Differences in incidence and fatality of COVID-19 by SARS-CoV-2 Omicron variant versus Delta variant in relation to vaccine coverage: A world-wide review.

We aim to evaluate the evolution differences in the incidence and case fatality rate (CFR) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta and Omicron variants. The average incidence and CFRs were described between different countries. A gamma generalized linear mixed model (GLMM) was used to compare the CFRs of Delta and Omicron variants based on vaccination coverage. Totally, 50 countries were included for analyses. The incidence of coronavirus disease 2019 (COVID-19) ranged from 0.16/100,000 to 82.95/100,000 during the Delta period and 0.03/100,000 to 440.88/100,000 during the Omicron period. The median CFRs were 8.56 (interquartile range [IQR]: 4.76-18.39) during the Delta period and 3.04 (IQR: 1.87-7.48) during the Omicron period, respectively. A total of 47 out of 50 countries showed decreased CFRs of the Omicron variant with the rate ratio ranging from 0.02 (95% confidence interval [CI]: 0.01-0.03) (in Cambodia) to 0.97 (95% CI: 0.87-1.08) (in Ireland). Gamma GLMM analysis showed that the decreased CFR was largely a result of the decreased pathogenicity of Omicron besides the increased vaccination coverage. The Omicron variant shows a higher incidence but a lower CFR around the world as a whole, which is mainly a result of the decreased pathogenicity by SARS-CoV-2's mutation, while the vaccination against SARS-CoV-2 still acts as a valuable measure in preventing people from death.

Molecular Epidemiology of Herpangina Children in Tongzhou District, Beijing, China, During 2019-2020.

Background: The changing pattern of pathogen spectrum causing herpangina in the time of coronavirus disease 2019 (COVID-19) pandemic was unknown. The purpose of this study was to investigate the changes on the molecular epidemiology of herpangina children during 2019-2020 in Tongzhou district, Beijing, China. Method: From January 2019 to December 2020, children diagnosed with herpangina were recruited by the staff from Tongzhou Center for Disease Control and Prevention (CDC) in Beijing. Viral RNA extraction from pharyngeal swabs was used for enterovirus (EV) detection and the complete VP1 gene was sequenced. The phylogenetic analysis was performed based on all VP1 sequences for EV genotypes. Result: A total of 1,331 herpangina children were identified during 2019-2020 with 1,121 in 2019 and 210 in 2020, respectively. The predominant epidemic peak of herpangina children was in summer and autumn of 2019, but not observed in 2020. Compared to the number of herpangina children reported in 2019, it decreased sharply in 2020. Among 129 samples tested in 2019, 61 (47.3%) children were detected with EV, while 22.5% (20/89) were positive in 2020. The positive rate for EV increased since June 2019, peaked at August 2019, and decreased continuously until February 2020. No cases were observed from February to July in 2020, and the positive rate of EV rebounded to previous level since August 2020. Four genotypes, including coxsackievirus A6 (CV-A6, 9.3%), CV-A4 (7.8%), CV-A10 (2.3%) and CV-A16 (10.1%), were identified in 2019, and only three genotypes, including CV-A6 (9.0%), CV-A10 (6.7%) and CV-A16 (1.1%), were identified in 2020. The phylogenetic analysis showed that all CV-A6 strains from Tongzhou located in Group C, and the predominant strains mainly located in C2-C4 subgroups during 2016-2018 and changed into C1 subgroup during 2018-2020. CV-A16 strains mainly located in Group B, which consisting of strains widely distributed around the world. Conclusions: The predominant genotypes gradually shifted from CV-A16, CV-A4 and CV-A6 in 2019 to CV-A6 in 2020 under COVID-19 pandemic. Genotype-based surveillance will provide robust evidence and facilitate the development of public health measures.

Change in willingness to COVID-19 vaccination in China: Two online surveys during the pandemic.

OBJECTIVE: As the variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to emerge, periodic vaccine booster immunization may become a normal policy. This study investigated the changes and factors associated with vaccination intentions in various epidemic situations, which can provide suggestions for the construction and modification of routine vaccination program strategies. METHODS: Two cross-sectional online surveys were conducted in January and June of 2021. The willingness and confidence of the coronavirus disease 2019 (COVID-19) vaccination were measured following propensity score matching (PSM) treatment. The difference in the willingness for COVID-19 Vaccination in the two surveys was analyzed by single or multi-factor analyses. RESULTS: The willingness to accept the SARS-CoV-2 vaccine was higher in the second survey than that in the first survey (90.5% vs. 66.6%, p < 0.001). Concerns about the vaccine's safety declined (71.0% vs. 47.6%, p < 0.001), but concerns about the efficacy increased (22.4% vs. 30.9%, p < 0.001). Confidence in the SARS-CoV-2 vaccine had an important impact on the increased uptake willingness (odds ratio = 3.19, 95% confidence interval: 2.23-4.58, p < 0.001). CONCLUSIONS: There has been a significant increase in attitudes towards the SARS-CoV-2 vaccine which was associated with higher vaccine confidence. Vaccine effectiveness received more concerns from respondents rather than safety after nearly 6 months' utilization of the SARS-CoV-2 vaccine. It indicates that aggressive communication and timely disclosure of vaccine data can build vaccine confidence.

Molecular Epidemiology of Herpangina Children in Tongzhou District, Beijing, China, During 2019-2020

Background The changing pattern of pathogen spectrum causing herpangina in the time of coronavirus disease 2019 (COVID-19) pandemic was unknown. The purpose of this study was to investigate the changes on the molecular epidemiology of herpangina children during 2019-2020 in Tongzhou district, Beijing, China. Method From January 2019 to December 2020, children diagnosed with herpangina were recruited by the staff from Tongzhou Center for Disease Control and Prevention (CDC) in Beijing. Viral RNA extraction from pharyngeal swabs was used for enterovirus (EV) detection and the complete VP1 gene was sequenced. The phylogenetic analysis was performed based on all VP1 sequences for EV genotypes. Result A total of 1,331 herpangina children were identified during 2019-2020 with 1,121 in 2019 and 210 in 2020, respectively. The predominant epidemic peak of herpangina children was in summer and autumn of 2019, but not observed in 2020. Compared to the number of herpangina children reported in 2019, it decreased sharply in 2020. Among 129 samples tested in 2019, 61 (47.3%) children were detected with EV, while 22.5% (20/89) were positive in 2020. The positive rate for EV increased since June 2019, peaked at August 2019, and decreased continuously until February 2020. No cases were observed from February to July in 2020, and the positive rate of EV rebounded to previous level since August 2020. Four genotypes, including coxsackievirus A6 (CV-A6, 9.3%), CV-A4 (7.8%), CV-A10 (2.3%) and CV-A16 (10.1%), were identified in 2019, and only three genotypes, including CV-A6 (9.0%), CV-A10 (6.7%) and CV-A16 (1.1%), were identified in 2020. The phylogenetic analysis showed that all CV-A6 strains from Tongzhou located in Group C, and the predominant strains mainly located in C2-C4 subgroups during 2016-2018 and changed into C1 subgroup during 2018-2020. CV-A16 strains mainly located in Group B, which consisting of strains widely distributed around the world. Conclusions The predominant genotypes gradually shifted from CV-A16, CV-A4 and CV-A6 in 2019 to CV-A6 in 2020 under COVID-19 pandemic. Genotype-based surveillance will provide robust evidence and facilitate the development of public health measures.

Willingness and SARS-CoV-2 Vaccination Coverage among Healthcare Workers in China: A Nationwide Study.

Background: The SARS-CoV-2 vaccine has been widely rolled out globally in the general populations. However, specific data on vaccination confidence, willingness or coverage among health care workers (HCWs) has been less reported. Methods: A cross-sectional online survey was conducted to specify the basic data and patterns of vaccination confidence, willingness and coverage among HCWs nationwide. Results: In total, 2386 out of 2583 (92.4%) participants were enrolled for analysis, and the rates of confidence in vaccine, professional institutes and government were 75.1%, 85.2% and 85.4%, respectively. The overall vaccination coverage rate was 63.6% which was adjusted as 82.8% for participants under current medical conditions or having contraindications. Confidence in vaccine safety was shown to be the most related factor to willingness among doctors, nurses, medical technicians and hospital administrators, while confidence in vaccine effectiveness as well as trust in government played the key role in formulating public health employees' willingness. 130 (7.1% of 1833) participants reporting willingness still not been vaccinated regardless of contraindications. Multivariate analysis among willingness participants showed that males, aged over 30 years, public health employees and higher vaccination confidence had significantly higher vaccination rates with ORs (95% confidence intervals) as 1.64 (1.08-2.49), 3.14 (2.14-4.62), 2.43 (1.46-4.04) or 2.31 (1.24-4.33). Conclusions: HCWs' confidence, willingness and coverage rates to the vaccine were generally at high levels. Heterogeneity among HCWs should be considered for future vaccination promotion strategies. The population's confidence in vaccination is not only the determinant to their willingness, but also guarantees their actual vaccine uptake.

All five COVID-19 outbreaks during epidemic period of 2020/2021 in China were instigated by asymptomatic or pre-symptomatic individuals.

INTRODUCTION: The significance of asymptomatic or pre-asymptomatic individuals in driving the COVID-19 epidemic in China or other countries remains uncertain. METHOD: We collected and analyzed all the epidemiologic and virological diagnostic details of the infected individuals released by public health authorities and reiterated every episode of outbreak on a timeline. All individuals associated with the five outbreaks had tested positive for SARS-CoV-2 infection. RESULTS: In this study, all five COVID-19 outbreaks reported in China since October 2020 were analyzed. The Kashgar outbreak in Xinjiang province came into light for the first time on October 22, 2020. However, it was initiated before October 11, 2020, by a local asymptomatic import and export worker, who was infected at the working place. Subsequently, his wife caught the infection, which led to 430 more infections reported in the outbreak. The Beijing outbreak with 41 cases was noticed for the first time on December 22, 2020. However, our analysis revealed that it was initiated by an asymptomatic individual from Indonesia on December 10, 2020. The Shenyang outbreak, with 38 cases, noticed for the first time on December 23, 2020, was initiated by a pre-symptomatic individual from South Korea on December 13, 2020. CONCLUSION: The asymptomatic or pre-symptomatic individuals during the asymptomatic period were unsuspectingly infected by SARS-CoV-2, and unintentionally transmitted the virus to a large number of people. These findings suggest that early detection of asymptomatic or pre-symptomatic individuals is of critical importance in preventing future outbreaks or epidemics.

Survival potential and infectiousness of SARS-CoV-2 in environment

Coronavirus disease 2019 (COVID-19) spreads rapidly and widely in the world, which is mainly transmitted through respiratory droplets and contact with contaminated media. In this study, SARS-CoV-2 was found to have a similar stability to severe acute respiratory syndrome coronavirus (SARS-CoV) by analyzing its survival time on different subject surfaces and main influencing factors in related research. SARS-CoV-2 can survive for several days at various subject surfaces or media at room temperature (stainless steel: 2 days, plastic: 3 days, glass: 4 days, etc.), and SARS-CoV-2 can persist for longer time at low temperature and low relative humidity, which has caused severe threat to public health and has posed severe challenges to the prevention and control of COVID-19. According to available data, SARS-CoV-2 has the characteristics of high infectiousness and high covertness, similar to influenza A virus. By understanding the survival potential and infectiousness of SARS-CoV-2 in environment, targeted disinfection and effective protection can be implemented to reduce the incidence of COVID-19.

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

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