Preparing for the Coronavirus Disease (COVID-19) Vaccination: Evidence, Plans, and Implications

Immediate adverse events following immunization (AEFI) in drive-through COVID-19 vaccination campaign in Yogyakarta, Indonesia: A cross-sectional study

Background & objectives The COVID-19 pandemic has led to unprecedented global immunization efforts, with drive-through vaccination campaigns established to expedite and ensure safe coverage. However, research on immediate adverse events following immunization (AEFI) in these settings is limited. This study aims to evaluate the frequency and characteristics of immediate AEFI during drive-through COVID-19 vaccination campaigns in Yogyakarta, Indonesia, using the Sinovac/CoronaVac vaccine Methods This cross-sectional study utilized secondary data from the local vaccine registry managed by the Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Indonesia, from July 27 to September 6, 2021. Participants included individuals aged over 11 yr without underlying medical conditions such as diabetes, hypertension, cancer, or asthma. Key characteristics recorded were age, gender, and AEFI. Results Out of 27,459 registrants, only 20,817 were eligible and received a dose. The median participant age was 20 yr (IQR 10); 47 per cent were male (9,712) and 53 per cent female (11,105). The highest vaccination day was September 6, 2021, with 3,883 doses (18%). Among the 79 participants who experienced AEFI [0.38%; 95% Confidence Interval (CI): 0.30-0.47], the median age was 19 yr (IQR 8); 41 per cent were male (34) and 59 per cent female (48). Systemic adverse events (92%) were more common than local events (6.3%), with dizziness (77.2%) being most prevalent. Interpretation & conclusions The findings of this study suggest that immediate AEFI occurred rarely in the drive-through vaccination setting, indicating that this method appears safe and efficient for COVID-19 vaccinations, particularly in the context of immediate AEFI. Most adverse events were mild, underscoring the importance of preparedness and close monitoring in drive-through vaccination campaign sites to ensure patient safety and enhance vaccine confidence.

The impact of COVID-19 status and vaccine type following the first dose on acute heart disease: A nationwide retrospective cohort study in South Korea

Recent studies have suggested an increased incidence of myocarditis and pericarditis following mRNA vaccination or COVID-19. However, the potential interaction effect between vaccine type and COVID-19 on heart disease risk remains uncertain. Our study aimed to examine the impact of COVID-19 status and vaccine type following the first dose on acute heart disease in the Korean population, using data from the National Health Insurance Service COVID-19 database (October 2018-March 2022). We sought to provide insights for public health policies and clinical decisions pertaining to COVID-19 vaccination strategies. We analysed heart disease risk, including acute cardiac injury, acute myocarditis, acute pericarditis, cardiac arrest, and cardiac arrhythmia, in relation to vaccine type and COVID-19 within 21 days after the first vaccination date, employing Cox proportional hazards models with time-varying covariates. This study included 3,350,855 participants. The results revealed higher heart disease risk in individuals receiving mRNA vaccines than other types (adjusted HR, 1.48; 95% CI, 1.35-1.62). Individuals infected by SARS-CoV-2 also exhibited significantly higher heart disease risk than those uninfected (adjusted HR, 3.56; 95% CI, 1.15-11.04). We found no significant interaction effect between vaccine type and COVID-19 status on the risk of acute heart disease. Notably, however, younger individuals who received mRNA vaccines had a higher heart disease risk compared to older individuals. These results may suggest the need to consider alternative vaccine options for the younger population. Further research is needed to understand underlying mechanisms and guide vaccination strategies effectively.

Effects of the COVID-19 Pandemic on the Medical Use of Elderly Patients with Hypertension: A Nationwide Cohort Study in Korea

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has disrupted healthcare services, including chronic disease management, for vulnerable groups, such as older individuals with hypertension. This study aimed to evaluate hypertension management in South Korea's elderly population during the pandemic using treatment consistency indices such as the continuity of care (COC), modified, modified continuity index (MMCI), and most frequent provider continuity (MFPC).

METHODS

This study used the Korea Disease Control and Prevention Agency-COVID-19-National Health Insurance Service cohort (K-COV-N cohort) from the National Health Insurance Service between 2017 and 2021. The research included a total of 4,097,299 hypertensive patients aged 65 years or older. We defined 2018 and 2019 as the baseline period before the COVID-19 pandemic and 2020 and 2021 as the COVID-19 period and calculated the indices of medical continuity (number of visits, COC, MMCI, and MFPC) on a yearly basis.

RESULTS

The number of visits decreased during the COVID-19 period compared to the baseline period (59.64±52.75 vs. 50.49±50.33, P<0.001). However, COC, MMCI, and MFPC were not decreased in the baseline period compared to the COVID-19 period (0.71±0.21 vs. 0.71±0.22, P<0.001; 0.97±0.05 vs. 0.96±0.05, P<0.001; 0.8±0.17 vs. 0.8±0.17, P<0.001, respectively).

CONCLUSION

COVID-19 had no significant impact on the continuity of care but affected the frequency of outpatient visits for older patients with hypertension. However, this study highlights the importance of addressing healthcare inequalities, especially in older patients with hypertension, during pandemics and advocates for policy changes to ensure continued care for vulnerable populations.

Evaluation of short-term adverse events of COVID-19 vaccines: An observational study

Coronavirus disease 2019 (COVID-19) vaccines are the most effective tools in managing the pandemic. However, the concern about these vaccines is the occurrence of unwanted adverse events (AEs). This study aimed to evaluate the short-term AEs of COVID-19 vaccines (Sputnik V, Astrazenka, and Sinopharm). A cross-sectional study using an online questionnaire was conducted among 321 vaccinated individuals. Demographic information, history of drug use, prior infection with COVID-19, the type of vaccine, vaccination stage, local injection site complication, systemic complication, and allergic reactions were collected and evaluated. Local complications, including pain and swelling at the injection site, and systemic complications, including fever, fatigue, lethargy, lymphadenopathy, and diarrhea, were reported after the injection of the AstraZeneca vaccine was more than the other 2 vaccines; The prevalence of fatigue and lethargy was higher than other systemic complications. The least reported complication was due to lymphadenopathy. The Sinopharm vaccine showed a lower prevalence of AEs than the other 2. The rare AEs, such as facial paralysis, nasal bleeding, and urticarial, were further reported after injection of the AstraZeneca vaccine. In general, the severity of systemic complications after the second dose of the vaccine was also higher than the first dose. All 3 vaccines were safe and tolerable. The most commonly reported AEs were injection site pain (local) and fatigue and lethargy (systemic). These expected AEs occurred shortly after vaccination and indicated an early immune response after vaccination.

Realistic Estimation of COVID-19 Infection by Seroprevalence Surveillance of SARS-CoV-2 Antibodies: An Experience From Korea Metropolitan Area From January to May 2022

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally, leading to the coronavirus disease 2019 (COVID-19) pandemic. Because a significant proportion of the COVID-19 confirmed cases were concentrated in the capital metropolitan area of South Korea, and a large proportion of the population in the area had been adequately vaccinated against COVID-19, we conducted a seroprevalence surveillance study focusing on the residents of the capital metropolitan area in South Korea.

METHODS

We used a quota-sampling method to obtain blood samples from 1,000 individuals per round, equally stratified across seven age categories and sexes and regions, from five medical institutions located within the capital metropolitan area of South Korea. During five consecutive months (rounds) between January 2022 and May 2022, a total of 5,000 samples were analyzed for anti-spike (S) and anti-nucleocapsid (N) antibodies.

RESULTS

High anti-S seropositivity was observed in all age groups, which corresponded to the vaccine coverage during the study period. Both the cumulative incidence based on polymerase chain reaction (PCR) and the estimated seroprevalence based on anti-N seropositivity increased in the fourth and fifth rounds, which corresponded to April 2022 and May 2022. Seroprevalence coincided with the cumulative incidence during the first three rounds, but exceeded from the fourth survey onwards when infection with omicron variants was increased rapidly in Korea.

CONCLUSION

Seroprevalence confirmed the number of infection cases outside of PCR testing-based surveillance. Seroepidemiological surveillance can help us understand vaccine responses and detect hidden infections, thereby providing appropriate public health guidance for achieving population-level immunity.

Expertise as a Response to Limited Multilateralism: The Case of South Korea's Vaccine Procurement Task Force for COVID-19 Vaccines amid Unequal Access via the COVAX Facility

This study investigates South Korea's trials and errors in procuring COVID-19 vaccines from abroad, amid the limitations of a multilateral scheme for global provision through the COVID-19 Vaccines Global Access (COVAX) program via the World Health Organization (WHO) and the discussions on COVID-19 vaccine patent waivers at the World Trade Organization. Using the framework of "self-help" in the international system and country categorization to explicate country behaviors by state-business relations and expertise to explain South Korea's COVID-19 vaccine procurement process, this study argues that in the absence of a global mechanism that guarantees adequate and timely vaccine provision, countries are left to the sole option of depending on their own capabilities: expertise, budget, and policy planning by consolidating public and private capacities to acquire vaccines for the public. To support the argument, an in-depth case investigation of South Korea's Vaccine Procurement Task Force is presented. The case study focuses on the policy assessment of critical elements in South Korea's vaccine procurement and rollout on facing obstacles to sufficient procurement through COVAX: decision-making impacting the timing and dosage of procurement, diplomatic and business channels to sign bilateral contracts, setup of a smart-factory vaccination hub, and indigenous vaccine development for WHO approval.

Vaccine effectiveness of COVID-19 and rebound in the real world

We intend to evaluate the relationship between the rates of global SARS-CoV-2 vaccination and the number of COVID-19 confirmed cases, as well as the mortality rate after the declaration of a pandemic. Of the data from 191 countries at the time of data retraction, we selected 111 countries that have SARS-CoV-2 vaccination reports. We stratified countries into high-income and non-high-income countries (HIC and non-HIC) based on World Bank income-group. We used a fixed-effects model (FEM) and performed a longitudinal analysis. The number of confirmed cases decreased as the vaccination rates increased in both non-HICs (B =  - 0.027, T =  - 2.0) and HICs (B =  - 0.207, T =  - 17.5). The number of deaths decreased as the vaccination rates increased in both non-HICs (B =  - 0.151, T =  - 2.3) and HICs (B =  - 0.230, T =  - 40.9). For full vaccination, this measure had a negative association with daily confirmed cases and daily deaths in both non-HICs and HICs. In non-HICs, daily cases and daily deaths decreased as the first vaccination and full vaccination coverages increased. However in HICs, daily cases and daily deaths decreased as the first vaccination and full vaccination coverages increased in the early phase, but after a certain period, they tended to increase again. We observed a significant association between the increase in vaccination coverage in the real world and reduced daily confirmed cases and deaths. However, as the confirmed cases and deaths have rebounded in HICs, our findings indicate that COVID-19 is not completely prevented through vaccine distribution.

Effective Vaccination and Education Strategies for Emerging Infectious Diseases Such as COVID-19

Social isolation and control owing to coronavirus disease 2019 (COVID-19) are easing; however, concerns regarding new infectious diseases have not disappeared. Given epidemic experiences such as severe acute respiratory syndrome (SARS), the influenza pandemic, Middle East respiratory syndrome (MERS), and COVID-19, it is necessary to prepare for the outbreak of new infectious diseases and situations in which large-scale vaccinations are required. Although the development of vaccines against COVID-19 has contributed greatly to overcoming the pandemic, concerning vaccine side effects from the general public, including medical personnel, and decreased confidence in vaccine efficacy and side effects, present many challenges in promoting and educating vaccinations for new infectious diseases in the future. In addition to plans to develop vaccines for the outbreak of new infectious diseases, education and promotion plans are necessary to administer the latest developments of vaccines to the general public. Moreover, efforts are needed to secure the necessity, legitimacy, and evidence for rapid vaccination on a large scale at the national level. It is also necessary to carefully prepare scientific bases and explanatory statements so that the general public can easily understand them. This study aimed to establish vaccine strategies and vaccination education plans for new infectious diseases that may occur in the future. Many ways to promote vaccination to the general public and healthcare workers should be prepared to ensure that the latest vaccines against new infectious diseases are administered safely. Thus, education and promotion of vaccine efficacy and safety based on specific data from clinical studies are necessary.

The Impact of Entry Restrictions on the Spread of Severe Acute Respiratory Syndrome Coronavirus Variants Between 2021 and 2022

To contain the surge of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the South Korean government has implemented non-pharmacological interventions as well as border restrictions. The efficacy of entry restrictions should be evaluated to facilitate their preparation for new variants of SARS-CoV-2. This study explored the impact of border policy changes on overseas entrants and local cases of SARS-CoV-2 variants. Data from the Korea Disease Control and Prevention Agency randomly collected between April 11, 2021 and August 20, 2022 were evaluated using the Granger causality model. The results showed that the outbreak gap of delta variants between international and domestic cases was 10 weeks, while that of omicron variants was approximately 2 weeks, meaning that the quarantine policy helped contain delta variants rather than more transmissible variants. It is recommended that countries implement quarantine policies based on particular purposes accounting for the specific features of different variants to avoid potential negative impacts on the economy.

Common Side Effects of Pfizer COVID-19 Vaccine: An Experience From Pakistan

Introduction The severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) epidemic spread quickly. Vaccines are now being distributed to stop the infectious spread and halt fatalities. The Pfizer-BioNTech vaccine was the first mRNA-based vaccine introduced to boost immunity against COVID-19; however, it could lead to various adverse reactions. Therefore, the aim of this study was to assess the prevalence of Pfizer vaccine side effects among participants. Methods This was a multicenter cross-sectional study that was performed using a non-probability sampling method. The study period was about six months from March 1, 2022, to August 31, 2022. A total of 1000 participants who received two doses of the Pfizer vaccine met the inclusion criteria. Demographic details of participants, for example, gender, age, comorbidities, Pfizer vaccine with both doses along with booster dose, previous exposure to coronavirus disease 2019 (COVID-19) infection, and the incidence of any local and systemic side effects following the first and second doses of vaccine, were reported.  Results The study findings showed that out of 1000 participants, 644 (64.4%) were males and 356 (35.6%) were females; their mean age was 43.06±14.98 years. Among them, 280 (28.0%) had hypertension and 356 (35.6%) had diabetes. Following the first dose of the Pfizer vaccine, burning at the injection site and fever were the most commonly reported side effects in 704 (70.4%) and 700 (70.0%) participants, respectively. Following the second dose of the Pfizer vaccine, muscle pain was the most commonly reported side effect in 628 (62.8%) participants. Conclusion This study concluded that the most frequent adverse effects of the Pfizer vaccine were burning at the injection site, fever, pain at the injection site, muscle pain, swelling at the injection site, and joint pain. Moreover, the first dose was associated with more side effects than the second dose.

The Evaluation of Web-Based Communication Interventions to Support Decisions About COVID-19 Vaccination Among Patients With Underlying Medical Conditions: Protocol for a Randomized Controlled Trial

BACKGROUND

The timeliness of raising vaccine acceptance and uptake among the public is essential to overcoming COVID-19; however, the decision-making process among patients with underlying medical conditions is complex, leading individuals to vaccine hesitancy because of their health status. Although vaccine implementation is more effective when deployed as soon as possible, vaccine hesitancy is a significant threat to the success of vaccination programs.

OBJECTIVE

This study aims to evaluate the effectiveness of a communication tool for patients with underlying medical conditions who should decide whether to receive a COVID-19 vaccine.

METHODS

This 3-arm prospective randomized controlled trial will test the effect of the developed communication intervention, which is fully automated, patient decision aid (SMART-DA), and user-centered information (SMART-DA-α). The web-based intervention was developed to help decision-making regarding COVID-19 vaccination among patients with underlying medical conditions. Over 450 patients will be enrolled on the web from a closed panel access website and randomly assigned to 1 of 3 equal groups stratified by their underlying disease, sex, age, and willingness to receive a COVID-19 vaccine. SMART-DA-α provides additional information targeted at helping patients' decision-making regarding COVID-19 vaccination. Implementation outcomes are COVID-19 vaccination intention, vaccine knowledge, decisional conflict, stress related to decision-making, and attitudes toward vaccination, and was self-assessed through questionnaires.

RESULTS

This study was funded in 2020 and approved by the Clinical Research Information Service, Republic of Korea. Data were collected from December 2021 to January 2022. This paper was initially submitted before data analysis. The results are expected to be published in the winter of 2023.

CONCLUSIONS

We believe that the outcomes of this study will provide valuable new insights into the potential of decision aids for supporting informed decision-making regarding COVID-19 vaccination and discovering the barriers to making informed decisions regarding COVID-19 vaccination, especially among patients with underlying medical conditions. This study will provide knowledge about the common needs, fears, and perceptions concerning vaccines among patients, which can help tailor information for individuals and develop policies to support them.

TRIAL REGISTRATION

Korea Clinical Information Service KCT0006945; https://cris.nih.go.kr/cris/search/detailSearch.do/20965.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/42837.

COVID-19 Outbreak in Daegu City, Korea and Response to COVID-19: How Have We Dealt and What Are the Lessons?

The first coronavirus disease 2019 (COVID-19) outbreak in Daegu city was overcome by efforts, including; 1) prompt isolation and quarantine action by local government with cooperative help from expert groups and the central government, 2) high-intensity social distancing and active cooperation of citizens, 3) admission of asymptomatic and mild patients in 'residential treatment centers', and 4) use of a telephone scoring system for the allocation of patients, with a mortality rate of 2.5%. A continuous suppression policy with test, tracing, and treatment (3 Ts) was implemented as an active response to the initial outbreaks in Korea. With the introduction of vaccines and therapeutic agents, the COVID-19 crisis had improved. Recently, the omicron variant was responsible for most domestic outbreaks, albeit with a low mortality rate (0.1%). Since the omicron outbreak, a damage mitigation policy has been implemented, focusing on protecting vulnerable groups. In the future, preparation including below are needed; 1) improving the national public health emergency response system, 2) strengthening the crisis response capacity of local governments, 3) cooperation between public healthcare and private healthcare, and 4) establishing a resilient medical response system.

Model-informed COVID-19 exit strategy with projections of SARS-CoV-2 infections generated by variants in the Republic of Korea

BACKGROUND

With the prompt administration of coronavirus disease 2019 (COVID-19) vaccines, highly vaccinated countries have begun to lift their stringent control measures. However, considering the spread of highly transmissible new variants, resuming socio-economic activities may lead to the resurgence of incidence, particularly in nations with a low proportion of individuals who have natural immunity. Here, we aimed to quantitatively assess an optimal COVID-19 exit strategy in the Republic of Korea, where only a small number of cumulative incidences have been recorded as of September 2021, comparing epidemiological outcomes via scenario analysis.

METHODS

A discrete-time deterministic compartmental model structured by age group was used, accounting for the variant-specific transmission dynamics and the currently planned nationwide vaccination. All parameters were calibrated using comprehensive empirical data obtained from the Korea Disease Control and Prevention Agency.

RESULTS

Our projection suggests that tapering the level of social distancing countermeasures to the minimum level from November 2021 can efficiently suppress a resurgence of incidence given the currently planned nationwide vaccine roll-out. In addition, considering the spread of the Delta variant, our model suggested that gradual easing of countermeasures for more than 4 months can efficiently withstand the prevalence of severe COVID-19 cases until the end of 2022.

CONCLUSIONS

Our model-based projections provide evidence-based guidance for an exit strategy that allows society to resume normal life while sustaining the suppression of the COVID-19 epidemic in countries where the spread of COVID-19 has been well controlled.

Maintenance of Antibody Response in Egyptian Healthcare Workers Vaccinated with ChAdOx1 nCoV-19 Vaccine during Delta and Omicron Variants Pandemic: A Prospective Study

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a constantly evolving virus, resulting in an increased burden on the existing COVID-19 vaccines. Healthcare workers (HCWs) are the first line of defense against the coronavirus disease 2019 (COVID-19) pandemic and have been prioritized among the risk categories receiving the COVID-19 vaccine. This work aimed to investigate the maintenance of antibody response of the Oxford−AstraZeneca vaccine (ChAdOx1/nCoV-19). Methods: Anti-spike immunoglobulin G (IgG) was measured at baseline point (immediately prior to vaccination) and 12- and 24-week (w) points following vaccination. Adverse reactions to the vaccine were reported. Participants were followed up for the incidence of COVID-19 during the 12 w interval between vaccination doses for 24 w after the second dose. Results: A total of 255 HCWs participated in the study. Prior to vaccination, 54.1% experienced COVID-19, 88.2% were seropositive after the first dose, while seropositivity reached 95.7% after the second dose. Following the first and second doses, the anti-spike IgG serum level was significantly higher in subjects with past COVID-19 than in others (p < 0.001 and =0.001, respectively). Conclusions: The Oxford−AstraZeneca vaccine is generally safe and provides a highly effective long-term humoral immune response against the Delta and Omicron variants of SARS-CoV-2.

Virtual autopsy in SARS-CoV-2 breakthrough infection: a case report

It is well documented that COVID-19 vaccines are effective tools for limiting the pandemic. Unfortunately, as is true for all vaccines, SARS-CoV-2 infection in vaccinated individuals is still possible.

We present an autopsy case of SARS-CoV-2 infection after vaccination (“breakthrough infection”) in an elderly man with several comorbidities where post-mortem CT scan was performed. The death was histologically attributed to cardio-respiratory arrest due to ischemic heart failure related to superinfected COVID-19 pneumonia and pre-existing comorbidities. For the first time in the literature, PMCT imaging related to a fatal, autopsy case of breakthrough SARS-CoV-2 infection is reported. PMCT of the lungs, in accordance with histopathological results, showed few signs of COVID-19 pneumonia, large area of consolidation in the right lower lobe, interpreted as bronco-pneumonic focus, and hypostasis.

These findings were well-correlated with the previously reported literature about both PMCT and clinical CT imaging of the lungs in non-vaccinated individuals with early COVID-19 pneumonia and about pulmonary clinical CT imaging in COVID-19 pneumonia in breakthrough SARS-COV-2 infections.

Further studies are needed to cover the whole spectrum of PMCT lung imaging in fatal breakthrough SARS-CoV-2 infection, however, this case represent a first step for exploring this difficult challenge during SARS-CoV-2 pandemic using virtual autopsy.

Pediatric Off-Label COVID-19 Vaccination: The Concerns of Healthcare Professionals in Pakistan

Global health authorities have emphasized the vital role of healthcare professionals (HCPs) as a reliable source of vaccination information for patients in primary care. However, HCPs are concerned whether COVID-19 vaccinations can be used off-label. Hence, the current study was conducted to assess their perspectives towards off-label COVID-19 immunization in children. The study tool, consisting of 40 items, was utilized to evaluate HCPs’ knowledge and attitudes towards the off-label use of the COVID-19 vaccine in children under 12 years of age. To assess the unfavorable attitudes regarding vaccinations, the Vaccination Attitudes Examination Scale was employed. Overall, 477 completed questionnaires were incorporated in the present study, with a response rate of 88.9%. The mean age of the respondents was 38.6 ± 7.5 years; among whom the majority were physicians, n = 209 (43.8%), and pharmacists, n = 112 (23.4%). Approximately 78% of the respondents had a general awareness of off-label vaccination. Around 80% knew the adverse drug reactions associated with the use of COVID-19 vaccines. Females showed more mistrust about vaccine benefits, n = 55 (16.9%), compared to males, n = 21 (13.8%), and concerns about commercial profits of vaccines, n = 59 (18.1%), compared to males, n = 19 (12.5%). By profession, physicians showed statistically significantly lower mistrust, n = 18 (8.6%), and higher concerns about unpredicted effects of vaccines, n = 41 (19.6%). A major portion of the respondents, n = 327 (68.5%), did not consider that HCPs should prescribe/administer off-label COVID-19 vaccination in children. The current findings demonstrated that respondents had an appropriate level of understanding about COVID-19 immunization in children. They showed higher levels of rejection for off-label use of the COVID-19 vaccination.

The Role of COVID-19 Vaccine Perception, Hope, and Fear on the Travel Bubble Program

The travel bubble program presented an appealing strategy for reopening international travel safely. However, a full vaccination regime is the foremost prerequisite of the program. Therefore, vaccination and the travel bubble are inextricably linked. This study investigated the roles of perceived vaccine efficacy, attitude towards the COVID-19 vaccine, and attitude toward the travel bubble on travel bubble intention. More importantly, the study also examined the mediating role of hope and fear among unvaccinated Korean adults between 20 and 29 years old. A total of 535 samples were collected to test the proposed conceptual model using structural equation modeling. In general, the results supported the proposed hypotheses. Notably, the intention to travel to a bubble destination was explained by 57% of the variance. Furthermore, hope mediated the relationship between vaccine attitude and travel bubble intention. Whereas fear mediated the relationship between perceived vaccine efficacy and intention. Hence, the findings suggest doubts around the vaccine efficacy and that a positive attitude towards the vaccine also install hope among the research samples.

Booster Vaccination Strategies for “Living With COVID-19”

Although the primary and secondary vaccination rates in Korea account for over 75% of the total population, confirmed cases of COVID-19 are dramatically increasing due to immune waning and the Omicron variant. Therefore, it is urgent to evaluate the effectiveness of booster vaccination strategies for living with COVID-19. In this work, we have developed an age-specific mathematical model with eight age groups and included age-specific comorbidities to evaluate the effectiveness of age-specific vaccination prioritization strategies to minimize morbidity and mortality. Furthermore, we have investigated the impacts of age-specific vaccination strategies for different vaccine supplies and non-pharmaceutical intervention levels during two periods: (1) when vaccine supply was insufficient and (2) after the emergence of the omicron variant. During the first period, the best option was to vaccinate the 30–49 year age group and the group with comorbidities to minimize morbidity and mortality, respectively. However, a booster vaccination should prioritize the 30–49 year age group to promote both minimal morbidity and mortality. Critical factors, such as vaccination speed, vaccine efficacy, and non-pharmaceutical interventions (NPIs), should be considered for effective vaccination prioritization as well. Primary, secondary vaccinations, and a booster shot vaccinations require different age prioritization strategies under different vaccination rates, vaccine efficacies, and NPI levels.

Imaging and Clinical Features of COVID-19 Breakthrough Infections: A Multicenter Study

Background Since vaccines against COVID-19 became available, rare breakthrough infections have been reported despite their high efficacies. Purpose To evaluate the clinical and imaging characteristics of patients with COVID-19 breakthrough infections and compare them with those of unvaccinated patients with COVID-19. Materials and Methods In this retrospective multicenter cohort study, the authors analyzed patient (aged ≥18 years) data from three centers that were registered in an open data repository for COVID-19 between June and August 2021. Hospitalized patients with baseline chest radiographs were divided into three groups according to their vaccination status. Differences between clinical and imaging features were analyzed using the Pearson χ2 test, Fisher exact test, and analysis of variance. Univariable and multivariable logistic regression analyses were used to evaluate associations between clinical factors, including vaccination status and clinical outcomes. Results Of the 761 hospitalized patients with COVID-19, the mean age was 47 years and 385 (51%) were women; 47 patients (6%) were fully vaccinated (breakthrough infection), 127 (17%) were partially vaccinated, and 587 (77%) were unvaccinated. Of the 761 patients, 412 (54%) underwent chest CT during hospitalization. Among the patients who underwent CT, the proportions without pneumonia were 22% of unvaccinated patients (71 of 326), 30% of partially vaccinated patients (19 of 64), and 59% of fully vaccinated patients (13 of 22) (P < .001). Fully vaccinated status was associated with a lower risk of requiring supplemental oxygen (odds ratio [OR], 0.24 [95% CI: 0.09, 0.64; P = .005]) and lower risk of intensive care unit admission (OR, 0.08 [95% CI: 0.09, 0.78; P = .02]) compared with unvaccinated status. Conclusion Patients with COVID-19 breakthrough infections had a significantly higher proportion of CT scans without pneumonia compared with unvaccinated patients. Vaccinated patients with breakthrough infections had a lower likelihood of requiring supplemental oxygen and intensive care unit admission. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Schiebler and Bluemke in this issue.

COVID-19 outbreak response at a nursing hospital in South Korea in the post-vaccination era, including an estimation of the effectiveness of the first shot of the Oxford-AstraZeneca COVID-19 vaccine (ChAdOx1-S)

Objectives

We descriptively reviewed a coronavirus disease 2019 (COVID-19) outbreak at a nursing hospital in Gyeonggi Province (South Korea) and assessed the effectiveness of the first dose of the Oxford-AstraZeneca vaccine in a real-world population.

Methods

The general process of the epidemiological investigation included a public health intervention. The relative risk (RR) of vaccinated and unvaccinated groups was calculated and compared to confirm the risk of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, and vaccine effectiveness was evaluated based on the calculated RR.

Results

The population at risk was confined to ward E among 8 wards of Hospital X, where the outbreak occurred. This population comprised 55 people, including 39 patients, 12 nurses, and 4 caregivers, and 19 cases were identified. The RR between the vaccinated and unvaccinated groups was 0.04, resulting in a vaccine effectiveness of 95.3%. The vaccination rate of the non-patients in ward E was the lowest in the entire hospital, whereas the overall vaccination rate of the combined patient and non-patient groups in ward E was the third lowest.

Conclusion

The first dose of the Oxford-AstraZeneca vaccine (ChAdOx1-S) was effective in preventing SARS-CoV-2 infection. To prevent COVID-19 outbreaks in medical facilities, it is important to prioritize the vaccination of healthcare providers.

Home-based rehabilitation in patients over 60 with stabilized ankylosing spondylitis during the COVID-19 pandemic

BACKGROUND

COVID-19 has become a significant healthcare issue, particularly challenging for patients with ankylosing spondylitis (AS), because immune-related diseases and their treatments could adversely affect the susceptibility to or severity of a viral infection.

OBJECTIVE

This study is conducted to present an exercise rehabilitation program that patients older than 60 years with AS can do at home during the COVID-19 pandemic.

METHODS

Three Delphi surveys were conducted to reach a consensus on home-based rehabilitation programs. This study recruited ten experts and performed three Delphi rounds for a month.

RESULTS

The expert panel suggested that home-based rehabilitation for the patients should be carried out with a clear rehabilitation goal. Their final recommendations are to institute a program aimed to ease symptoms, such as pain and stiffness; encourage patients to consult with experts regularly to ensure that they perform exercise rehabilitation properly at home; add fast walking and stretching to the rehabilitation program; and see if indoor cycling, Pilates, or yoga could be appropriate.

CONCLUSIONS

This study suggests that patients with AS over 60 should repeat low-intensity exercises, such as stretching, for an hour a day, four to six times a week during the COVID-19 pandemic.

Pfizer-BioNTech COVID-19 Vaccine (BNT162b2) Side Effects: A Systematic Review

Vaccinations prevented severe clinical complications of COVID-19. It was considered a vital component of living endemically with COVID-19. The Pfizer-BioNTech vaccine is the first mRNA-based vaccination that enhances immunity. Resulting in various adverse effects that may emerge after vaccination. This systematic review was undertaken to assess the Pfizer-BioNTech vaccine side effects by reviewing the previous studies. A total of 107 PubMed and Google Scholar publications were screened for Pfizer-BioNTech COVID-19 vaccine side effects. Fourteen articles met the study inclusion criteria. The included searching terms were a combination of "Pfizer vaccine and Side effects," "BioNTech vaccine and side effects," and "BNT162b2 vaccine and side effects," as well as all synonyms. The total number of participants in the 14 studies was 10,632 participants. Average of the most frequent side effects of 14 studies were injection site pain 77.34%, fatigue 43%, muscle pain 39.67%, local swelling 33.57%, headache 33.27%, joint pain 25.75%, chills 18.34%, fever 18%, itching 9.38%, lymph nodes swelling 7.86%, nausea 7.58%, dyspnea 7.86%,and diarrhea 6.36%. The average side effects after the first dose were 79% compared with 84% after the second dose. The average occurs side effects in females at 69.8% compared with males 30.2%. Our study reveals that side effects after the Pfizer-BioNTech vaccine are common, but they are usually mild and self-limited. Local reactions like pain at the injection site are the most common. Anaphylactic shock or severe reactions are rare. We hope that our results will reassure the public that the benefits of vaccination far exceed the dangers. Also, help reduce vaccine hesitancy among individuals worried about vaccine safety and possible adverse effects.

Healthcare Workers in South Korea Maintain a SARS-CoV-2 Antibody Response Six Months After Receiving a Second Dose of the BNT162b2 mRNA Vaccine

Background

Effective vaccines against coronavirus disease 2019 (COVID-19) are available worldwide; however, the longevity of vaccine effectiveness is not known.

Objective

We performed a prospective observational study to assess the antibody response of healthcare workers against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after BNT162b2 mRNA COVID-19 vaccination.

Methods

SARS-CoV-2 neutralizing antibody (nAb) and spike (S) protein-IgG (S-IgG) antibody titers were examined in participants who received two doses of the BNT162b2 mRNA COVID-19 vaccine in a single center between March 1, 2021, and October 11, 2021. Antibody levels were analyzed at four times: before vaccination (visit 1), 4 weeks after the first vaccination (visit 2), 3 months after the second vaccination (visit 3), and 6 months after the second vaccination (visit 4).

Results

A total of 249 healthcare workers at Jeju National University Hospital were enrolled in this study, and 982 blood samples were analyzed. The mean age was 38.1 ± 9.5 years, and 145 (58.2%) participants were females. Positive nAbs (inhibition rates ≥ 20%) were measured in 166/249 (66.7%) subjects at visit 2, 237/243 (97.5%) subjects at visit 3, and 150/237 (63.3%) subjects at visit 4. A S-IgG (≥50 AU/mL) positivity was detected in 246/249 (98.8%) subjects at visit 1, and all participants had positive S-IgG antibody levels at visits 3 and 4 after being fully vaccinated. Further analysis of S-IgG levels revealed a median quantitative antibody level of 1275.1 AU/mL (interquartile range [IQR] 755.5–2119.0) at visit 2, 2765.9 AU/mL (IQR 1809.8–4138.4) at visit 3, and 970.1 AU/mL (IQR 606.0–1495.9) at visit 4. Patient characteristics, such as age, body mass index, and comorbidity, had no relationship with nAb or S-IgG levels at any of the visits. Considering the change in antibody levels over time, both nAb and S-IgG levels at visit 4 decreased compared with the corresponding levels at visit 3. No evidence of SARS-CoV-2 infection was found among any of the participants throughout the study.

Conclusions

The BNT162b2 mRNA vaccine was effective in protecting healthcare personnel working in COVID-19-related departments. While the level of S-IgG antibodies was maintained for 6 months after the second vaccination, nAb levels waned over this 6-month period, indicating the need for a booster vaccination in some healthcare workers 6 months after full vaccination. Herein, we suggest that further studies are needed to evaluate the need for an interval of booster vaccination after full vaccination.

Comparing SARS-CoV-2 Antibody Responses after Various COVID-19 Vaccinations in Healthcare Workers

Coronavirus disease 2019 (COVID-19) vaccination began for healthcare workers in South Korea at the end of February 2021. This study investigated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses after various COVID-19 vaccinations in healthcare workers. Blood specimens of 497 vaccinated healthcare workers were collected. Inoculated vaccines were ChAdOx1 (AstraZeneca/Oxford), BNT162b2 (Pfizer/BioNTech), JNJ-78436735 (Janssen), and mRNA-1273 (Moderna). Each specimen was tested for antibodies against SARS-CoV-2 using Elecsys Anti-SARS-CoV-2 S assay (Roche Diagnostics), SARS-CoV-2 IgG II Quant assay (Abbott), and R-FIND SARS-CoV-2 Neutralizing Antibody kit (SG medical Inc.). A questionnaire was used to investigate adverse events related to vaccination. We found that 99.5% of the subjects showed a 96–100% positive rate in all three antibody assays, regardless of the vaccine type. The antibody-positive rate of completed vaccination groups reached 96–100%, and antibody quantities significantly increased 2 weeks after vaccination. The antibody values measured approximately 3 months after BNT162b2 inoculation significantly correlated with adverse events.

Analyses of Confirmed COVID-19 Cases Among Korean Military Personnel After Mass Vaccination

BACKGROUND

The military was one of the first groups in Korea to complete mass vaccination against the coronavirus disease 2019 (COVID-19) due to their high vulnerability to COVID-19. To confirm the effect of mass vaccination, this study analyzed the patterns of confirmed cases within Korean military units.

METHODS

From August 1 to September 15, 2021, all epidemiological data regarding confirmed COVID-19 cases in military units were reviewed. The number of confirmed cases in the units that were believed to have achieved herd immunity (i.e., ≥ 70% vaccination) was compared with the number of cases in the units that were not believed to have reached herd immunity (< 70% vaccination). Additionally, trends in the incidence rates of COVID-19 in the military and the entire Korean population were compared.

RESULTS

By August 2021, 85.60% of military personnel were fully vaccinated. During the study period, a total of 174 COVID-19 cases were confirmed in the 39 units. More local transmission (herd immunity group vs. non-herd immunity group [%], 1 [0.91] vs. 39 [60.94]) and hospitalizations (12 [11.01] vs. 13 [27.08]) occurred in the units that were not believed to have achieved herd immunity. The percentage of fully vaccinated individuals among the confirmed COVID-19 cases increased over time, possibly due to the prevalence of the delta variant. Nevertheless, the incidence rate remained lower in military units than in the general Korean population.

CONCLUSION

After completing mass vaccination, the incidence rates of COVID-19 infection in the military were lower than those in the national population. New cluster infections did not occur in vaccinated units, thereby suggesting that herd immunity has been achieved in these military units. Further research is needed to determine the extent to which levels of non-pharmacological intervention can be reduced in the future.

Adverse Events with the Pfizer-BioNTech COVID-19 Vaccine among Korean Healthcare Workers

The Pfizer-BioNTech COVID-19 vaccine has shown excellent clinical effectiveness; however, adverse events of the vaccine remain a concern in Korea. We surveyed adverse events in 2498 healthcare workers vaccinated with the Pfizer-BioNTech COVID-19 vaccine at a university hospital. The survey was conducted using a diary card for 7 days following each injection. The questionnaire response rate was 75.1% (1876/2498) for the first dose and 73.8% (1840/2493) for the second dose. Among local reactions, pain was the most commonly reported (84.9% after the first dose and 90.4% after the second dose). After the second dose, two people visited the emergency room due to severe local pain, but no hospitalization or skin necrosis occurred. Among systemic reactions, fatigue was most frequently reported (52.8% after the first dose and 77.0% after the second dose), followed by myalgia (49.0% and 76.1%), headache (28.7% and 59.2%), chills (16.7% and 54.0%), and arthralgia (11.4% and 39.2%). One or more critical adverse events occurred in 0.2% and 0.7% of the vaccinees. Except for urticaria, more adverse events were reported after the second dose than after the first dose. In the future, adverse events should be investigated in older adults, and a future study with a longer observation period should be conducted.

Comparison of Antibody Response Elicited by ChAdOx1 and BNT162b2 COVID-19 Vaccine

BACKGROUND

ChAdOx1 and BNT162b2 vaccines are currently commonly used against coronavirus disease 2019 worldwide. Our study was designed to determine the serostatus and relative levels of anti-S and neutralizing antibodies in patients who were administered either ChAdOx1 or BNT162b2 vaccine. In addition, we investigated whether the antibody response to each vaccine differed according to sex and age.

METHODS

Healthcare workers (HCWs) at a general hospital who were vaccinated with two doses of either ChAdOx1 or BNT162b2 were invited to participate in this prospective cohort study. Blood samples of HCWs vaccinated with both ChAdOx1 doses over a period of 12 weeks were collected at weeks 4 and 8 post first vaccination and 2 weeks post second vaccination. Blood samples of HCWs vaccinated with BNT162b2 were collected in the third week after the first dose, and the second dose was then administered on the same day; two weeks post second dose (5 weeks after the first dose), blood samples were collected to assess the antibody response. The titers of anti-S antibodies against the severe acute respiratory syndrome coronavirus 2 spike (S) protein receptor-binding domain and the neutralizing antibodies in the collected blood were evaluated.

RESULTS

Of the 309 HCWs enrolled in the study, 205 received ChAdOx1 and 104 received BNT162b2. Blood samples from participants receiving either the ChAdOx1 or BNT162b2 vaccine exhibited substantial anti-S and neutralizing antibody seropositivity subsequent to the second dose. All participants (100%) from both vaccine groups were seropositive for anti-S antibody, while 98% (201/205) of ChAdOx1-vaccinated individuals and 100% (104/104) of BNT162b2-vaccinated individuals were seropositive for neutralizing antibodies. The median levels of anti-S and neutralizing antibodies were significantly higher in the BNT162b2-vaccinated group than the ChAdOx1-vaccinated group; in particular, anti-S antibody titers of 1,020 (interquartile range, 571.0-1,631.0) U/mL vs. 2,360 (1,243-2,500) U/mL, P < 0.05, were recorded for the ChAdOx1 and BNT162b2 groups, respectively, and neutralizing antibody titers of 85.0 (65.9-92.1%) vs. 95.8 (94.4-96.6%), P < 0.05, were recorded for the ChAdOx1 and BNT162b2 groups, respectively. In the ChAdOx1 vaccine group, the neutralizing antibody level was significantly higher in women than in men (85.7 [70.3-92.5%] vs. 77.7 [59.2-91.0%], P < 0.05); however, the neutralizing antibody titer in the BNT162b2 vaccine group did not vary between the two sexes (95.9 [95.2-96.6%] vs. 95.2 [93.5-96.3%], P = 0.200). Analysis of the correlation of antibody profiles with age revealed that the levels of anti-S antibodies and signal inhibition rate (SIR) of neutralizing antibodies decreased significantly with age.

CONCLUSION

Both the ChAdOx1- and BNT162b2-vaccinated groups showed high seropositivity for anti-S and neutralizing antibodies. The SIR of neutralizing antibodies in the ChAdOx1 vaccine group was higher in women than in men. Enhanced antibody responses were observed in participants vaccinated with BNT162b2 compared to those vaccinated with the ChAdOx1 vaccine.

Direct and Indirect Associations of Media Use with COVID-19 Vaccine Hesitancy: Cross-sectional Web-Based Survey in South Korea

BACKGROUND

Background: The battle against the 2019 novel coronavirus (COVID-19) has not concluded. Although vaccines are available, the high prevalence of vaccine hesitancy represents a significant challenge to public health and raising vaccine acceptance among the public is critical. While media has become an increasingly popular source of COVID-19 vaccine-related information, the question of whether and how media use is related to the public's vaccine hesitancy warrants exploration.

OBJECTIVE

This study aimed to (1) examine the level of COVID-19 vaccine hesitancy, (2) identify factors associated with COVID-19 vaccine hesitancy, and (3) explore the direct and indirect relationship between media use and vaccine hesitancy through psychological factors.

METHODS

A cross-sectional online survey took place over six days (January 20-25, 2021), a month ago before COVID-19 vaccination was initiated in South Korea. This study included 1016 subjects, and a logit model for regression analyzed associations between socio-demographic factors, health-related factors, psychological factors, and media use toward one's COVID-19 vaccine hesitancy. Additionally, path analysis to examine the indirect effects of media use on vaccine hesitancy via psychological factors (i.e., perceived risk of COVID-19 infection, perceived benefits, and perceived barriers of COVID-19 vaccination) were conducted.

RESULTS

Among the respondents (n=1,016), 53.3% hesitated COVID-19 vaccination, while 46.7% of the respondents would accept the vaccine. Out of the socio-demographic factors, female (OR, 1.967; 95% CI, 1.36-2.86; P < .001), age in 50s (OR, .47; 95% CI, .23-.96; P= .004), and over 60s (OR, .49; 95% CI, .24 - 0.99; P= .04) were significant individual predictors of COVID-19 vaccine hesitancy. Perceived susceptibility of infection (OR, .69; 95% CI, .52 - .91; P= .01) and perceived benefits of vaccination (OR, .69; 95% CI, .52 - .91; P= .01) were associated with lower vaccine hesitancy. Perceived barriers of vaccination (OR, 1.63; 95% CI, 1.29 - 2.07; P < .001) and lower trust in government (OR, .72; 95% CI, .53 - 0.98; P= .04) were related to vaccine hesitancy. The use of offline and online media was associated with vaccine hesitancy through perceived benefits of vaccination, resulting in a lower vaccine hesitancy. Moreover, perceived susceptibility of the disease and perceived barriers of vaccination mediated the association between social media use and vaccine hesitancy.

CONCLUSIONS

Findings revealed a considerable level of COVID-19 vaccine hesitancy in South Korea. Gender-based and generation-based public health policies and communication are recommended. Efforts to lower the perceived risk of vaccine side effects and heighten perceived benefits of the vaccine are required. While the use of media has a positive or negative effect on the population's vaccine hesitancy, efforts should be made to disseminate reliable and timely information on media while confront misinformation or disinformation for successive implementation of vaccine programs during pandemics.

CLINICALTRIAL

Optimizing planning and design of COVID-19 drive-through mass vaccination clinics by simulation

Drive-through clinics have previously been utilized in vaccination efforts and are now being more widely adopted for COVID-19 vaccination in different parts of the world by offering many advantages including utilizing existing infrastructure, large daily throughput and enforcing social distancing by default. Successful, effective, and efficient drive-through facilities require a suitable site and keen focus on layout and process design. To demonstrate the role that high fidelity computer simulation can play in planning and design of drive-through mass vaccination clinics, we used multiple integrated discrete event simulation (DES) and agent-based modelling methods. This method using AnyLogic simulation software to aid in planning, design, and implementation of one of the largest and most successful early COVID-19 mass vaccination clinics operated by UCHealth in Denver, Colorado. Simulations proved to be helpful in aiding the optimization of UCHealth drive through mass vaccination clinic design and operations by exposing potential bottlenecks, overflows, and queueing, and clarifying the necessary number of supporting staff. Simulation results informed the target number of vaccinations and necessary processing times for different drive through station set ups and clinic formats. We found that modern simulation tools with advanced visual and analytical capabilities to be very useful for effective planning, design, and operations management of mass vaccination facilities.

Likelihood of COVID-19 vaccination by subgroups across the US: post-election trends and disparities

The coronavirus disease 2019 (COVID-19) pandemic has disproportionately impacted older individuals, those with lower educational attainment, and Black and Hispanic populations, yet vaccine hesitancy remains prevalent. Because widespread uptake of COVID-19 vaccines is critical to end the pandemic, addressing vaccine hesitancy is an important public health priority. Between April 1, 2020 and March 16, 2021, we have repeatedly surveyed a nationally representative online panel of adults and have tracked their stated likelihood of getting COVID-19 vaccinations. We present new evidence that in recent months disparities in self-reported likelihood of COVID-19 vaccination have narrowed by race/ethnicity, with an increasing proportion of Black individuals and Hispanic individuals indicating that they are likely to get a vaccine. At the same time, younger adults have progressively become less likely than older adults to state they will get a COVID-19 vaccine. Most vaccine-hesitant individuals are concerned about both vaccine efficacy and safety and do not trust the vaccine development or vaccine approval process. We conclude that outreach efforts to minority populations may be achieving their objectives in raising confidence in COVID-19 vaccines, but special outreach efforts are needed to address both vaccine hesitancy among younger adults and mistrust in the vaccine development and approval process.

Why Fast COVID-19 Vaccination Needed for People with Disabilities and Autistics in Korea?

Coronavirus disease 2019 (COVID-19) has negatively affected the lives of people with disabilities; therefore, they need fast vaccination allocation. However, many countries, especially the Republic of Korea, have hesitated to vaccinate people with disabilities. This opinion article will explain why vaccine allocation priority is required for autistic people and people with disabilities in the COVID-19 pandemic crisis, including reporting on self-quarantine's stresses and psychological burdens.

COVID-19 vaccines: Current evidence and considerations

The coronavirus disease 2019 (COVID-19) pandemic is a global crisis, with devastating health, business and social impacts. Vaccination is a safe, simple, and effective way of protecting a person against COVID-19. By the end of August 2021, only 24.6% of the world population has received two doses of a COVID-19 vaccine. Since the emergence of COVID-19, several COVID-19 vaccines have been developed and approved for emergency use. Current vaccines have shown efficacy with low risk of adverse effects. However, COVID-19 vaccines have been related to a relatively small number of cases of heart inflammation, anaphylaxis (allergic reactions), and blood clots formation. On the other hand, COVID-19 vaccination is not recommended for children less than 12 years of age. Furthermore, It has been proposed that some new variants (e.g., Lambda and Delta) are proficient in escaping from the antiviral immunity elicited by vaccination. Herein we present current considerations regarding the COVID-19 vaccines including: efficacy against new variants, challenges in distribution, disparities in availability, dosage gender and race difference, COVID-19 vaccine transport and storage, limitations in children and pregnant women. Long-time monitoring is essential in order to find vaccine efficacy and to rule out related side effects.

COVID-19 Vaccine Perception in South Korea: Web Crawling Approach

BACKGROUND

The US Centers for Disease Control and Prevention and the World Health Organization emphasized vaccination against COVID-19 because physical distancing proved inadequate to mitigate death, illness, and massive economic loss.

OBJECTIVE

This study aimed to investigate Korean citizens' perceptions of vaccines by examining their views on COVID-19 vaccines, their positive and negative perceptions of each vaccine, and ways to enhance policies to increase vaccine acceptance.

METHODS

This cross-sectional study analyzed posts on NAVER and Instagram to examine Korean citizens' perception of COVID-19 vaccines. The keywords searched were "vaccine," "AstraZeneca," and "Pfizer." In total 8100 posts in NAVER and 5291 posts in Instagram were sampled through web crawling. Morphology analysis was performed, overlapping or meaningless words were removed, sentiment analysis was implemented, and 3 public health professionals reviewed the results.

RESULTS

The findings revealed a negative perception of COVID-19 vaccines; of the words crawled, the proportion of negative words for AstraZeneca was 71.0% (476/670) and for Pfizer was 56.3% (498/885). Among words crawled with "vaccine," "good" ranked first, with a frequency of 13.43% (312/2323). Meanwhile, "side effect" ranked highest, with a frequency of 29.2% (163/559) for "AstraZeneca," but 0.6% (4/673) for "Pfizer." With "vaccine," positive words were more frequently used, whereas with "AstraZeneca" and "Pfizer" negative words were prevalent.

CONCLUSIONS

There is a negative perception of AstraZeneca and Pfizer vaccines in Korea, with 1 in 4 people refusing vaccination. To address this, accurate information needs to be shared about vaccines including AstraZeneca, and the experiences of those vaccinated. Furthermore, government communication about risk management is required to increase the AstraZeneca vaccination rate for herd immunity before the vaccine expires.

COVID-19 vaccine safety monitoring in the Republic of Korea: February 26, 2021 to April 30, 2021

Objectives

On February 26, 2021, coronavirus disease 2019 (COVID-19) vaccination was started for high-priority groups based on the recommendation of the Advisory Committee on Immunization Practices with 2 available COVID-19 vaccines (AstraZeneca and Pfizer-BioNTech) in Korea. This report provides a summary of adverse events following COVID-19 vaccination as of April 30, 2021.

Methods

Adverse events following immunization are notifiable by medical doctors to the Korea Immunization Management System (KIMS) under the national surveillance system. We analyzed all adverse events reports following COVID-19 vaccination to the KIMS from February 26 to April 30, 2021.

Results

In total, 16,196 adverse events following 3,586,814 administered doses of COVID-19 vaccines were reported in approximately 2 months (February 26 to April 30, 2021). Of these, 15,658 (96.7%) were non-serious adverse events, and 538 (3.3%) were serious adverse events, including 73 (0.5%) deaths. The majority of adverse events (n=13,063, 80.7%) were observed in women, and the most frequently reported adverse events were myalgia (52.2%), fever (44.9%), and headache (34.9%). Of the 73 deaths following the COVID-19 vaccination, none were related to the vaccines.

Conclusion

By April 30, 3.6 million doses of the COVID 19 vaccine had been given in Korea, and the overwhelming majority of reports were for non-serious events. The Korea Disease Control and Prevention Agency continues to monitor the safety of COVID-19 vaccination.

Early Adverse Events between mRNA and Adenovirus-Vectored COVID-19 Vaccines in Healthcare Workers

Mass vaccination campaigns are important to control the COVID-19 pandemic, however, adverse events (AEs) contribute to vaccine hesitancy. To investigate and compare early AEs between the BNT162b2 mRNA and AZD1222 adenovirus-vectored vaccines, recipients completed daily surveys about local and systemic reactions for 7 days after each dose, respectively. A total of 80 and 1440 healthcare workers received two doses of BNT162b2 and a first dose of AZD1222 vaccines. Any AEs were reported by 52.5% of recipients after the first dose of BNT162b2, by 76.2% after the second dose of BNT162b2, and by 90.9% after the first dose of AZD1222 (p < 0.001). Younger vaccinees had more AEs after the second dose of BNT162b2 and first dose of AZD1222. Sex based differences were only observed in the AZD1222 recipient group. No incidence of anaphylaxis or neurologic AEs were observed. In conclusion, early AEs were mostly mild to moderate in severity and generally transient in both BNT162b2 and AZD1222 groups. Sufficient explanation of the expected AEs of the vaccine would be helpful for wider vaccination.

Machine Learning Approach for Active Vaccine Safety Monitoring

BACKGROUND

Vaccine safety surveillance is important because it is related to vaccine hesitancy, which affects vaccination rate. To increase confidence in vaccination, the active monitoring of vaccine adverse events is important. For effective active surveillance, we developed and verified a machine learning-based active surveillance system using national claim data.

METHODS

We used two databases, one from the Korea Disease Control and Prevention Agency, which contains flu vaccination records for the elderly, and another from the National Health Insurance Service, which contains the claim data of vaccinated people. We developed a case-crossover design based machine learning model to predict the health outcome of interest events (anaphylaxis and agranulocytosis) using a random forest. Feature importance values were evaluated to determine candidate associations with each outcome. We investigated the relationship of the features to each event via a literature review, comparison with the Side Effect Resource, and using the Local Interpretable Model-agnostic Explanation method.

RESULTS

The trained model predicted each health outcome of interest with a high accuracy (approximately 70%). We found literature supporting our results, and most of the important drug-related features were listed in the Side Effect Resource database as inducing the health outcome of interest. For anaphylaxis, flu vaccination ranked high in our feature importance analysis and had a positive association in Local Interpretable Model-Agnostic Explanation analysis. Although the feature importance of vaccination was lower for agranulocytosis, it also had a positive relationship in the Local Interpretable Model-Agnostic Explanation analysis.

CONCLUSION

We developed a machine learning-based active surveillance system for detecting possible factors that can induce adverse events using health claim and vaccination databases. The results of the study demonstrated a potentially useful application of two linked national health record databases. Our model can contribute to the establishment of a system for conducting active surveillance on vaccination.

The hindrances to perform the COVID-19 vaccination in Brazil

INTRODUCTION

Brazil is one of the epicenters of COVID-19 pandemic and faces several hindrances to make his COVID-19 vaccination plan efficient.

METHODS

The Brazilian COVID-19 vaccination plan was evaluated and the hindrances to make the COVID-19 vaccination plan efficient were described and discussed.

RESULTS

High territorial extension might contribute to a delay on the COVID-19 vaccination, due to difficulty in delivering vaccines to furthest Brazilian states and to all the interior cities. The choice among the vaccines should be done based on the type of storage and must consider the transport conditions necessary to maintain its effectiveness. The indigenous individuals were included with health-care workers as the first group to be vaccinated, inflaming the number of vaccines doses distributed in states where the indigenous population have higher prevalence. The antivaccine movement and the politicization of the vaccine are also hindrances to be overcome in Brazil. The COVID-19 incidence or mortality rate and the distribution of intensive care units (ICUs) are not a criterion to distribute the vaccines, as we did not identify a correlation between these markers and the number of vaccines. However, a strong or very strong correlation occurred between the number of COVID-19 vaccines and the number of COVID-19 cases, deaths by COVID-19, gross domestic product, as well as populational density. A total of 83,280,475 doses of COVID-19 vaccines were distributed in Brazil. In the first dose, the Coronavac (Sinovac™), AZD1222 (AstraZeneca/Oxford™), and BNT162b (Pfizer/BioNTech™) vaccines were responsible to vaccinate, respectively, 9.61%, 6.69%, and 0.35% of the Brazilian population. In the second dose, the Coronavac, AZD1222, and BNT162b vaccines were responsible to vaccinate, respectively, 7.52%, 0.53%, and <0.01% of the Brazilian population.

CONCLUSIONS

The Federal Government must evaluate the hindrances and propose solutions to maximize the immunization against COVID-19 on Brazil.

Safety of the ChAdOx1 nCoV-19 and the BBV152 vaccines in 724 patients with rheumatic diseases: a post-vaccination cross-sectional survey

Patients with rheumatic and musculoskeletal (RMD) diseases may be at higher risks for COVID-19 infection. Data on the safety of the adenoviral vector-borne ChAdOx1 nCoV-19 and the heat-inactivated BBV152 Vaccines in this group are limited. 724 patients with RMD who had received at least one dose of either the ChAdOx1 or the BBV152 were audited to find out post-vaccination adverse effect (AE) or disease flares. The AE rates in patients with autoimmune rheumatic disease (AIRD) were compared with those with non-AIRD RMDs. The mean age of the cohort was 59.9 (± 10.43) years with a female (n = 581; 80.24%) majority. 523 (70.8%) had AIRD. The ChAdOx1 and the BBV152 vaccines were received by 624 (86.18%) and 77 (10.63%), respectively. 23 (3.17%) were unaware of which vaccine they had received. 238 (32.87%) of patients had at least one comorbidity. 436 (60.22%) participants [306 (59.64%) of those with AIRD and 130 (61.61%) with other RMDs] had at least one adverse effect (AE). Four patients reported flare of arthritis that resolved within 5 days. No patient had any severe AE or required hospitalization. All AEs were self-limiting. Both the ChAdOx1 and the BBV152 vaccines appear safe in RMDs. AEs do not differ between patients with AIRD or non-AIRD. This information can help negate vaccine hesitancy amongst all stakeholders.

COVID-19 Pandemic and Equal Access to Vaccines

The COVID-19 pandemic has evidenced the chronic inequality that exists between populations and communities as regards global healthcare. Vaccination, an appropriate tool for the prevention of infection, should be guaranteed by means of proportionate interventions to defeat such inequality in populations and communities affected by a higher risk of infection. Equitable criteria of justice should be identified and applied with respect to access to vaccination and to the order in which it should be administered. This article analyzes, as regards the worldwide distribution of anti-COVID-19 vaccines, the various ways the principle of equity has been construed and applied or even overlooked. The main obstacle to equal access to vaccines is vaccine nationalism. The perception of equity varies with the differing reference values adopted. Adequate response to needs appears to be the principal rule for achieving the criterion of equity in line with distributive justice. Priorities must be set equitably based on rational parameters in accordance with current needs. The entire process must be governed by transparency, from parameter identification to implementation. The issue of equal access to vaccination affects the entire world population, necessitating specific protective interventions. In light of this, the World Health Organization (WHO) has devised the COVAX plan to ensure that even the poorest nations of the world receive the vaccine; certain initiatives are also supported by the European Union (EU). This pandemic has brought to the fore the need to build a culture of equitable relationships both in each country’s own domain and with the rest of the world.

The urgency of vaccination against Covid-19 in dentists

The requirement of vaccines for the prevention of Covid-19 has become one of the health priorities of different countries worldwide (1, 2). However, most societies still do not have the necessary number of vaccines to cover their entire target population (3, 4). This is especially true in countries that delayed negotiations with the supply companies, and which will, unfortunately, have to wait a long time for the arrival of sufficient quantities to protect their populations. On theother hand, the global vaccination process has established priority levels among its citizens, specifically starting with the so-called first line of action that is health professionals attending Covid-19 patients, due to the great risk to which they are exposed. Additionally, the health organizations of the different countries have proposed to continue the vaccination process according to different criteria, one being the risk levels of the professions. This criterion is aimed at prioritizing professionals most exposed to contagion, but according to their daily practice, what professionals are really the most exposed to contagion?