Coverage and effectiveness of COVID-19 vaccines among people aged 60 years and above in Changning District of Shanghai / 上海预防医学

ObjectiveTo assess the coverage and effectiveness of COVID-19 vaccines in the elderly. MethodsThis study was conducted in Changning District of Shanghai， targeting people aged 60 years and above. Vaccination data between 21 December 2020 and 28 February 2022 was retrieved from the Shanghai Collective Immunization System. Information on confirmed cases of COVID-19 from March 2022 through May 2022 was collected from the National Notifiable Diseases Reporting System. Vaccine effectiveness was calculated using the screening method. ResultsAs of 28 February 2022， 69.89% of people aged ≥60 years had received ≥1-dose vaccine， 63.80% had received full primary vaccination and 31.91% had received a booster dose. Vaccination coverage declined over age， with the lowest coverage in the elderly aged ≥80 years. Moreover， COVID-19 vaccination provided the highest protection against severe/critical illness and death due to the Omicron variants in the elderly aged ≥60 years. Full primary vaccination showed 96.15%（95%CI：84.15‒99.06）of vaccine effectiveness and booster vaccination showed 100% of the effectiveness against severe/critical COVID-19 and death. ConclusionsFull primary and booster vaccination coverage in the elderly is low， especially in those aged 80 and above. Our study finds high protection against COVID-19 associated severe/critical illness and death from both full primary and booster vaccination of inactivated COVID-19 vaccines in the elderly aged ≥60 years.

Progress Update on the Epidemiology of COVID-19 Variants and the Assessment Status of Developed Vaccines

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has spread rapidly and diffused to more than 180 countries at varying severities. This pandemic has accounted for increased mortality and morbidity in developed as well as developing nations. The WHO has announced that there is a persistent need for the evaluation of the COVID-19 vaccine effectiveness (VE) against major outcomes, which include severe diseases, symptomatic COVID-19, and mortalities related to COVID-19. Therefore, mass vaccination programs using vaccines of high effectiveness are among the strategies that have been used by governments worldwide to impede the COVID-19 pandemic transmission. In this regard, massive efforts were made by governments, scientists, biomedical researchers, and healthcare professionals leading to the successful development of various vaccines to bring this pandemic under control. This editorial aims to shed light on the epidemiological status of COVID-19 variants, namely, Delta, Omicron, and Deltacron variants as well as discuss the effectiveness of the currently available COVID-19 vaccines.

Development of the India COVID-19 vaccine tracker

COVID-19 was declared a pandemic by the World Health Organization (WHO) on March 11, 2020. Since then, efforts were initiated to develop safe and effective vaccines. Till date, 11 vaccines have been included in the WHO’s emergency use list. The emergence and spread of variant strains of SARS-CoV-2 has altered the disease transmission dynamics, thus creating a need for continuously monitoring the real-world effectiveness of various vaccines and assessing their overall impact on disease control. To achieve this goal, the Indian Council of Medical Research (ICMR) along with the Ministry of Health and Family Welfare, Government of India, took the lead to develop the India COVID-19 Vaccination Tracker by synergizing three different public health databases: National COVID-19 testing database, CoWIN vaccination database and the COVID-19 India portal. A Vaccine Data Analytics Committee (VDAC) was constituted to advise on various modalities of the proposed tracker. The VDAC reviewed the data related to COVID-19 testing, vaccination and patient outcomes available in the three databases and selected relevant data points for inclusion in the tracker, following which databases were integrated, using common identifiers, wherever feasible. Multiple data filters were applied to retrieve information of all individuals ?18 yr who died after the acquisition of COVID-19 infection with or without vaccination, irrespective of the time between vaccination and test positivity. Vaccine effectiveness (VE) against the reduction of mortality and hospitalizations was initially assessed. As compared to the hospitalization data, mortality reporting was found to be much better in terms of correctness and completeness. Therefore, hospitalization data were not considered for analysis and presentation in the vaccine tracker. The vaccine tracker thus depicts VE against mortality, calculated by a cohort approach using person-time analysis. Incidence of COVID-19 deaths among one- and two-dose vaccine recipients was compared with that among unvaccinated groups, to estimate the rate ratios (RRs). VE was estimated as 96.6 and 97.5 per cent, with one and two doses of the vaccines, respectively, during the period of reporting. The India COVID-19 Vaccination Tracker was officially launched on September 9, 2021. The high VE against mortality, as demonstrated by the tracker, has helped aid in allaying vaccine hesitancy, augmenting and maintaining the momentum of India’s COVID-19 vaccination drive

COVID-19 post-vaccination in healthcare workers and vaccine effectiveness, Brazil, 2021

Abstract Objects: This study aimed to describe COVID-19 cases in healthcare workers at a large tertiary hospital, after a vaccination campaign, to understand the individual characteristics, timeliness, symptomatology, and severity of the conditions. Methods: The COVID-19 reporting files from the hospital's healthcare workers and their records in the vaccine registry were analyzed, regarding vaccination status, symptoms, sociodemographic characteristics, comorbidities, and outcomes. Vaccination descriptive analysis was carried out and the impact and effectiveness of vaccination in relation to symptomatic infection and hospitalization were estimated. Results: In a total of 696 PCR-confirmed COVID-19 patients, vaccination coverage for the 1st and 2nd dose was 92.8% and 85.5%. Patients with complete doses had a mean interval of 96.8 days between vaccination and the onset of symptoms. Of the 664 participants with available clinical data, 165 had at least 1 comorbidity. During the study, 12 patients were hospitalized, 58.3% with a complete vaccination schedule. Three of this group died. The effectiveness of vaccination for symptomatic cases and hospitalization was 22.1% and 69.0%, respectively. The impact of vaccination on symptomatic cases and hospitalization was 81.4% and 89.7%, respectively. Discussion: The majority of COVID-19 cases in the study were classified as mild. The impact of vaccination for confirmed cases was significant, both in reducing the incidence of symptomatic cases and hospitalizations. The presence of comorbidities in approximately » of the patients increased the risk of these individuals. The mean time interval between diagnosis and the 2nd dose of vaccine was longer in the hospitalized group, reinforcing the protective decline over longer periods.

A matched case-control study on protective effect of two doses of varicella vaccine in high-risk population / 中华微生物学和免疫学杂志

Objective:To investigate the protective effect of two doses of varicella vaccine in a population at high risk for varicella.Methods:The case group involved all varicella cases in classes with no less than three patients during varicella outbreaks in Tianjin schools from 2017 to 2019. A case-control study was carried out in a 1∶3 ratio. According to the seat position of each case, three nearby students who did not suffer from varicella were selected as controls. The protective effect of two doses of varicella vaccine was evaluated.Results:The total protective effect of varicella vaccine was 46.0% (95% CI: 42.7%-49.0%). The protective effect was 44.7% (95% CI: 41.2%-48.0%) for one-dose varicella vaccine and 80.0% (95% CI: 63.1%-89.2%) for two-dose varicella vaccine. For two doses of varicella vaccine, the protective effect was 87.6% (95% CI: 52.0%-96.8%) after 0-2 years and 76.6% (95% CI: 33.6%-91.5%) after 3-5 years.Conclusions:The protective effect of two doses of varicella vaccine is better than that of one dose. However, both one-dose and two-dose vaccines show decreased protective effect over time. A booster immunization could be considered in high-risk population with longer intervals since the last vaccination.

Meta-analysis on effectiveness of live attenuated influenza vaccine against seasonal influenza in children / 中华流行病学杂志

Objective@#To evaluate the effectiveness of live attenuated influenza vaccine (LAIV) in the prevention of seasonal influenza in children aged 2-17 years.@*Methods@#Literature retrieval of case-control studies on the effectiveness of LAIV against seasonal influenza in children published from January 2003 to November 2018 was conducted through Web of Science, PubMed, and ScienceDirect databases. The Stata 13.1 software was used for Meta-analysis.@*Results@#A total of 14 studies were included in this study, and all were test-negative design (TND) studies. Our Meta-analysis showed that the effectiveness of LAIV in children was 49% (95%CI: 40%-57%). Subgroup analysis found that the protection rate of LAIV was 35% against influenza A (H1N1) pdm09 (95%CI: 5%-56%), 35% against influenza A (H3N2) (95%CI: 21%-46%), and 71% against influenza B (95%CI: 55%-82%). The protection rates of trivalent LAIV and quadrivalent LAIV in children were 56% (95%CI: 48%-63%) and 44% (95%CI: 27%-57%), respectively. The protection rates of LAIV in Europe and North America were 65% (95%CI: 47%-77%) and 46% (95%CI: 36%-55%), respectively.@*Conclusion@#LAIV has a certain preventive effect on seasonal influenza in children aged 2-17 years.

Influenza Vaccine Effectiveness among Elementary School Students in Korea during the 2016-2017 Seasons: a Cross-Sectional Survey

Meta-analysis on effectiveness of live attenuated influenza vaccine against seasonal influenza in children / 中华流行病学杂志

To evaluate the effectiveness of live attenuated influenza vaccine (LAIV) in the prevention of seasonal influenza in children aged 2-17 years. Literature retrieval of case-control studies on the effectiveness of LAIV against seasonal influenza in children published from January 2003 to November 2018 was conducted through Web of Science, PubMed, and ScienceDirect databases. The Stata 13.1 software was used for Meta-analysis. A total of 14 studies were included in this study, and all were test-negative design (TND) studies. Our Meta-analysis showed that the effectiveness of LAIV in children was 49 (95: 40-57). Subgroup analysis found that the protection rate of LAIV was 35 against influenza A (H1N1) pdm09 (95: 5-56), 35 against influenza A (H3N2) (95: 21-46), and 71 against influenza B (95: 55-82). The protection rates of trivalent LAIV and quadrivalent LAIV in children were 56 (95: 48-63) and 44 (95: 27-57), respectively. The protection rates of LAIV in Europe and North America were 65 (95: 47-77) and 46 (95: 36-55), respectively. LAIV has a certain preventive effect on seasonal influenza in children aged 2-17 years.

Evaluation of the influenza vaccine effectiveness among children aged 6 to 72 months based on the test-negative case control study design / 中华预防医学杂志

Objective@#To assess the effectiveness of seasonal influenza vaccine among children aged 6 to 72 months.@*Methods@#The test-negative case control study was conducted based on available surveillance data which was from China Influenza Surveillance Information system (CSIS). From October 2016 to April 2017 and from October 2017 to April 2018,1 161 cases aged 6-72 months with influenza-like illness in Yongkang and Yiwu city, were selected as the study subjects, and the cases with influenza test-positive were selected as the case group (403 cases). Test-negative subjects were selected as control group (758 cases). The etiology and immunization data of the subjects were obtained from CSIS and Immune Information and Management System (IIMS) respectively. Vaccine effectiveness was estimated using multivariate logistic regression model,and the mixed effects of non-randomized control in TNCC study were equalized by using the propensity score (PS) method in the statistical analysis.@*Results@#The age of the subjects was (2.44±1.60) years,and there were 681 boys (58.66%). The age of case group was (2.62±1.58) years, and there were 246 boys (61.04%). The case group was including of 237 cases (58.81%) of influenza A (H3N2), 92 cases (22.83%) of influenza A (H1N1) pmd09, 62 cases (15.38%) of influenza B(Victoria) lineage, 11 cases (2.73%) of influenza B (Yamagata) lineage and one case (0.25%) co-infection of influenza [A(H3N2)+B (Victoria)]. The mean age of the control group was (2.35±1.61) years,and there were 435 boys (57.39%). Overall vaccine effectiveness (VE) against all type influenza for two seasons combined was 58% (95%CI: 31%-74%). An analysis by age groups showed 68% (95%CI:41%-82%) of the VE estimate among children aged 36-72 months while it was 28%(95%CI:-80%-71%)of the VE estimate among children aged 6-35 months. The VE estimate value was 54% (95%CI:16%-75%) against all type influenza and 65% (95%CI:24%-83%) against influenza A (H3N2) during the 2016-2017 season. During the 2017-2018 season, the VE estimate value was 69% (95%CI:18%-88%) against all type influenza.@*Conclusion@#Influenza vaccine is effective in preventing influenza virus infection during the flu season,especially the effect among children aged 36-72 months is higher compared to that among children aged 6-35 months.

Study on epidemic factors of varicella outbreak under high varicella vaccine coverage / 中华疾病控制杂志

Objective To explore the epidemic factors of varicella transmission under high varicella vacince coverage, assess the vaccine effectineness of one dose of varicella vaccine, so as to provide scientific basis for controlling the varicella outbreak and optimizing the varicella immunization strategy. Methods A 1 ∶〗2 paired case-control study of a varicella outbreak was conducted in a primary school in central region of Jiangsu Province in 2018. Analysis of varicella epidemic factors was performed using conditional logistic stepwise regression. Results This outbreak lasted for 14 days. A total of 45 students were infected with varicella, of which 71.1% were breakthrough cases. The fever, rash degree and disease course of breakthrough cases were all relatively mild compared with those without immune history (all P5 years and the initial immunization age <15 months were potential risk factors for breakthrough cases. The overall vaccine effectiveness of one dose of varicella vaccine was 77.9%(95% CI: 53.3%-92.1%). The fever, severity of the rash and the course of the disease were all milder than those without the history of immunization (all P<0.05). Conclusions The clinical symptoms of the breakthrough cases are relatively mild, and one dose of varicella vaccine is insufficient to control the outbreak of varicella with limited vaccine effectiveness. Two doses of varicella immunization strategy is recommended.

Association of the time that elapsed from last vaccination with protective effectiveness against foot-and-mouth disease in small ruminants

Routine and emergency vaccination of small ruminants against foot-and-mouth disease (FMD) is mandatory in many endemic countries, yet data on the field effectiveness of the vaccines used is scarce. We conducted an investigation of a serotype O FMD outbreak that took place in a sheep and goat pen, and estimated the effectiveness of various routine vaccination statuses. We also evaluated the protection provided by colostrum administration and emergency vaccination. Animals which were routinely vaccinated twice were not clinically affected while disease incidence was observed among animals routinely vaccinated only once (p = 0.004 according to a two-sided Fisher's exact test). In groups vaccinated only once, there was a significant association between the average time that elapsed since last vaccination and the disease incidence (n = 5; Spearman correlation coefficient: r(s) = 1.0, p < 0.01). In addition, non-vaccinated lambs fed colostrum from dams vaccinated more than 2 months before parturition had a mortality rate of 33%. Administration of emergency vaccination 2 days after the occurrence of the index case was the probable reason for the rapid blocking of the FMD spread within 6 days from its onset in the pen.

Efectividad de la vacuna antimeningocócica VA-MENGOC-BC® en el primer año de vida, Cuba, 1997-2008 / Effectiveness of the anti-meningococcal vaccine VA-MENGO-BC® in the first year of life of Cuban children, 1997-2008

Introducción: la enfermedad meningocócica constituye un importante problema de salud mundial. Desde 1991 la vacuna VA-MENGOC-BC® se aplica en Cuba a los niños menores de 1 año. Objetivo: evaluar la efectividad de la vacuna VA-MENGOC-BC®. Métodos: para la evaluación poslicenciamiento de VA-MENGOC-BC® se estudiaron los lactantes con enfermedad meningocócica notificados entre 1997 y 2008. Resultados: ocurrieron 114 casos para una incidencia media anual de 7,1/100 000 lactantes. La estimación de la efectividad vacunal media resultó de 84,0 por ciento, oscilando entre 68 y 104 por ciento. La ocurrencia de enfermedad meningocócica en los no vacunados fue de 20,2 por ciento (23/114); 79,8 por ciento (91/114) en lactantes con edad de vacunación y en 75,8 por ciento (69/91) se precisó la fecha de inmunización. Tenían una sola dosis de vacuna aplicada 26,4 por ciento (24/91) y 73,6 por ciento (67/91) recibió el esquema completo (2 dosis). La enfermedad meningocócica predominó en los primeros 6 meses de edad, declinó a partir de este momento y comenzó de nuevo su ascenso a los 10 y 11 meses. Predominó la forma meníngea (89,5 por ciento); la letalidad general fue de 7 por ciento (8/114), con 4,4 por ciento para la meningococemia y 2,6 por ciento para la meningitis. Conclusiones: la efectividad de VA-MENGOC-BC® fue satisfactoria. Se sugiere realizar un análisis por un grupo de expertos sobre la necesidad de aplicar una tercera dosis.

Introduction: meningococcal disease is an important health problem worldwide. Since 1991 the vaccine VA-MENGOC-BC has been used in Cuban under one-year old infants. Objective: to evaluate the effectiveness of the vaccine VA-MENGO-BC®. Methods: for the evaluation after licensing this vaccine, all the infants affected by meningococcal disease between 1997 and 2008 were studied. Results: a total number of 114 cases were recorded. The annual average incidence was 7.1 per 100 000 infants. The mean vaccinal effectiveness for the period was 84.0 percent, ranging from 68 percent to 104 percent. The frequency of disease in unvaccinated children was 20.2 percent (23/114); 79.8 percent (91/114) within the vaccination age, but only 75.8 percent (69/91) of them had confirmed the immunization date. Only 26.4 percent (24/91) had one single dose applied whereas 73.6 percent (67/91) had completed their vaccination schedule (2 doses). The meningococcal disease prevailed in the first six months of life, declined afterwards and then started to rise again at 10 and 11 months of age. The meningeal form of clinical presentation predominated (89.5 percent); case-fatality rate was 7.0 percent (8/114), being 4,4 percent for meningococcemia and 2,6 percent for meningitis. Conclusions: the vaccine VA-MENGOC-BC® effectiveness in infants was satisfactory. It is suggested that further analysis be made by a group of experts on the use of a booster dose.

Meta analysis on the effectiveness of inactivated influenza vaccine / 中华流行病学杂志

Objective To understand the effectiveness of inactivated influenza vaccines (IIV).Methods We did a Meta analysis on IIV effectiveness with papers published during March 1998 and May 2008 in Chinese journals, using fixed model or random model according to the heterogeneity of the studies. Results A total number of 13 studies were included, of which 11 were cohort studies and 2 were randomized controlled trials. Through Meta analysis on cohort studies regarding the effectiveness against influenza like illness (ILI) ,we noticed that the effectiveness of the vaccine was 66% (95%CI:51%-76 % ) in children and adolescents, but 47 % (25 %-63 % ) in adults, and 53 % (20%-72%) in the elderly. Conclusion IIV was effective in protecting against influenza like illness.

Using Stochastic Simulation Model Vaccine Effectiveness / 대한의료정보학회지

Several measures for vaccine effectiveness have been proposed which go beyond the direct effectiveness measurement which measures the benefit of vaccination to the recipient. In this study, a Micropopulation, Monte-Carlo model of nursing home outbreaks was used to evaluate the different vaccine measures. Simulation sets at five different vaccination levels: 0%. :5%. 50%, 75% and 100% vaccinated were run. Each simulation set was a 1000 outbreaks at a medium influenza level of .08 and an underlying vaccine efficacy of .5. The indirect measures show clearly how the population benefits as the percentage of vaccination increases. The average vaccine effectiveness measure, which compares the vaccinated attack rate with what would have been expected had no vaccine been given, showed a vaccine effectiveness of .540 at 25% vaccination; .759 at 50% vaccination: .866 at 75% vaccination; and .925 at 100% vaccination. These experiments show the usefu1ness of simulation models in presenting interrelated complex information in an understandable format.