the caregivers were hesitant to vaccinate their children and adolescents against Covid-19 in at least one age group. The vaccination hesitanty rate of caregivers of children aged 0–4 years, 5–11 years and adolescents were 16 %, 13 %, 15 %, respectively. The principal factors associated with vaccine hesitancy were the following: belief that they need to wait longer, belief that children that had natural infection doesn’t need to vaccinate and belief that vaccine has long term adverse effects.Interpretation.The present study showed that the willingness of caregivers to have their children and adolescents vaccinated in Brazil is high compared to data from adult and pediatric international studies. This study provides a profile of the hesitant caregivers considering their perspectives and beliefs regarding vaccines that can help the elaboration of strategies to increase vaccine adherence.     

Patterns and influencing factors of COVID-19 vaccination willingness among college students in China

BackgroundVaccination is an important preventive measure against the coronavirus disease 19 (COVID-19) pandemic. We aimed to examine the willingness to vaccination and influencing factors among college students in China.MethodsFrom March 18 to April 26, 2021, we conducted a cross-sectional online survey among college students from 30 universities in Wuhan, Hubei Province, China. The survey was composed of the sociodemographic information, psychological status, experience during pandemic, the willingness of vaccination and related information. Students’ attitudes towards vaccination were classified as ‘vaccine acceptance’, ‘vaccine hesitancy’, and ‘vaccine resistance’. Multinomial logistic regression analyses were performed to identify the influencing factors associated with vaccine hesitancy and resistance.ResultsAmong 23,143 students who completed the survey, a total of 22,660 participants were included in the final analysis with an effective rate of 97.9% after excluding invalid questionnaires. A total of 60.6% of participants would be willing to receive COVID-19 vaccine, 33.4% were hesitant to vaccination, and 6.0% were resistant to vaccination. Social media platforms and government agencies were the main sources of information vaccination. Worry about the efficacy and adverse effects of vaccine were the top two common reason of vaccine hesitancy and resistance. Multiple multinomial logistic regression analysis identified that participants who worried about the adverse effects of vaccination were more likely to be vaccine hesitancy (aOR = 2.44, 95% CI = 2.30, 2.58) and resistance (aOR = 2.71, 95% CI = 2.40, 3.05).ConclusionMore than half of college students are willing to receive the COVID-19 vaccine, whereas nearly one-third college students are still hesitant or resistant. It is crucial to provide sufficient and scientific information on the efficacy and safety of vaccine through social media and government agencies platforms to promote vaccine progress against COVID-19 and control the pandemic in China.     

Factors influencing Covid-19 vaccine acceptance across subgroups in the United States: Evidence from a conjoint experiment

Public health officials warn that the greatest barrier to widespread vaccination against Covid-19 will not be scientific or technical, but the considerable public hesitancy to take a novel vaccine. Understanding the factors that influence vaccine acceptance is critical to informing public health campaigns aiming to combat public fears and ensure broad uptake. Employing a conjoint experiment embedded on an online survey of almost 2,000 adult Americans, we show that the effects of seven vaccine attributes on subjects’ willingness to vaccinate vary significantly across subgroups. Vaccine efficacy was significantly more influential on vaccine acceptance among whites than among Blacks, while bringing a vaccine to market under a Food and Drug Administration Emergency Use Authorization had a stronger adverse effect on willingness to vaccinate among older Americans and women. Democrats were more sensitive to vaccine efficacy than Republicans, and both groups responded differently to various endorsements of the vaccine. We also explored whether past flu vaccination history, attitudes toward general vaccine safety, and personal contact with severe cases of Covid-19 can explain variation in group vaccination hesitancy. Many subgroups that exhibit the greatest Covid-19 vaccine hesitancy did not report significantly lower frequencies of flu vaccination. Several groups that exhibited greater Covid-19 vaccine hesitancy also reported greater concerns about vaccine safety generally, but others did not. Finally, subgroup variation in reported personal contact with severe cases of Covid-19 did not strongly match subgroup variation in vaccine acceptance.     

Vaccination willingness,vaccine hesitancy,and estimated coverage at the first round of COVID-19 vaccination in China: A national cross-sectional study

BackgroundVaccination against coronavirus disease 2019 (COVID-19) has become an important public health solution. To date, there has been a lack of data on COVID-19 vaccination willingness, vaccine hesitancy, and vaccination coverage in China since the vaccine has become available.MethodsWe designed and implemented a cross-sectional, population-based online survey to evaluate the willingness, hesitancy, and coverage of the COVID-19 vaccine among the Chinese population. 8742 valid samples were recruited and classified as the vaccine-priority group (n = 3902; 44.6%) and the non-priority group (n = 4840; 55.4%).ResultsThe proportion of people’s trust in the vaccine, delivery system, and government were 69.0%, 78.0% and 81.3%, respectively. 67.1% of the participants were reportedly willing to accept the COVID-19 vaccination, while 9.0% refused it. 834 (35.5%) reported vaccine hesitancy, including acceptors with doubts (48.8%), refusers (39.4%), and delayers (11.8%). The current coverage was 34.4%, far from reaching the requirements of herd immunity. The predicted rate of COVID-19 vaccination was 64.9%, 68.9% and 81.1% based on the rates of vaccine hesitancy, willingness, and refusal, respectively.ConclusionsThe COVID-19 vaccine rate is far from reaching the requirements of herd immunity, which will require more flexible and comprehensive efforts to improve the population’s confidence and willingness to vaccinate. It should be highlighted that vaccination alone is insufficient to stop the pandemic; further efforts are needed not only to increase vaccination coverage but also to maintain non-specific prevention strategies.     

COVID-19 Vaccination Intent and Belief that Vaccination Will End the Pandemic

High vaccination coverage is considered to be key in dealing with the coronavirus disease (COVID-19) pandemic. However, vaccine hesitancy can limit uptake. We examined the specific coronavirus beliefs that persons have regarding COVID-19 and COVID-19 vaccines and to what extent these beliefs explain COVID-19 vaccination intentions. We conducted a survey among 4,033 residents of the Netherlands that examined COVID-19 vaccination intentions and various beliefs. Random forest regression analysis explained 76% of the variance in vaccination intentions. The strongest determinant in the model was the belief the COVID-19 crisis will only end if many persons get vaccinated. Other strong determinants were beliefs about safety of vaccines, specifically in relation to vaccine development and approval process; (social) benefits of vaccination; social norms regarding vaccination behavior; and effectiveness of vaccines. We propose to address these specific beliefs in communications about COVID-19 vaccinations to stimulate vaccine uptake.     

International estimates of intended uptake and refusal of COVID-19 vaccines: A rapid systematic review and meta-analysis of large nationally representative samples

BackgroundWidespread uptake of COVID-19 vaccines will be essential to controlling the COVID-19 pandemic. Vaccines have been developed in unprecedented time and quantifying levels of hesitancy towards vaccination among the general population is of importance.MethodsSystematic review and meta-analysis of studies using large nationally representative samples (n ≥ 1000) to examine the percentage of the population intending to vaccinate, unsure, or intending to refuse a COVID-19 vaccine when available. Generic inverse meta-analysis and meta-regression were used to pool estimates and examine time trends. PubMed, Scopus and pre-printer servers were searched from January-November 2020. Registered on PROSPERO (CRD42020223132).FindingsTwenty-eight nationally representative samples (n = 58,656) from 13 countries indicate that as the pandemic has progressed, the percentage of people intending to vaccinate decreased and the percentage of people intending to refuse vaccination increased. Pooled data from surveys conducted during June-October suggest that 60% (95% CI: 49% to 69%) intend to vaccinate and 20% (95% CI: 13% to 29%) intend to refuse vaccination, although intentions vary substantially between samples and countries (I² > 90%). Being female, younger, of lower income or education level and belonging to an ethnic minority group were consistently associated with being less likely to intend to vaccinate. Findings were consistent across higher vs. lower quality studies.InterpretationIntentions to be vaccinated when a COVID-19 vaccine becomes available have been declining across countries and there is an urgent need to address social inequalities in vaccine hesitancy and promote widespread uptake of vaccines as they become available.FundingN/A.     

Parental Perspectives on Immunizations: Impact of the COVID-19 Pandemic on Childhood Vaccine Hesitancy

Childhood vaccine hesitancy has been studied extensively before the COVID-19 pandemic. The pandemic presented new barriers to pediatric vaccinations. Furthermore, the development of COVID-19 vaccines has complicated factors underlying vaccine hesitancy. We performed a cross-sectional mobile phone-based survey at Children’s Hospital Los Angeles querying parents regarding perspectives on vaccines before and during the pandemic. Our primary aim was to understand the impact of the pandemic on routine childhood vaccine hesitancy. Secondarily, we examined intent to vaccinate, COVID-19 vaccine hesitancy, and key contributing demographic factors. Among 252 participants, we found overall increased childhood vaccine hesitancy (p?=?0.006), increased risk perception (p?=?0.006), and unchanged vaccine confidence during the COVID-19 pandemic. Increased hesitancy did not translate into decreased intent to vaccinate with routine childhood vaccines or influenza vaccines. During the pandemic, households with higher income (50–99 K, >?100 K) correlated with decreased routine childhood vaccine hesitancy, while Hispanic ethnicity and African American race had increased risk perception. For COVID-19 vaccine hesitancy, households with higher income (>?100 K) correlated with decreased hesitancy, while non-White ethnicity and race had increased risk perception. We found that routine childhood vaccine hesitancy increased during the COVID-19 pandemic, mainly due to increased risk perception. Key contributing demographic factors behind both childhood vaccine hesitancy and COVID-19 vaccine hesitancy included household income and race. Understanding factors behind routine childhood vaccine hesitancy is crucial to maintaining pediatric vaccination rates and promoting vaccine confidence during and after the COVID-19 pandemic.

     

The continuum of influenza vaccine hesitancy among nursing professionals in Hong Kong

IntroductionInfluenza vaccine hesitancy among healthcare workers poses challenges to the achievement of herd immunity and causes infection risks to vulnerable patients. This study aimed to quantify the extent of influenza vaccine hesitancy among nurses in Hong Kong, to delineate its pattern, and to explore its socio-demographic, professional and personal correlates.MethodNurses in Hong Kong were recruited in a cross-sectional study involving the administration of an online questionnaire survey after the 2017/18 winter influenza season. Respondents’ influenza vaccination behaviours, attitudes and psychological antecedents were assessed, followed by their delineation into subgroups along the hesitancy continuum through a combination of multiple correspondence analysis and K-means cluster analysis. Socio-demographic, professional and personal correlations of subgrouping were investigated using generalised ordered logistic regression.ResultsThe overall vaccination coverage of nurses for the 2017/18 influenza season was 44%. Five clusters were differentiated by the level of influenza vaccine hesitancy: “Very high hesitancy-to-complete refusal” (n = 56; 7%) characterised by outright refusal of vaccination; “High hesitancy” (n = 171; 23%) distinguished by tendency of skipping vaccination and scepticism about safety of vaccine; “Moderate hesitancy” (n = 273; 36%) with uncertainties towards vaccination, mistrust of the government’s vaccine recommendations and priority concern on affordability of vaccine; “Low hesitancy” (n = 95; 13%) with cautious acceptance towards vaccination and “No-to-minimal hesitancy” (n = 158; 21%) with strong vaccine confidence and compliance greatly linked to convenience of vaccine access. Nurses having completed at least 3 years’ pre-registration professional training, having most family members vaccinated against influenza, and with influenza vaccination history during studentship were less vaccine hesitant.ConclusionWith more than half of the nurses in Hong Kong having moderate or higher level of influenza vaccine hesitancy, interventions customised to the needs of nurses as reflected from the characteristics of clusters along the vaccine hesitancy continuum could form an important strategy for improving vaccination uptake.     

Social norms and vaccine uptake: College students’ COVID vaccination intentions,attitudes, and estimated peer norms and comparisons with influenza vaccine

BackgroundVaccination may be critical to curtailing the spread of the SARS-CoV-2 virus responsible for the COVID-19 pandemic, but herd immunity can only be realized with high vaccination coverage. There is a need to identify empirically supported strategies to increase uptake, especially among young adults as this subpopulation has shown relatively poor adherence to physical distancing guidelines. Social norms – estimates of peers’ behavior and attitudes – are robust predictors of health behaviors and norms-based intervention strategies may increase COVID vaccine uptake, once available. This study examined the extent that vaccination intentions and attitudes were associated with estimated social norms as an initial proof-of-concept test.MethodIn November of 2020, 647 undergraduate students (46.21% response rate) completed online surveys in which they reported intentions to get COVID and influenza vaccines, perceived importance of these vaccines for young adults, and estimated social norms regarding peers’ vaccination behaviors and attitudes.ResultsStudents reported significantly greater intentions to get a COVID vaccine (91.64%) than an influenza vaccine (76.04%), and perceived COVID vaccination as significantly more important than influenza vaccination. The sample generally held strong intentions to receive a COVID vaccine and thought that doing so was of high importance, but participants, on average, perceived that other young adults would be less likely to be vaccinated and would not think vaccination was as important. Multiple regression models indicated that estimated social norms were positively associated with participants’ own intentions and perceived importance of getting a COVID vaccine.ConclusionsThese significant associations highlight the potential value in developing and testing norms-based intervention strategies, such as personalized normative feedback, to improve uptake of forthcoming COVID vaccines among young adults.     

Increasing acceptance of a vaccination program for coronavirus disease 2019 in France: A challenge for one of the world’s most vaccine-hesitant countries

France is one of the most vaccine-hesitant countries in the world, including for coronavirus disease 2019 (COVID-19). After 10 months of restrictive measures and media coverage of the dangers of COVID-19, French attitudes towards a vaccine continue to deteriorate. The communication strategies of the government have not helped; in fact, they have made the situation worse.Empirical studies on the national strategy for management of the COVID-19 pandemic in France have shed light on the reasons for vaccine hesitancy. These studies have identified four pillars for the vaccination strategy: i) Communication regarding the importance of herd immunity, ii) making healthcare workers the focus of the vaccination campaign, iii) citizen mobilization and guaranteed consultations, and iv) access to free vaccines without delay. This paper discusses the evidence supporting this strategy.     

Uptake of COVID-19 vaccines among healthcare workers and the effect of nudging interventions: A mixed methods study

BackgroundDuring the coronavirus disease (COVID-19) pandemic, vaccination of healthcare workers (HCWs) has a critical role because of their high-risk exposure and being a role model. Therefore, we aimed to investigate vaccine hesitancy and the role of mandatory polymerase chain reaction (PCR) testing and education for vaccine uptake.MethodsWe conducted an explanatory sequential designed observational mixed-methods study, including quantitative and qualitative sections consecutively in two different pandemic hospitals between 15 September 2021 and 1 April 2022. The characteristics of vaccinated and unvaccinated HCWs were compared. The vaccine hesitancy scales were applied, and the effect of nudging, such as mandatory PCR and education, were evaluated. In-depth interviews were performed to investigate the COVID-19 vaccine hesitancy among HCWs according to Health Belief Model.ResultsIn total, 3940 HCWs were included. Vaccine hesitancy was more common among males than females, the ancillary workers than other health professions, and nonmedical departments than other departments. After the mandatory weekly PCR request nudge, 83.33 % (130/156) vaccine-hesitant HCWs were vaccinated, and 8.3 % (13/156) after the small group seminars and mandatory PCR every two days. The rate of COVID-19 vaccination was raised from 95.5 % to 99.67 % (3927/3940). At the end of in-depth interviews (n = 13), the vaccine hesitancy determinants were distrust, fear of uncertainty, immune confidence and spirituality, the media effect, social pressure, and obstinacy.ConclusionsThe nudging interventions such as mandatory PCR testing and small group seminars helped raise the rate of COVID-19 vaccination; the most effective one is mandatory PCR.     

COVID-19 vaccination hesitancy among Americans with disabilities aged 18-65: An exploratory analysis

BackgroundIt is important for people with disabilities to be vaccinated against COVID-19 because, as a group, they are at increased risk of severe outcomes. While there are multiple vaccines available to prevent COVID-19, a considerable proportion of Americans report some hesitancy to becoming vaccinated, including people with disabilities.ObjectiveWe conducted a study to explore what factors may contribute to COVID-19 vaccination hesitancy among Americans with disabilities.MethodsWe used Amazon's Mechanical Turk to survey 439 people with disabilities (ages 18+) about their concerns of the COVID-19 disease, vaccines, and hesitancy toward vaccination to learn more about factors that influence vaccination hesitancy. Concerns about vaccines were analyzed as a composite variable representing different dimensions such as: side effects, too new, developed too quickly, influenced by politics, and effectiveness.ResultsResults from a logistic regression indicate that concern about vaccines was the most significant predictor of hesitancy, even after considering demographic, economic, and geographic factors. Concerns about getting COVID-19, getting tested for COVID-19, trust in experts, education, and being a Democrat were negatively associated with hesitancy.ConclusionsThese findings indicate that some groups of individuals may be more vaccination hesitant because they are more concerned about vaccine safety than COVID-19 infection. Public health messaging that focuses on the risks of vaccines relative to the risks of COVID-19 might be one strategy to reduce hesitancy and increase vaccination uptake. Messaging should also be tailored to specific disabilities (i.e. physical, mental, sensory), written in plain language, and disseminated in accessible formats.     

Adolescents’ attitudes to the COVID-19 vaccination

Vaccines against COVID-19 are now available for adolescents in Hong Kong but vaccine hesitancy is a major barrier to herd immunity. This survey study explores Hong Kong adolescents’ attitudes towards the COVID-19 vaccination. 2609 adolescents from across Hong Kong completed an online survey focused on the intent to vaccinate and the reasons for their choice. 39% of adolescents intended to take the COVID-19 vaccination and significant factors for this decision include: having at least one parent vaccinated, knowing somebody diagnosed with COVID-19 and receiving the influenza vaccine. Adolescents’ major concerns were either the safety and efficacy of the vaccine or the risk of infection. This study has proved that even in adolescents the vaccine hesitancy model is prominent with adolescents’ intentions highly related to confidence in the vaccine and perception of disease risk. Future interventions should target these specific concerns to ensure adolescents are well educated to overcome vaccine hesitancy.     

Impact of national Covid-19 vaccination Campaign,South Korea

BackgroundWe evaluate the overall effectiveness of the nationwide vaccination campaign using ChAdOx1 nCoV-19, BNT162b2, mRNA-1273, and Ad26.COV2.S vaccines in preventing Covid-19 in South Korea.MethodsThe National Surveillance System with the National Immunization Registry were linked to form a large-linked database for assessment. Age-adjusted incidence of SARS-CoV-2 infection, severe disease, and death by vaccination status are calculated. Weekly vaccine effectiveness was calculated based on incidence rate ratio (IRR) between fully-vaccinated and unvaccinated persons, as: IRR = incidence rate of vaccinated / incidence rate of unvaccinated. We estimate the cumulative SARS-CoV-2 outcome overtime comparing the observed case with predicted cases without vaccination.ResultsAge-adjusted incidence in unvaccinated persons (5.69 per 100,000 person-day) was 2.7 times the rate in fully vaccinated (2.13 per 100,000 person-day) persons, resulting effectiveness against SARS-CoV-2 infection of 63%. Vaccine effectiveness against severe disease and death were 93% and 95%, respectively. Between March and October 2021, estimated Covid-19 related outcomes averted by vaccinations were: 46,508 infections, 3,424 severe diseases, and 718 deaths.ConclusionsWe found significant protection for national Covid-19 vaccination campaign against Covid-19 severe disease, and death in target populations, but there was an unexpected decreased protection against SARS-CoV-2 infection, highlighting the importance of continued surveillance and assessment.