Project description:We studied the immunogenicity of the Oxford-AstraZeneca vaccine in health-care workers of a major infectious diseases hospital in Vietnam. We measured neutralizing antibodies before and 14 days after each dose, and at day 28 and month 3 after dose 1. A total of 554 workers (136 men and 418 women; age range, 22-71 years; median age, 36 years) participated with the study. Of the 144 participants selected for follow-up after dose 1, 104 and 94 gave blood for antibody measurement at weeks 6 and 8, and at month 3 after dose 1, respectively. The window time between the two doses was 6 weeks. At baseline, none had detectable neutralizing antibodies. After dose 1, the proportion of participants with detectable neutralizing antibodies increased from 27.3% (151 of 554) at day 14 to 78.0% (432 of 554) at day 28. Age correlated negatively with the development and the levels of neutralizing antibodies. However, at day 28, these differences were less profound, and women had a greater seroconversion rate and greater levels of neutralizing antibodies than men. After dose 2, these age and gender associations were not observable. In addition, the proportion of study participants with detectable neutralizing antibodies increased from 70.2% (73 of 104) before dose 2 (week 6, after dose 1) to 98.1% (102 of 104) 14 days later. At month 3, neutralizing antibodies decreased and 94.7% (89 of 94) of the study participants remained seropositive. The Oxford-AstraZeneca COVID-19 vaccine is immunogenic in Vietnamese health-care workers. These data are critical to informing the deployment of the COVID-19 vaccine in Vietnam and in Southeast Asia, where vaccination coverage remains inadequate.
Project description:IntroductionEthiopia is the second most populous country in Africa. Ethiopia received most of its COVID-19 vaccines through donations. The Oxford AstraZeneca vaccine is the first to be donated to Ethiopia by the COVAX facility. Healthcare workers were the priority population that received the Oxford AstraZeneca COVID-19 vaccine. However, there was no nationwide study on the safety of the vaccine in Ethiopia. This study aimed to measure the prevalence and predictors of self-reported side effects of the Oxford AstraZeneca vaccine.Materials and methodsThe study employed a cross-sectional design. A sample of healthcare workers who took Oxford AstraZeneca COVID-19 vaccine was drawn from four regions of Ethiopia; namely, Amhara, Oromia, Somali, and Southwest. Data were collected on sociodemographic characteristics, medical anamnesis, COVID-19 related anamnesis, and COVID-19 vaccine anamnesis via telephone interview. Descriptive and inferential analyses were done. The software, IBM SPSS Statistics v21.0, was used for analyses of data.ResultsOut of 384 people, 346 responded (response rate: 90.1%). Female accounted for 34.1% of the respondents. The mean age of the respondents was 31.0 years (Standard Deviation (SD) = 7.4). Nurses accounted for 43.7% of the respondents. The prevalence of at least one local- and systemic-side effect was 50.6 and 44.5%, respectively. The most frequent local- and systemic- side effect were injection site pain and headache, respectively. Both types of side effects mostly subsided in the first 3 days. A third of healthcare workers with side effects took at least one medication. Paracetamol followed by diclofenac sodium were taken by healthcare workers to overcome side effects. There was no independent predictor of local side effect. After controlling for age and chronic diseases, the odds of healthcare workers with COVID-19 like symptoms to experience systemic side effects was 1.38 (Confidence Interval (CI): 1.04-1.82) times more than that of healthcare workers without COVID-19 like symptoms.ConclusionsThe prevalence of local- and systemic-side effects of the Oxford AstraZeneca COVID-19 vaccine was modest. As the symptoms were mostly common in the first 3 days, it is preferable to monitor healthcare workers at least in the first 3 days following the administration of the vaccine.
Project description:This report describes the clinical context and autopsy findings in the first reported fatal case of acute disseminated encephalomyelitis (ADEM), developed after being vaccinated using the Oxford/AstraZeneca COVID-19 vaccine. ADEM is a rare autoimmune disease, causing demyelination in the brain and spinal cord. A wide variety of precipitating factors can trigger ADEM, and it has long been known to be a rare adverse event following some types of vaccinations. Recently, ADEM has also been associated with COVID-19 infection and (very rarely) with COVID-19 vaccination. The reports of the latter however all pertain to living patients. Our case demonstrates that ADEM should be considered in patients developing neurological symptoms post COVID-19 vaccination, although that this adverse reaction is likely to remain extremely rare. Our report further emphasizes the added value of comprehensive post mortem investigation to confirm ante mortem diagnosis and to determine vaccination safety.
Project description:Background COVID-19 vaccines approved in the UK are highly effective in general population cohorts, however, data on effectiveness amongst individuals with clinical conditions that place them at increased risk of severe disease are limited. Methods We used GP electronic health record data, sentinel virology swabbing and antibody testing within a cohort of 712 general practices across England to estimate vaccine antibody response and vaccine effectiveness against medically attended COVID-19 amongst individuals in clinical risk groups using cohort and test-negative case control designs. Findings There was no reduction in S-antibody positivity in most clinical risk groups, however reduced S-antibody positivity and response was significant in the immunosuppressed group. Reduced vaccine effectiveness against clinical disease was also noted in the immunosuppressed group; after a second dose, effectiveness was moderate (Pfizer: 59.6%, 95%CI 18.0-80.1%; AstraZeneca 60.0%, 95%CI -63.6-90.2%). Interpretation In most clinical risk groups, immune response to primary vaccination was maintained and high levels of vaccine effectiveness were seen. Reduced antibody response and vaccine effectiveness were seen after 1 dose of vaccine amongst a broad immunosuppressed group, and second dose vaccine effectiveness was moderate. These findings support maximising coverage in immunosuppressed individuals and the policy of prioritisation of this group for third doses.
Project description:BackgroundSeveral countries paused their rollouts of the Oxford-AstraZeneca coronavirus disease-19 (COVID-19) vaccine in mid-March 2021 due to concerns about vaccine-induced thrombosis and thrombocytopenia. Many warned that this risked damaging public confidence during a critical period of pandemic response. This study investigated whether the pause in the use of the Oxford-AstraZeneca vaccine had an impact on subsequent vaccine uptake in European countries.MethodsWe used a difference-in-differences approach capitalizing on the fact that some countries halted their rollouts whilst others did not. A longitudinal panel was constructed for European Economic Area countries spanning 15 weeks in early 2021. Media reports were used to identify countries that paused the Oxford-AstraZeneca vaccine and the timing of this. Data on vaccine uptake were available through the European Centre for Disease Control and Prevention COVID-19 Vaccine Tracker. Difference-in-differences linear regression models controlled for key confounders that could influence vaccine uptake, and country and week fixed effects. Further models and robustness checks were performed.ResultsThe panel included 28 countries, with 19 in the intervention group and 9 in the control group. Pausing the Oxford-AstraZeneca vaccine was associated with a 0.52% decrease in uptake for the first dose of a COVID-19 vaccine and a 1.49% decrease in the uptake for both doses, comparing countries that paused to those that did not. These estimates are not statistically significant (P = 0.86 and 0.39, respectively). For the Oxford-AstraZeneca vaccine only, the pause was associated with a 0.56% increase in uptake for the first dose and a 0.07% decrease in uptake for both doses. These estimates are also not statistically significant (P = 0.56 and 0.51, respectively). All our findings are robust to sensitivity analyses.ConclusionsAs new COVID-19 vaccines emerge, regulators should be cautious to deviate from usual protocols if further investigation on clinical or epidemiological grounds is warranted.
Project description:ObjectiveThe pandemic of coronavirus disease 2019 (COVID-19) is a major threat to community health, and vaccinations are a safe and effective way to reduce disease loads around the world. This study aimed to assess the age and gender disparity in adverse effects following the first dose of the AstraZeneca COVID-19 vaccine among the vaccinated population in Eastern Ethiopia.MethodsA community-based cross-sectional study design was conducted among 832 randomly selected individuals from December 1st to 20th, 2021, in eastern Ethiopia. Data were collected by face-to-face interviews using a pretested structured questionnaire. Data were analyzed using the SPSS V26. Descriptive summary statistics were done. A chi-square test statistic was computed to assess the difference in adverse effects between age groups and both genders.ResultOut of 832 study participants who had taken the first dose of AstraZeneca vaccine, 96.3% of them felt at least one adverse effect. The magnitude of adverse reactions was higher among male participants. The reported adverse reactions were significantly higher in the age group of 50-60 years with comorbidity than those of <50 and >60 years of age.ConclusionOverall, there is a significant age and gender difference in adverse effects following the first dose of the AstraZeneca COVID-19 vaccine. In addition, adverse reactions were higher among people with comorbidity in the age group of 50-60 years. The Harari Regional Health Bureau should provide training for frontline healthcare workers on early recognition and response to adverse effects of the COVID-19 vaccine. In addition, information and education should be provided to the community as a whole regarding recognition and the appropriate measures to be taken.
Project description:Aim To determine the effects of knowledge, attitudes, and perceptions of primary care health workers toward receiving the Oxford AstraZeneca vaccine in North Central, Trinidad. Methods A pretested de novo questionnaire containing forty-eight (48) closed ended questions and one (1) open ended question was used to gather data. Descriptive and inferential statistics were used to analyze the data obtained from the questionnaire. These included percentages, means and standard deviations for the descriptive aspect and the Chi-Square test to examine any significant associations. Analysis of Variance (ANOVA) was used to assess any significant differences in means among several categories and the independent samples t-test for assessing any significant difference in means between two categories. Results 273 respondents completed the questionnaire. Most of the participants (72.2%) were female and within the age range 25–36 (56.0%). The mean knowledge score about the AstraZeneca vaccine was 16.28 (SD = 2.28) out of 19 with an overall correct response rate of 79%. 30.4% of participants had a good attitude score and 59.7% had a positive perception toward the AstraZeneca vaccine. There were significant associations between knowledge and marital status (p = 0.001), income level (p = 0.001), education level (p < 0.001), and length of employment (p = 0.041); attitudes and sex (p = 0.01), age (p = 0.04), marital status (p = 0.009), income level (p < 0.001), education level (p = 0.005) and category of staff (p < 0.001); perception and sex (p = 0.002), marital status (p = 0.027), income level (p < 0.001), and category of staff (p < 0.001). Conclusions The main contributors to vaccine hesitancy were inadequate duration of clinical trials and fear of adverse side effects. A significant number of participants (17%) were unwilling to get the vaccine due to lack of information.