A study of COVID-19 vaccination in the US and Asia: The role of media, personal experiences, and risk perceptions

The COVID-19 pandemic presents an opportunity to assess the relationship between personal experiences and vaccine decision-making. The aim of this study was to examine the associations between experiences with COVID-19 and COVID-19 vaccination status. We administered 28 repeated cross-sectional, online surveys between June 2020 and June 2021 in the US and Asia. The main exposure was media showing COVID-19 cases, and we distinguished those with no such experience, those seeing a not severe case of disease, and those seeing a severe case of disease. Logistic regression models estimated the association between experience and acceptance of a hypothetical COVID-19 vaccine (pre-rollout) or actual vaccination (post-rollout). We explored perceived susceptibility as a potential mediator. Intent to vaccinate was lowest in the US and Taiwan, and highest in India, Indonesia, and China. Across all countries, seeing a severe case of COVID-19 in the media was associated with 1.72 times higher odds of vaccination intent in 2020 (95% CI: 1.46, 2.02) and 2.13 times higher odds of vaccination in 2021 (95% CI: 1.70, 2.67), compared to those not seeing a case or a less severe case. Perceived susceptibility was estimated to mediate 25% of the relationship with hypothetical vaccination (95% CI: 18%, 31%, P<0.0001), and 16% of the relationship with actual vaccination 16% (95% CI: 12%, 19%, P<0.0001). Seriousness of experiences could relate to intention to vaccinate against COVID-19. Media exposures are a modifiable experience, and this study highlights how this experience can relate to risk perceptions and eventual vaccination, across a variety of countries where the course of the pandemic differed.

Long-term immune responses in patients with confirmed novel coronavirus disease-2019: a 9-month prospective cohort study in Shanghai, China.

BACKGROUND: The duration of antibodies against SARS-CoV-2 in Covid-19 patients remains uncertain. Longitudinal serological studies are needed to prevent disease and transmission of the virus. METHODS: In 2020, 414 blood samples were tested, obtained from 157 confirmed Covid-19 patients, in a prospective cohort study in Shanghai. RESULTS: The seropositive rate of IgM peaked at 40.5% (17/42) within 1 month after illness onset and then declined. The seropositive rate of IgG was 90.6% (58/64) after 2 months, remained above 85% from 2 to 9 months and was 90.9% (40/44) after 9 months. Generalized estimating equations models suggested that IgM (P < 0.001) but not IgG significantly decreased over time. Age ≥ 40 years (adjusted odds ratio [aOR] 4.531; 95% confidence interval [CI] 1.879-10.932), and cigarette smoking (aOR 0.344; 95% CI 0.124-0.951) were associated with IgG, and age ≥ 40 years (aOR 2.820; 95% CI 1.579-5.036) was associated with IgM. After seroconversion, over 90% and 75.1% of subjects were estimated to remain IgG-positive 220 and 254 days, respectively. Of 1420 self-reported symptoms questionnaires, only 5% reported symptoms 9 months after onset. CONCLUSIONS: In patients with a history of natural infection, anti-SARS-CoV-2 IgG is long-lived, being present for at least 9 months after illness onset. The long duration of natural immunity can mitigate and eliminate Covid-19 and the ongoing pandemic.

Effects of vaccination and non-pharmaceutical interventions and their lag times on the COVID-19 pandemic: Comparison of eight countries.

Many countries implemented measures to control the COVID-19 pandemic, but the effects of these measures have varied greatly. We evaluated the effects of different policies, the prevalence of dominant variants (e.g., Delta), and vaccination on the characteristics of the COVID-19 pandemic in eight countries. We quantified the lag times of different non-pharmaceutical interventions (NPIs) and vaccination using a distributed lag non-linear model (DLNM). We also tested whether these lag times were reasonable by analyzing changes in daily cases and the effective reproductive number (Rt)over time. Our results indicated that the response to vaccination in countries with continuous vaccination programs lagged by at least 40 days, and the lag time for a response to NPIs was at least 14 days. A rebound was most likely to occur during the 40 days after the first vaccine dose. We also found that the combination of school closure, workplace closure, restrictions on mass gatherings, and stay-at-home requirements were successful in containing the pandemic. Our results thus demonstrated that vaccination was effective, although some regions were adversely affected by new variants and low vaccination coverage. Importantly, relaxation of NPIs soon after implementation of a vaccination program may lead to a rebound.

Changes in COVID-19 risk perceptions: methods of an internet survey conducted in six countries.

OBJECTIVES: This study assessed changes in behaviors/attitudes related to the COVID-19. With the understanding that behaviors and vaccine decision-making could contribute to global spread of infectious diseases, this study collected several waves of internet-based surveys from individuals in the United States, mainland China, Taiwan, Malaysia, Indonesia, and India. The aims of this study were to (1) characterize the relationship between the epidemiology of disease and changes over time in risk perceptions, knowledge, and attitudes towards hygienic behaviors; (2) examine if risk perceptions affect acceptance of less-than-ideal vaccines; and (3) contrast adherence to public health recommendations across countries which have had different governmental responses to the outbreak. DATA DESCRIPTION: We conducted cross-sectional online surveys in six countries from March 2020 to April 2021. By the end of June 2021, there will be six waves of surveys for the United States and China, and four waves for the rest of countries. There are common sets of questions for all countries, however, some questions were adapted to reflect local situations and some questions were designed intentionally for specific countries to capture different COVID-19 mitigation actions. Participants were asked about their adherence towards countermeasures, risk perceptions, and acceptance of a hypothetical vaccine for COVID-19.

Would COVID-19 vaccination willingness increase if mobile technologies prohibit unvaccinated individuals from public spaces? A nationwide discrete choice experiment from China.

BACKGROUND: Achieving COVID-19 community protection (aka, herd immunity) in China may be challenging because many individuals remain unsure or are unwilling to be vaccinated. One potential means to increase COVID-19 vaccine uptake is to essentially mandate vaccination by using existing mobile technologies that can prohibit unvaccinated individuals from certain public spaces. The "Health Code" is a ubiquitous mobile phone app in China that regulates freedom of travel based on individuals' predicted risk of exposure to SARS-CoV-2. Green-colored codes indicate ability to travel unrestricted in low-risk regions; yellow-colored codes indicate prohibition from major public spaces and modes of public transportation. We examined the effects of a "Health Code"-based vaccine mandate on willingness to vaccinate for COVID-19 in China. METHODS: In August 2020, an online discrete choice experiment (DCE) was conducted among adults living in China. Participants completed up to six DCE choice sets, each containing two hypothetical COVID-19 vaccination scenario choices and a "do not vaccinate" choice. Half of the choice sets had a "Health Code" attribute that associated the "do not vaccinate" choice with a yellow Health Code implying restricted travel. Weighted, mixed effects multinomial logit regression was used to estimate preference utilities and predicted choice probabilities. RESULTS: Overall, 873 participants completed 4317 choice sets. Most participants attained at least college-level education (90.9%). 29.8% of participants were identified as vaccine hesitators (defined as being unsure or unwilling to receive a COVID-19 vaccination). With and without the "Health Code"-based vaccine mandate, there was an 8.6% (85% CI: 6.4% - 10.92%) and 17.3% (85% CI:13.1% - 21.6%) respective predicted probability that vaccine hesitators would choose "do not vaccinate" over a common vaccination scenario currently in China (i.e., free, domestic vaccine, 80% effectiveness, 10% probability of fever side-effects, administered in a large hospital, two doses). Corresponding predicted probabilities for people who did not express vaccine hesitancy was 0.3% (93% CI: 0.0% - 14.3%) and 3.5% (93% CI:2.3% - 4.8%). The "Health Code"-based mandate significantly increased willingness to vaccinate when vaccine efficacy was greater than 60%. CONCLUSION: Among vaccine hesitators with higher educational attainment, willingness to vaccinate for COVID-19 appears to increase if mobile technology-based vaccine mandates prohibit unvaccinated individuals from public spaces and public transportation. However, such mandates may not increase willingness if perceived vaccine efficacy is low.

Association between Adult Vaccine Hesitancy and Parental Acceptance of Childhood COVID-19 Vaccines: A Web-Based Survey in a Northwestern Region in China.

China has initiated the COVID-19 vaccination for children aged 15-17 years since late July 2020. This study aimed to determine the association between adult vaccine hesitancy and parental acceptance of childhood COVID-19 vaccines in a multi-ethnicity area of northwestern China. A web-based investigation was performed with a convenience sampling strategy to recruit the parents aged 20-49 years. In a total of 13,451 valid respondents, 66.1% had received the COVID-19 vaccination, 26.6% were intent to receive, while 7.3% were not intent, with an increasing vaccine hesitancy (p < 0.001). Moreover, vaccination uptake of four common vaccines in their children remained low (29.0% for influenza vaccine, 17.9% for pneumonia vaccine, 10.9% for rotavirus vaccine, 8.0% for Enterovirus-71 vaccine), while overall parental acceptance of childhood COVID-19 vaccines was 50.0% (32.7% for those aged 0-5, 46.6% for 6-10, 73.3% for 11-18; p < 0.001). Vaccination uptake of these four vaccines and parental acceptance of childhood COVID-19 vaccine were negatively associated with adult vaccine hesitancy. In addition, respondents mostly preferred childhood COVID-19 vaccines with weak mild common adverse events (ß = 1.993) and no severe adverse events (ß = 1.731), demonstrating a positive association with adult vaccine hesitancy. Thus, it warrants specific countermeasures to reduce adult vaccine hesitancy and improve strategies for childhood vaccination.

COVID-19 vaccine coverage, concerns, and preferences among Chinese ICU clinicians: a nationwide online survey.

BACKGROUND: Clinicians in intensive care units (ICUs) have been prioritized for COVID-19 vaccination. We aim to understand the reasons behind vaccination refusal, and assess preferences for COVID-19 vaccines among Chinese ICU clinicians. RESEARCH DESIGN AND METHODS: ICU clinicians throughout China's mainland were contacted to participate in an online survey. We compared concerns with vaccination status, and through a discrete choice experiment (DCE) assessed preferences for vaccines in terms of effectiveness, risk of adverse reactions, duration of immunity, and whether coworkers have been vaccinated. RESULTS: Among 11,951 ICU respondents from 252 prefecture-level regions, vaccination coverage was 75.4%, with an additional 9.2% not vaccinated but intending to, and 16.1% not vaccinated and not intending to. ICU clinicians not intending to be vaccinated significantly expressed more concerns about the speed of vaccine development (30.1%) and adverse reactions (65.9%). In the DCE, the only significant difference in preferences of a COVID-19 vaccine was for safety, with those not intending to have a stronger preference for a vaccine with fewer adverse reactions (OR = 4.49), compared to those already vaccinated (OR = 2.90) or those intending to vaccinate (OR = 3.46). CONCLUSION: Increasing vaccination coverage among Chinese ICU clinicians will require strong norms surrounding vaccination and transparency about safety information.

Epidemiological and co-infection characteristics of common human coronaviruses in Shanghai, 2015-2020: a retrospective observational study.

The coronavirus disease (COVID-19) pandemic is a major challenge worldwide. However, the epidemic potential of common human coronaviruses (HCoVs) remains unclear. This study aimed to determine the epidemiological and co-infection characteristics of common HCoVs in individuals with influenza-like illness (ILI) and severe acute respiratory infection (SARI). This retrospective, observational, multicentre study used data collected from patients admitted to nine sentinel hospitals with ILI and SARI from January 2015 through December 2020 in Shanghai, China. We prospectively tested patients for a total of 22 respiratory pathogens using multi-real-time polymerase chain reaction. Of the 4541 patients tested, 40.37% (1833/4541) tested positive for respiratory pathogens and 3.59% (163/4541) tested positive for common HCoVs. HCoV infection was more common in the non-endemic season for respiratory pathogens (odds ratio: 2.33, 95% confidence interval: 1.64-3.31). HCoV-OC43 (41.72%, 68/163) was the most common type of HCoV detected. The co-infection rate was 31.29% (51/163) among 163 HCoV-positive cases, with HCoV-229E (53.13%, 17/32), the HCoV type that was most frequently associated with co-infection. Respiratory pathogens responsible for co-infections with HCoVs included parainfluenza virus, rhinovirus/enterovirus, influenza A virus, and adenovirus. Furthermore, we identified one patient co-infected with HCoV-OC43 and HCoV-NL63/HKU1. The prevalence of common HCoVs remains low in ILI/SARI cases, in Shanghai. However, the seasonal pattern of HCoVs may be opposite to that of other respiratory pathogens. Moreover, HCoVs are likely to co-exist with specific respiratory pathogens. The potential role of co-infections with HCoVs and other pathogenic microorganisms in infection and pathogenesis of ILI and SARI warrants further study.

Impact of a two-dose varicella immunization program on the incidence of varicella: a multi-year observational study in Shanghai, China.

BACKGROUND: It remains hesitant to include a two-dose varicella vaccine (VarV) in a national routine immunization program in China. We aimed to quantify the impact of the two-dose VarV on varicella incidence in Shanghai. RESEARCH DESIGN AND METHODS: We directly extracted the data of varicella cases and VarV doses in 2013-2020 in Shanghai, and then estimated the effects of two-dose VarV using a Serfling model. RESULTS: A two-dose VarV immunization program has been extensively implemented since October 2017 and become free since August 2018 in Shanghai. Before and after this program, varicella cases significantly declined in children (P < 0.01), whereas did not in adults aged >18 years (P = 0.22). Compared to the predicted number of varicella cases, actual number was significantly lower by 8% in 2018 and 28% in 2019. Among children aged 4-6 years, the reduction in varicella cases was largest. Moreover, there was a significant reduction in varicella cases throughout 2020 (P < 0.001), in which the decrease due to social distancing for the COVID-19 was 54%. CONCLUSIONS: A two-dose VarV immunization program may further reduce approximately one-third of varicella cases in Shanghai. Children <4 years and adults benefit less in this program, which warrants enhancing the immunization.

Vaccine Hesitancy and Rejection of a Vaccine for the Novel Coronavirus in the United States.

The arrival of the COVID-19 vaccine has been accompanied by increased discussion of vaccine hesitancy. However, it is unclear if there are shared patterns between general vaccine hesitancy and COVID-19 vaccine rejection, or if these are two different concepts. This study characterized rejection of a hypothetical COVID-19 vaccine, and compared patterns of association between general vaccine hesitancy and COVID-19 vaccine rejection. The survey was conducted online March 20-22, 2020. Participants answered questions on vaccine hesitancy and responded if they would accept the vaccine given different safety and effectiveness profiles. We assessed differences in COVID-19 rejection and general vaccine hesitancy through logistic regressions. Among 713 participants, 33.0% were vaccine hesitant, and 18.4% would reject a COVID-19 vaccine. Acceptance varied by effectiveness profile: 10.2% would reject a 95% effective COVID-19 vaccine, but 32.4% would reject a 50% effective vaccine. Those vaccine hesitant were significantly more likely to reject COVID-19 vaccination [odds ratio (OR): 5.56, 95% confidence interval (CI): 3.39, 9.11]. In multivariable logistic regression models, there were similar patterns for vaccine hesitancy and COVID-19 vaccine rejection by gender, race/ethnicity, family income, and political affiliation. But the direction of association flipped by urbanicity (P=0.0146, with rural dwellers less likely to be COVID-19 vaccine rejecters but more likely to be vaccine hesitant in general), and age (P=0.0037, with fewer pronounced differences across age for COVID-19 vaccine rejection, but a gradient of stronger vaccine hesitancy in general among younger ages). During the COVID-19 epidemic's early phase, patterns of vaccine hesitancy and COVID-19 vaccine rejection were relatively similar. A significant minority would reject a COVID-19 vaccine, especially one with less-than-ideal effectiveness. Preparations for introducing the COVID-19 vaccine should anticipate substantial hesitation and target concerns, especially among younger adults.

Sensitivity to COVID-19 Vaccine Effectiveness and Safety in Shanghai, China.

Several COVID-19 vaccines have been on the market since early 2021 and may vary in their effectiveness and safety. This study characterizes hesitancy about accepting COVID-19 vaccines among parents in Shanghai, China, and identifies how sensitive they are to changes in vaccine safety and effectiveness profiles. Schools in each township of Minhang District, Shanghai, were sampled, and parents in the WeChat group of each school were asked to participate in this cross-sectional Internet-based survey. Parents responded to questions about hesitancy and were given information about five different COVID-19 vaccine candidates, the effectiveness of which varied between 50 and 95% and which had a risk of fever as a side effect between 5 and 20%. Overall, 3673 parents responded to the survey. Almost 90% would accept a vaccine for themselves (89.7%), for their child (87.5%) or for an elderly parent (88.5%) with the most ideal attributes (95% effectiveness with 5% risk of fever). But with the least ideal attributes (50% effectiveness and a 20% risk of fever) these numbers dropped to 33.5%, 31.3%, and 31.8%, respectively. Vaccine hesitancy, age at first child's birth, and relative income were all significantly related to sensitivity to vaccine safety and effectiveness. Parents showed a substantial shift in attitudes towards a vaccine based on its safety and effectiveness profile. These findings indicate that COVID-19 vaccine acceptance may be heavily influenced by how effective the vaccine actually is and could be impeded or enhanced based on vaccines already on the market.

Modification of a vaccine hesitancy scale for use in adult vaccinations in the United States and China.

Most research on vaccine hesitancy has focused on parental attitudes toward childhood vaccination, but it will be important to understand dimensions of vaccine hesitancy in the adult population as more adult vaccines are introduced in the future. We modified the Vaccine Hesitancy Scale to target adult vaccines and provide measures of its reliability and validity relative to influenza vaccine uptake and COVID-19 vaccination acceptance in cross-sectional internet surveys in the United States and in China. We assessed the impact of vaccine hesitancy on influenza and COVID-19 vaccination using multivariable regression modeling, which informed concurrent validity of the adult Vaccine Hesitancy Scale (aVHS). Among 1103 participants in the March 2020 China survey, 5.4% would not accept a COVID-19 vaccine, whereas this figure was 18.8% for the March 2020 US survey and 27.3% for the June 2020 US survey. The aVHS exhibits good internal consistency in all three surveys. Models adjusted for age, gender and income level show that prevalence of COVID-19 vaccine acceptance was a fraction as high in those who scored higher on the VHS than those who scored lower on all three surveys. Prevalence of past and future flu vaccine acceptance was a fraction as high in those with higher aVHS scores than those with lower scores. Prevalence of COVID-19 vaccine acceptance is lower in those with higher vaccine hesitancy scores, which supports the scale's concurrent validity. The aVHS exhibits good internal consistency, making it a valid and reliable tool for measuring vaccination uptake.

Cross-Sectional Seroepidemiologic Study of Coronavirus Disease 2019 (COVID-19) among Close Contacts, Children, and Migrant Workers in Shanghai.

(1) Background: Along with an increasing risk caused by migrant workers returning to the urban areas for the resumption of work and production and growing epidemiological evidence of possible transmission during the incubation period, a study of Coronavirus Disease 2019 (COVID-19) is warranted among key populations to determine the serum antibody against the SARS-CoV-2 and the carrying status of SARS-CoV-2 to identify potential asymptomatic infection and to explore the risk factors. (2) Method: This is a cross-sectional seroepidemiologic study. Three categories of targeted populations (close contacts, migrant workers who return to urban areas for work, and school children) will be included in this study as they are important for case identification in communities. A multi-stage sampling method will be employed to acquire an adequate sample size. Assessments that include questionnaires and blood, nasopharyngeal specimens, and feces collection will be performed via home-visit survey. (3) Ethics and Dissemination: The study was approved by the Institute Review Board of School of Public Health, Fudan University (IRB#2020-04-0818). Before data collection, written informed consent will be obtained from all participants. The manuscripts from this work will be submitted for publication in quality peer-reviewed journals and presented at national or international conferences.

Social distancing in response to the novel coronavirus (COVID-19) in the United States.

In order to reduce the spread of SARS-CoV-2, much of the US was placed under social distancing guidelines during March 2020. We characterized risk perceptions and adherence to social distancing recommendations in March 2020 among US adults aged 18+ in an online survey with age and gender quotas to match the general US population (N = 713). We used multivariable logistic and linear regression to estimate associations between age (by generational cohort) and these outcomes. The median perceived risk of infection with COVID-19 within the next month was 32%, and 65% of individuals were practicing more social distancing than before the outbreak. Baby Boomers had lower perceived risk than Millennials (-10.6%, 95% CI: -16.2%, -5.0%), yet were more frequently social distancing (OR = 1.64; 95% CI: 1.05, 2.56). Public health outreach should focus on raising compliance with social distancing recommendations, especially among high risk groups. Efforts to address risk perceptions alone may be inadequate.

Clusters of 2019 coronavirus disease (COVID-19) cases in Chinese tour groups.

International travel may facilitate the spread of the novel coronavirus disease (COVID-19). The study describes clusters of COVID-19 cases within Chinese tour groups travelling in Europe January 16-28. We compared characteristics of cases and non-cases to determine transmission dynamics. The index case travelled from Wuhan, China, to Europe on 16 January 2020, and to Shanghai, China, on 27 January 2020, within a tour group (group A). Tour groups with the same outbound flight (group B) or the same tourism venue (group D) and all Chinese passengers on the inbound flight (group C) were investigated. The outbreak involved 11 confirmed cases, 10 suspected cases and six tourists who remained healthy. Group A, involving seven confirmed cases and six suspected cases, consisted of familial transmission followed by propagative transmission. There was less pathogenicity with propagative transmission than with familial transmission. Disease was transmitted in shared outbound flights, shopping venues within Europe and inbound flight back to China. The novel coronavirus caused clustered cases of COVID-19 in tour groups. When tourism and travel opens up, governments will need to improve screening at airports and consider increased surveillance of tour groups-particularly those with older tour members.

Pre-symptomatic transmission of novel coronavirus in community settings.

We used contact tracing to document how COVID-19 was transmitted across 5 generations involving 10 cases, starting with an individual who became ill on January 27. We calculated the incubation period of the cases as the interval between infection and development of symptoms. The median incubation period was 6.0 days (interquartile range, 3.5-9.5 days). The last two generations were infected in public places, 3 and 4 days prior to the onset of illness in their infectors. Both had certain underlying conditions and comorbidity. Further identification of how individuals transmit prior to being symptomatic will have important consequences.