ABSTRACT
After about a year and a half (at the moment these lines are being written) since the start of the massive vaccination campaign in which, thanks to the high coverage achieved in all groups eligible for vaccination, it has been possible to significantly reduce the morbidity and mortality due to COVID-19, it is important to review the scientific basics that have supported the recommendations implemented to date and those that could be adopted in the near future taking into consideration the epidemiological situation. The objective of this article is, therefore, to address the foundations of some of the technical decisions proposed by the Committee on Programme and Registry of Vaccinations (National Immunization Technical Advisory Group in Spain) and the Technical Working Group on Vaccination against COVID-19. Throughout the eleven updates of the Vaccination Strategy against COVID-19 in Spain, several issues pose intense debate as the vaccination intervals between doses, the convenience of using different types of vaccines, the use of heterologous schemes of vaccination, the benefits of hybrid immunity and the use of a fourth dose (second booster dose) for selected populations. All this without forgetting essential aspects of safety of vaccines. This article is divided into the following sections: Vaccination intervals;Heterologous or mixed scheme;Hybrid immunity (vaccination after infection and infection after vaccination [breakthrough]);Second booster dose.
ABSTRACT
Vaccinating children against Covid raised a debate, due to generally mild clinical presentation. The decision to vaccinate teenagers was motivated by the global public health need: to decrease transmission to other age groups. Among adolescents, the efficacy (better immunity than in young adults) and safety of vaccines was clearly demonstrated. Among 5-to-12-year-olds, due to lower contamination the collective benefit is less clear, and when the m-RNA vaccines were available for this age group, the Omicron variant was predominant and their effect on non-severe infections and transmission had yet to be determined. Individual benefit is based both on somatic criteria and on the child's schooling and mental health. Children under 5 years of age received a 3 micro g dose of vaccine, which is one tenth of the adult dose, resulting in immunogenicity similar to that of 16-to-25-year-olds.
ABSTRACT
Objective To analyze IgG test results of serum SARS-CoV-2 antibody in people after booster vaccinations against SARS-CoV-2, and to provide a basis for the booster vaccination. Methods There were 314 healthy individuals who had been vaccinated with the COVID-19 vaccine. Depending on their inoculation situation, they were divided into three groups:the booster injection group(1 week to 2 months after booster vaccination)of 205 cases, <180 days after two doses group(<180 days after two doses of COVID-19 vaccine)of 49 cases, and >180 days after two doses group(>180 days after two doses of COVID-19 vaccine)of 60 cases. The positive rate of IgG in serum of the three groups was measured using the colloidal gold method. Results The serum COVID-19 antibody IgG positive rates were 83.9% in the booster injection group, 18.4% in the <180 days after two doses group, and 5.0% in the >180 days after two doses group, with statistically significant difference between any two groups(all P < 0.05). In the booster injection group, the serum COVID-19 antibody IgG positive rate was 85.2% in people who received a booster injection more than a month, while those who received a booster injection less than a month had a positive rate of 75.9%, and there was no significant difference between these two groups(P > 0.05). In the booster injection group, the positive rates of serum COVID-19 antibody IgG were 85.1% in males and 82.4% in females, with no significant difference(P > 0.05). In the booster injection group, people at the age of 18 and 50 had a positive serum COVID-19 antibody IgG rate of 86.0%, while those over 50 had a positive rate of 58.3%, and there was significant difference between them(P < 0.05). Conclusions Compared with two injections of the COVID-19 vaccine, the booster injection can significantly increase the positive rate of the antibody IgG of COVID-19, which results in a stronger immune response. There is a lower IgG positive rate of COVID-19 antibodies in those aged over 50 years following the booster dose of COVID-19 vaccine than in those aged 18- 50 years.
ABSTRACT
Objective: To analyze the nucleic acid shedding time of Omicron variant of novel coronavirus in the elderly patients with non-severe infection, and to explore the related factors affecting the nucleic acid shedding time. Methods: A total of 104 elderly patients with non-severe COVID-19 were divided into early negative group (<10 days) and late negative group ( 10 d) by the nucleic acid shedding time. The population information, vaccination, previous diseases, blood biochemical and inflammatory indicators, nucleic acid ORFIab gene and N gene Ct values were collected and compared between the two groups. The Spearman rank correlation and multiple linear regression were conducted to explore the influencing factors of the nucleic acid shedding time. Results: The mean time of nucleic acid shedding of Omicron variant in the early negative group was 7.26: 1.54 d, compared with 12.96: 2.44 d in the late negative group. There were significant differences in age, the ratio of chronic heart failure, chronic pulmonary disease and booster vaccination for COVID-19 and the first nucleic acid Ct value between the two groups (P < 0.05). Spearman correlation analysis showed that the nucleic acid shedding time of Omicron was positively correlated with age, chronic heart failure and serum level of procalcitonin, but negatively correlated with the vaccination booster and the first tested nucleic acid Ct value. Multiple linear regression analysis showed that age, vaccination booster and the first tested nucleic acid Ct value were the independent influencing factors of the nucleic acid shedding time. Conclusions: Age, vaccination booster for COVID-19 and the first tested nucleic acid Ct value were the independent influencing factors of nucleic acid shedding in [the elderly non-severe patients infected by SARS-CoV-2 Omicron. Vaccination booster for COVID-19 in the elderly vulnerable groups can shorten the time of nucleic acid shedding.
ABSTRACT
Purpose: Although the fast development of safe and effective messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 has been a success, waning humoral immunity has led to the recommendation of booster immunization. However, knowledge of the humoral immune response to different booster strategies and the association with adverse reactions is limited. Materials and Methods: We investigated adverse reactions and anti-spike protein immunoglobulin G (IgG) concentrations among health care workers who received primary immunization with mRNA-1273 and booster immunization with mRNA-1273 or BNT162b2. Results: Adverse reactions were reported by 85.1% after the first dose, 94.7% after the second dose, 87.5% after a third dose of BNT162b2, and 86.0% after a third dose of mRNA-1273. They lasted for a median of 1.8, 2.0, 2.5, and 1.8 days, respectively; 6.4%, 43.6%, and 21.0% of the participants were unable to work after the first, second, and third vaccination, respectively, which should be considered when scheduling vaccinations among essential workers. Booster immunization induced a 13.75-fold (interquartile range, 9.30-24.47) increase of anti-spike protein IgG concentrations with significantly higher concentrations after homologous compared to heterologous vaccination. We found an association between fever, chills, and arthralgia after the second vaccination and anti-spike protein IgG concentrations indicating a linkage between adverse reactions, inflammation, and humoral immune response. Conclusion: Further investigations should focus on the possible advantages of homologous and heterologous booster vaccinations and their capability of stimulating memory B-cells. Additionally, understanding inflammatory processes induced by mRNA vaccines might help to improve reactogenicity while maintaining immunogenicity and efficacy.
ABSTRACT
The World Health Organization (WHO) recommended coronavirus disease 2019 (COVID-19) booster dose vaccination after completing the primary vaccination series for individuals ≥18 years and most-at-risk populations. This study aimed to estimate the pooled proportion of COVID-19 vaccine booster dose uptake and intention to get the booster dose among general populations and healthcare workers (HCWs). We searched PsycINFO, Scopus, EBSCO, MEDLINE Central/PubMed, ProQuest, SciELO, SAGE, Web of Science, Google Scholar, and ScienceDirect according to PRISMA guidelines. From a total of 1079 screened records, 50 studies were extracted. Meta-analysis was conducted using 48 high-quality studies according to the Newcastle-Ottawa Scale quality assessment tool. Using the 48 included studies, the pooled proportion of COVID-19 vaccine booster dose acceptance among 198,831 subjects was 81% (95% confidence interval (CI): 75-85%, I2 = 100%). The actual uptake of the booster dose in eight studies involving 12,995 subjects was 31% (95% CI: 19-46%, I2 = 100%), while the intention to have the booster dose of the vaccine was 79% (95% CI: 72-85%, I2 = 100%). The acceptance of the booster dose of COVID-19 vaccines among HCWs was 66% (95% CI: 58-74%), I2 = 99%). Meta-regression revealed that previous COVID-19 infection was associated with a lower intention to have the booster dose. Conversely, previous COVID-19 infection was associated with a significantly higher level of booster dose actual uptake. The pooled booster dose acceptance in the WHO region of the Americas, which did not include any actual vaccination, was 77% (95% CI: 66-85%, I2 = 100%). The pooled acceptance of the booster dose in the Western Pacific was 89% (95% CI: 84-92%, I2 = 100), followed by the European region: 86% (95% CI: 81-90%, I2 = 99%), the Eastern Mediterranean region: 59% (95% CI: 46-71%, I2 = 99%), and the Southeast Asian region: 52% (95% CI: 43-61%, I2 = 95). Having chronic disease and trust in the vaccine effectiveness were the significant predictors of booster dose COVID-19 vaccine acceptance. The global acceptance rate of COVID-19 booster vaccine is high, but the rates vary by region. To achieve herd immunity for the disease, a high level of vaccination acceptance is required. Intensive vaccination campaigns and programs are still needed around the world to raise public awareness regarding the importance of accepting COVID-19 vaccines needed for proper control of the pandemic.
ABSTRACT
The emergence of SARS-CoV-2 variants of concern (VOCs), especially the sweeping spread of the delta variant, and differing public health management strategies, have rendered global eradication of SARS-CoV-2 unlikely. The currently available COVID-19 vaccines, including the inactivated whole virus vaccines, mRNA vaccines, and adenovirus-vectored vaccines, are effective in protecting people from severe disease and death from COVID-19, but they may not confer good mucosal immunity to prevent the establishment of infection and subsequent viral shedding and transmission. Mucosal vaccines delivered via intranasal route may provide a promising direction, which, if given as a third dose after a two-dose series of intramuscular vaccination, likely promotes mucosal immunity in addition to boosting the systemic cell-mediated immunity and antibody response. However, immunity induced by vaccination, and natural infection as well, is likely to wane followed by re-infection as in the case of human coronaviruses OC43, 229E, NL63, and HKU1. It is a challenge to prevent and control COVID-19 worldwide with the increasing number of VOCs associated with increased transmissibility and changing antigenicity. Nevertheless, we may seek to end the current pandemic situation through mass vaccination and gradual relaxation of non-pharmaceutical measures, which would limit the incidence of severe COVID-19. Repeated doses of booster vaccine will likely be required, similar to influenza virus, especially for the elderly and the immunocompromised patients who are most vulnerable to infection.
ABSTRACT
The fourth booster vaccination was approved in Israel during Omicron (B.1.1.529) variant surge due to increasing SARS-CoV2 breakthrough infections among recently vacci-nated, reasons for this resurgence is not clear. In this Observational study, we analyzed verified SARS-CoV2 infections among over 60 years of age based on vaccination schedule (December 20, 2020-January 29, 2022);infec-tions, severe illness and deaths based on vac-cine immunity (between August 1, 2021-Janu-ary 29, 2022) using Israel COVID-19 dashboard data. There were a total of 214,394 SARS-CoV2 infections (December 20, 2020-Janaury 29, 2022;based vaccination schedule), 165,899 infections;6,267 severe illnesses and 2,031 deaths (August 1, 2021-Janaury 29, 2022) an-alyzed based vaccine immunity among over 60 years old. Vaccination with two doses, main-tained vaccine effectiveness (VE) of 93.2% (95% CI 90-95.5%) for 16 weeks until May 8, 2021 with 14.2% breakthrough infections. When there were no public health restrictions (June-July 2021) partially vaccinated has significantly lower infection rates (X2 [2, N=721]=190.79,p<0.001) with VE of 80.4% (95% CI 69.1-98.3%), while in-fection rates among vaccinated with two doses and unvaccinated are not statistically significant and decline of VE to 6.4% (95% CI -9.9-19.3%) among vaccinated with two doses. After rein-statement of restrictions since July 29, 2021, the VE of vaccinated with two doses improved to 68.0% (95% CI 56.7-76.7%), the third booster showed significantly higher breakthrough infec-tions (26.4%) and a shorter period of 12 weeks effectiveness until October 23, 2021 and by No-vember 20, 2021 the infections rates of vacci-nated with third booster are not statistically bet-ter than partially vaccinated (X2 [1, N=54]=1,85, p=0.17). During the Omicron variant surge, the VE of third booster declined to 42.7% (95% CI 39.9-45.3%) and the infection rates were sig-nificantly higher than vaccinated with two doses (X2[1,N=5898]=8.50, p=0.003) as of January 15, 2022 and subsequently showed improvement in VE to 51.7% (95% CI 50.2-53.2%) and signifi-cantly lower infection rates than vaccinated with two doses (X2[1,N=12380]=98.28, p=<0.001) by January 29, 2022. The vaccinated without valid-ity group (partially vaccinated;past 1-2 doses with expired Green Passes) showed significant-ly lower infection rates (X2 [1, N=15727]=295.3, p<0.001) during December 5,2021-January 29, 2022 period compared to vaccinated with validity (95% of them received third booster dose, and have Green Pass access) group that showed significantly increased infection rates and substantially increased percentages of se-vere illness and deaths.
ABSTRACT
BACKGROUND: The coronavirus disease 2019 (COVID-19) vaccine is not readily available in many countries where dosing interval is spaced more than ideal. Patients with chronic kidney disease, especially those on maintenance hemodialysis, have a tendency for a reduced immune response. This study was undertaken to demonstrate the distinct humoral immune response to the viral vector COVID-19 vaccine in patients with kidney failure receiving maintenance hemodialysis. METHODS: The study was carried out with two cohorts: 1) patients receiving maintenance hemodialysis and 2) healthcare workers from the same dialysis center as controls, each group with 72 subjects. Participants received a dose of Covishield ChAdOx1 nCoV-19 coronavirus vaccine. The humoral immunological response was determined using electrochemiluminescence immunoassay which quantitatively measures antibodies to the severe acute respiratory syndrome coronavirus 2 spike protein receptor-binding domain. RESULTS: All study subjects in the control group developed a humoral response (antibody titer of ≥0.8 U/mL), while only 64 of 72 in the dialysis group (88.9%) were responders. Age (ρ = -0.234, p = 0.04) and sodium level (ρ = 0.237, p = 0.04) correlated with low antibody titer in bivariate analysis. In multivariate analysis, only age (odds ratio, 1.10; 95% confidence interval, 1.01-1.22; p = 0.045) was associated with nonresponders. CONCLUSION: Our study demonstrated a weak antibody response of hemodialysis patients to the viral vector COVID-19 vaccine. Older age was associated with nonresponders. Evaluation of both humoral and cellular immunity after the second vaccine dose and serial antibody titers can help determine the need for booster shots.