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1.
Vaccines (Basel) ; 10(7)2022 Jun 21.
Article in English | MEDLINE | ID: covidwho-1964125

ABSTRACT

Objective: The COVID-19 pandemic is still continuing throughout the world, with newer genetic variants regularly appearing from different parts of the world. Considering the waning of immunity against COVID-19 infection even with two doses of the COVID-19 vaccine, regulatory authorities have authorised booster COVID-19 vaccination in many countries, especially for vulnerable populations, including healthcare workers. The current study analysed factors predicting the third (booster) dose of COVID-19 vaccine intention, including the health belief model (HBM), among the healthcare workers in Saudi Arabia. Methods: The current study was a cross-sectional online survey performed from 1st October 2021 to 30th November 2021, using a questionnaire prepared in GoogleTM form among healthcare workers in Saudi Arabia. The questionnaire asked demographic factors, COVID-19 experience of participants, subjective assessment of health, intention of COVID-19 booster dose vaccination, preferences for local/foreign-made vaccines, and health belief of the study population related to COVID-19 infection and COVID-19 booster dose. Results: This study received 2059 complete responses. The study population reported mixed health belief with respect to the susceptibility of COVID-19 infection, and higher health belief perception regarding the severity. The perceptions of the study participants regarding the benefits of COVID-19 booster dose were positive. There were few barriers to COVID-19 booster dose expressed by study participants. A total of 1464 (71.1%) study participants reported positive intent for receiving a COVID-19 booster dose. The study showed significant association between definite intention to receive a booster dose and nationality (p = 0.001), marital status (p = 0.017), gender (p < 0.001), education level (p = 0.001), monthly income (p < 0.001), and co-morbid medical illness (p = 0.045). The perception of the COVID-19 booster vaccine as a good idea to minimise worries about getting COVID-19 (OR = 2.28, CI 1.89-2.76), and perceptions that receiving the third (booster) dose reduces the risk of COVID-19 infection and associated complications (OR= 2.69, CI = 2.17-3.34), of the perceived benefit construct of HBM, predicted significantly higher definite intention to receive a booster dose. The concern with the safety of the vaccine (OR= 0.40, CI 0.34-0.47) under the perceived barriers construct of HBM predicted as significantly higher no definite intention to receive a booster dose. Conclusions: The results of the present study can guide policy makers in their efforts to promote booster doses of COVID-19 vaccination among the healthcare workers in Saudi Arabia.

2.
J Neurol ; 2022 Jul 26.
Article in English | MEDLINE | ID: covidwho-1958991

ABSTRACT

BACKGROUND: The assessment of the safety and the humoral response to a third booster dose of the BNT162b2 mRNA COVID-19 vaccine is relevant in patients with Multiple Sclerosis (pwMS) treated with Ocrelizumab (OCR) or Fingolimod (FNG). METHODS: Serum samples were collected from Healthy controls (HCs) and pwMS treated with OCR or FNG at the following time-points: before the first of two vaccine doses (T0); 8 (T1), 16 (T2), 24 (T3) weeks after the first dose; within 8 weeks before (T0b) and after (T1b) the booster dose. IgG antibodies to SARS-CoV-2 trimeric spike protein (Anti-TSP IgG) were quantified and expressed as binding antibody units (BAU)/mL. RESULTS: 40 HCs, 28 pwMS on OCR and 19 on FNG were included. At T0b 12 (42.9%) pwMS on OCR and 6 (31.6%) on FNG were still positive while, at T1b 16 (57.14%) pwMS on OCR and 16 (84.2%) on FNG, passed the threshold of positivity. The increase of Anti-TSP IgG levels at T1b was higher for: (i) HCs with respect to OCR (p < 0.001) and FNG (p = 0.032) groups; (ii) pwMS on FNG compared with pwMS on OCR (p < 0.001). No socio-demographic, clinical or laboratory variables were able to predict the anti-TSP IgG increase between T0b and T1b. Neither clinical relapses nor severe adverse events were reported in pwMS after each dose of vaccine. CONCLUSIONS: The third booster dose of BNT162b2 mRNA vaccine to OCR- and FNG-treated pwMS revives the humoral response, independently of any clinical variable, and manifests a good safety and tolerability profile.

3.
Hum Vaccin Immunother ; : 2099210, 2022 Jul 26.
Article in English | MEDLINE | ID: covidwho-1956541

ABSTRACT

This study was conducted to ascertain whether people in China would be willing to pay for an inactivated COVID-19 vaccine booster dose. An online survey estimating participants' willingness to pay (WTP) for a booster dose of COVID-19 vaccine was conducted in Taizhou, China. The participants received ane-mail or e-poster on WeChat. A total of 1576 subjects participated the survey. A total of 66.4% (1046/1576) of the respondents were willing to pay for a booster dose of COVID-19 vaccine for themselves. Using binary logistic regression analysis, the following factors were significantly related to a WTP for a booster dose of COVID-19 vaccine: 1) confidence in the safety of the COVID-19 vaccines (high vs. low, OR: 4.30, 95%CI: 1.61-11.43), 2) confidence in the preventive effectiveness of the COVID-19 vaccines against SARS-CoV-2 virus (moderate vs. little, OR: 1.76, 95%CI: 1.30-2.38; great vs. little, OR: 2.244, 95%CI: 1.62-3.12), and 3) COVID-19 vaccine hesitancy (unhesitant vs. very unhesitant, OR: 0.67, 95%CI: 0.45-1.02; hesitant vs. very unhesitant, OR: 0.29, 95%CI: 0.19-0.44; very hesitant vs. very unhesitant, OR: 0.09, 95%CI: 0.03-0.27). This study revealed that a moderate proportion of participants responded that they would be willing to pay for a booster dose of COVID-19 vaccine. These findings suggest the importance of a detailed assessment and a health education plan that better understands the population's risk perception as well as the potential health risks in China.

4.
Int J Biol Sci ; 18(12): 4629-4641, 2022.
Article in English | MEDLINE | ID: covidwho-1954696

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has undergone multiple mutations since its emergence, and its latest variant, Omicron (B.1.1.529), is the most contagious variant of concern (VOC) which poses a major and imminent threat to public health. Since firstly reported by World Health Organization (WHO) in November 2021, Omicron variant has been spreading rapidly and has become the dominant variant in many countries worldwide. Omicron is the most mutated variant so far, containing 60 mutations in its genome, including 37 mutations in the S-protein. Since all current COVID-19 vaccines in use were developed based on ancestral SARS-CoV-2 strains, whether they are protective against Omicron is a critical question which has been the center of study currently. In this article, we systemically reviewed the studies regarding the effectiveness of 2- or 3-dose vaccines delivered in either homologous or heterologous manner. The humoral and cellular immune responses elicited by various vaccine regimens to protect against Omicron variant are discussed. Current understanding of the molecular basis underlying immune escape of Omicron was also analyzed. These studies indicate that two doses of vaccination are insufficient to elicit neutralizing antibody responses against Omicron variant. Nevertheless, Omicron-specific humoral immune responses can be enhanced by booster dose of almost all type vaccines in certain degree, and heterologous vaccination strategy may represent a better choice than homogenous regimens. Intriguingly, results of studies indicate that all current vaccines are still able to elicit robust T cell response against Omicron. Future focus should be the development of Omicron variant vaccine, which may induce potent humoral as well as cellular immune responses simultaneously against all known variants of the SARS-CoV-2 virus.


Subject(s)
COVID-19 , Viral Vaccines , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Immunity, Cellular , SARS-CoV-2
5.
Vaccines (Basel) ; 10(6)2022 May 30.
Article in English | MEDLINE | ID: covidwho-1954115

ABSTRACT

The aim of our study was to assess the immunogenicity of the third dose of the BNT162b2 mRNA COVID-19 vaccine (Comirnaty) in a cohort of 129 health-care workers in Greece whose anti-S1 RBD IgG titers were monitored over the course of nine months. Titers were measured for each participant just before the third dose (nine months after the second dose) and also one month after the third dose. Of the 129 participants, 19 had been previously infected before starting the vaccination scheme. The SARS-CoV-2 IgG II Quant assay on the Architect System was employed to longitudinally assess the titers of IgG against the receptor-binding domain of the S1 subunit of the spike protein (anti-S1 RBD). Boosters raised Geometric Mean Concentrations (GMCs) by a factor of approximately 47 relative to levels at 9 months and by a factor of approximately 23 relative to levels at 6 months. The immune response one month after the third dose was significantly higher than the response achieved one month after the second dose (p = 0.008). In conclusion, our findings verify the potent immunogenicity elicited by the third dose in all age and prior COVID-19 status groups, suggesting that the timely administration of the third (booster) dose maximizes the immunogenic potential of the vaccine.

6.
Ann Med Surg (Lond) ; 79: 103941, 2022 Jul.
Article in English | MEDLINE | ID: covidwho-1936016

ABSTRACT

The COVID-19 pandemic since 2020 created havoc across the globe. This led to the establishment of effective vaccines to mitigate the virus. Several vaccines are developed to create immunity amongst the population. However, due to emerging variants of SARS-CoV-2, despite a double dose of vaccines, people have still infected that termed vaccine breakthrough infection. This paper aims to highlight the recent re-surging massive outbreak of COVID-19 in China despite mass vaccination and, discuss the issue of vaccine breakthrough infection, possible causes, and recommendations to enhance immunity and curb the transmission.

7.
Vaccines (Basel) ; 10(7)2022 Jul 18.
Article in English | MEDLINE | ID: covidwho-1939061

ABSTRACT

Coronavirus disease 2019 (COVID-19) continues to pose a threat to public health with the potential for the emergence of new variants. Vaccines are the milestones to control and slow down the damage of the pandemic. As of January 2021, a two-dose regimen with CoronaVac was authorized in Turkey. Due to the waning seroprevalence rate of SARS-CoV-2 over time, BNT162b2 or CoronaVac has been administered as the third dose following a two-dose CoronaVac regimen as a national vaccination policy. As of 14 January 2021, 5243 volunteers who received two doses of the CoronaVac vaccine at Hacettepe University Adult Vaccine Center were followed prospectively. In our study, relative vaccine effectiveness (VEff) for the third dose of the CoronaVac was 58.24% and 87.27% for BNT162b2 in preventing symptomatic COVID-19 cases. There were no hospitalizations, intensive care unit admissions, or deaths in third-dose booster groups with either BNT162b2 or CoronaVac, yielding 100% effectiveness. Both homologous or heterologous third-dose boosters provided further protection against severe COVID-19 and should be prioritized as an effective strategy to combat the COVID-19 pandemic.

8.
Vaccines (Basel) ; 10(7)2022 Jul 17.
Article in English | MEDLINE | ID: covidwho-1939058

ABSTRACT

Background. The recent spread of the highly mutated SARS-CoV-2 Omicron variant (B.1.1.529) has raised concerns about protection against COVID-19 in congregate settings such as prisons, characterized by a high risk of transmission and possible difficulties in obtaining adequate vaccination coverage. The present study aims to investigate the spread of an outbreak of COVID-19 in an Italian correctional facility during the dominant circulation of the Omicron BA.1 variant, and also considers BNT162b2 mRNA vaccination coverage among inmates. A COVID-19 screening campaign by RT-PCR was performed on 515 detainees from 4-30 January 2022, in response to an outbreak that began in the correctional facility. Furthermore, 101 serum samples collected from healthy inmates 21 days after having received the second dose of the BNT162b2 vaccine were tested for neutralizing antibodies against both the wild-type SARS-CoV-2 strain and the Omicron BA.1 variant. The global attack rate during the study period was 43.6% (RR 0.8), progressively reducing from unvaccinated inmates (62.7%, RR 1.8) to those who had one dose (52.3%, RR 1.5), two doses (full cycle) (45.0%, RR 1.3), and the third dose (booster) vaccinated group (31.4%, RR 0.7). The percentage of SARS-CoV-2 positive subjects among unvaccinated inmates was significantly higher than in the other groups (p < 0.001), while no significant difference was observed between inmates with one or two vaccine doses. Only two of the positive inmates were hospitalized for COVID-19. The geometric mean titer of neutralizing antibodies in the tested sub-group after two doses of vaccine was lower than in previous studies against the wild-type virus, and showed a complete lack of neutralization against the Omicron variant in 92.1% of individuals. The findings support the need to prioritize vaccination in correctional facilities, as a public health measure to increase the protection of inmates and consequently of prison workers and the community against COVID-19, in coordination with the other prevention strategies.

9.
Vaccines (Basel) ; 10(7)2022 Jul 12.
Article in English | MEDLINE | ID: covidwho-1939043

ABSTRACT

BACKGROUND: Given the prevalence of the omicron variant and decreased immunity provided by vaccines, it is imperative to enhance resistance to COVID-19 in the old population. We planned to explore the hesitancy rate toward the booster dose of the COVID-19 vaccine and the association between risk perception and the abovementioned rate among people aged 60 and older. METHODS: This national cross-sectional study was conducted in mainland China from 25 May to 8 June 2022, targeting people who were 60 years old or above. Four dimensions were extracted from the Health Belief Model (HBM) to assess participants' perceived risk levels, including perceived susceptibility, perceived severity, perceived barriers, and perceived benefit. An independent Chi-square test was used to compare the vaccine hesitancy rates among different groups stratified by characteristics. Univariable and multivariable logistic regression models were performed to explore the associations between risk perception and hesitancy rate. RESULTS: Of 3321 participants, 17.2% (95% CI: 15.9-18.5%) were hesitant about booster shots of COVID-19 vaccines. Believing that they were ineligible for vaccination due to certain illnesses (38.3%), concern about vaccine safety (32.0%), believing the booster shots were unnecessary (33.1%), and their limitation on movements (28.0%) were the main reasons for vaccine hesitation. Adjusted by all the selected covariates, people with low perception level of susceptibility (aOR = 1.39, 95% CI: 1.00-1.92) and benefit (low: aOR = 3.31, 95% CI: 2.01-5.45; moderate: aOR = 2.23, 95% CI: 1.75-2.85) were less likely to receiving the booster dose, and the same results were found in people with higher perceived barriers (moderate: aOR = 2.67, 95% CI: 2.13-3.35; high: aOR = 2.04, 95% CI: 1.14-3.67). Our estimates were stable in all four models. CONCLUSIONS: In total, 17.2% of the people aged 60 years and older in China were hesitant about booster dose of COVID-19 vaccines, and it was closely associated with a lower level of perceived susceptibility and benefit, as well as a higher level of perceived barriers. Concerns about contraindications, vaccine safety, and limited movements were the main reasons for vaccine hesitancy. Targeted public health measure is a priority to improve the understanding of the elderly on their own susceptibility and vulnerability and clear the obstacles to vaccination.

10.
Hum Vaccin Immunother ; : 2095162, 2022 Jul 20.
Article in English | MEDLINE | ID: covidwho-1937608

ABSTRACT

Scientists have emerged with innovative research on non-human primates showing that the booster dose of the COVID-19 vaccine increases neutralizing antibody levels against all variants. The current cross-sectional survey was designed to evaluate the knowledge, perception, and acceptance of the booster dose of the COVID-19 vaccine among the patients visiting the various dental clinics in Aseer region, Kingdom of Saudi Arabia. A total of 609 dental patients were selected from various dental clinics by a simple random probability sampling method. The questionnaire was designed in multiple languages and categorized as demographic information, knowledge, perception, and acceptance of participants to a booster dose. An anonymous, self-administered, closed-ended online, and paper-based questionnaire was used to assess the above parameters. In the current survey, the majority of the participants were Saudis (80.8%) with an age mean of 37.7 ± 8.7 years. About 68.6% (418 out of 609) of participants had poor knowledge about the booster dose. Significant differences in the levels of knowledge were found in relation to gender, area of residency, education, nationality, and occupation. The distribution of level of perception of booster dose differs significantly among participants of different marital statuses and nationalities. Hesitation to booster was reported more in the rural than in the urban population. Despite a low level of knowledge, a higher level of good perception and acceptance of booster doses were reported among the studied population.

11.
Vaccines (Basel) ; 10(7)2022 Jul 08.
Article in English | MEDLINE | ID: covidwho-1928700

ABSTRACT

Despite the BNT162b2 vaccination coverage, rapid transmission of Omicron SARS-CoV-2 has occurred, which is suspected to be due to the immune escape of the variant or waning vaccine efficacy of multiple BNT162b2 vaccination doses. Our study aims to compare immunogenicity against Omicron prior to and post a booster dose of BNT162b2 in healthy adolescents, and to evaluate their attitudes toward booster dose vaccination. A cross sectional study was conducted among healthy adolescents aged 12-17 who received two doses of BNT162b2 more than 5 months ago. Participants and their guardians performed self-reported questionnaires regarding reasons for receiving the booster. A 30 ug booster dose of BNT162b2 was offered. Immunogenicity was evaluated by a surrogate virus neutralization test (sVNT) against the Omicron variant, and anti-spike-receptor-binding-domain IgG (anti-S-RBD IgG) taken pre-booster and 14-days post-booster. From March to April 2022, 120 healthy Thai adolescents with a median age of 15 years (IQR 14-16) were enrolled. sVNT against Omicron pre- and post-booster had 11.9 (95%CI 0-23.9) and 94.3 (90.6-97.4) % inhibition. Geometric means (GMs) of anti-S-RBD IgG increased from 837 (728, 953) to 3041 (2893, 3229) BAU/mL. Major reasons to receive the booster vaccination were perceived as vaccine efficacy, reduced risk of spreading infection to family, and safe resumption of social activities. A booster dose of BNT162b2 elicits high immunogenicity against the Omicron variant. Motivation for receiving booster doses is to reduce risk of infection.

12.
Vaccines (Basel) ; 10(7)2022 Jul 08.
Article in English | MEDLINE | ID: covidwho-1928699

ABSTRACT

The emergence of breakthrough infections and new highly contagious variants of SARS-CoV-2 threaten the immunization in individuals who had completed the primary COVID-19 vaccination. This systematic review and meta-analysis investigated, for the first time, acceptance of the first COVID-19 booster dose and its associated factors among fully vaccinated individuals. We followed the PRISMA guidelines. We searched Scopus, Web of Science, Medline, PubMed, ProQuest, CINAHL and medrxiv from inception to 21 May 2022. We found 14 studies including 104,047 fully vaccinated individuals. The prevalence of individuals who intend to accept a booster was 79.0%, while the prevalence of unsure individuals was 12.6%, and the prevalence of individuals that intend to refuse a booster was 14.3%. The main predictors of willingness were older age, flu vaccination in the previous season, and confidence in COVID-19 vaccination. The most important reasons for decline were adverse reactions and discomfort experienced after previous COVID-19 vaccine doses and concerns for serious adverse reactions to COVID-19 booster doses. Considering the burden of COVID-19, a high acceptance rate of booster doses could be critical in controlling the pandemic. Our findings are innovative and could help policymakers to design and implement specific COVID-19 vaccination programs in order to decrease booster vaccine hesitancy.

13.
Hum Vaccin Immunother ; : 2094653, 2022 Jul 12.
Article in English | MEDLINE | ID: covidwho-1927247

ABSTRACT

In October 2021, the Italian Ministry of Health has planned the offer of a booster dose of anti-SARS-CoV-2 vaccine for healthcare workers (HCWs), recommending the simultaneous administration of the third anti-SARS-CoV-2 dose and the influenza vaccine. The immunogenicity and serological response of co-administration are questioned. This is a retrospective cohort pilot study. We evaluated in a sample of HCWs the serological response 1 month after the administration of the third dose, comparing it between subjects who chose for co-administration (Cominarty+Flucelvax) and subjects who preferred the administration of the anti-SARS-CoV-2 vaccine. The study population comprised 20 HCWs, 9 (45.0%) chose co-administration (Group 1), and 11 (55.0%) preferred the administration of the COVID-19 vaccine alone (Group 2). A statistical significant difference of the variation of IgG anti-spike-protein antibodies between the serological evaluation at 1 month after the third dose and the serological evaluation 1 month after the basal routine with Comirnaty between Group 1 (-4,842.9; 95%CI = -15,799.2-6,113.2) and Group 2 (9,258.9; 95%CI = 1,081.0-17,435.9; p-value = 0.029) was reported. New scientific evidences are necessary to clarify this critical issue to guarantee both the best immunogenicity of COVID-19 vaccination and an high vaccine coverage for influenza vaccination.

14.
J Biomed Sci ; 29(1): 49, 2022 Jul 07.
Article in English | MEDLINE | ID: covidwho-1923546

ABSTRACT

BACKGROUND: With the continuous emergence of new SARS-CoV-2 variants that feature increased transmission and immune escape, there is an urgent demand for a better vaccine design that will provide broader neutralizing efficacy. METHODS: We report an mRNA-based vaccine using an engineered "hybrid" receptor binding domain (RBD) that contains all 16 point-mutations shown in the currently prevailing Omicron and Delta variants. RESULTS: A booster dose of hybrid vaccine in mice previously immunized with wild-type RBD vaccine induced high titers of broadly neutralizing antibodies against all tested SARS-CoV-2 variants of concern (VOCs). In naïve mice, hybrid vaccine generated strong Omicron-specific neutralizing antibodies as well as low but significant titers against other VOCs. Hybrid vaccine also elicited CD8+/IFN-γ+ T cell responses against a conserved T cell epitope present in wild type and all VOCs. CONCLUSIONS: These results demonstrate that inclusion of different antigenic mutations from various SARS-CoV-2 variants is a feasible approach to develop cross-protective vaccines.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antibodies, Neutralizing , Antibodies, Viral , Broadly Neutralizing Antibodies , COVID-19/prevention & control , Humans , Mice , SARS-CoV-2/genetics , Vaccines, Synthetic , mRNA Vaccines
15.
Expert Rev Vaccines ; : 1-9, 2022 Jul 13.
Article in English | MEDLINE | ID: covidwho-1915425

ABSTRACT

INTRODUCTION: Immunogenicity after the CoronaVac vaccine remains uncertain, especially regarding infections with the coronavirus variants of concern and waning immunity. METHODS: This was a single-center, open-label clinical trial designed to assess the immunogenicity and safety of BBIBP-CorV, AZD1222, or BNT162b2 as the third vaccination. The key eligible criteria were individuals at least 18 years old who were fully vaccinated with two doses of CoronaVac vaccine for 2-4 months. The primary endpoint was the ratio of the geometric mean concentration (GMC) of the total anti-receptor binding domain (RBD) antibody post-vaccination compared with that pre-vaccination. The secondary endpoint was reactogenicity within 7 days. RESULTS: Forty-one participants received AZD1222, 40 received BBIBP-CorV, and 40 received BNT162b2. The GMC of anti-RBD antibody at 2 weeks post-vaccination was 31,138.67 binding antibody units (BAU)/mL for BNT162b2, 6,412.10 BAU/mL for AZD1222, and 1,092.7 BAU/mL for BBIBP-CorV. Compared with pre-vaccination, the ratio of anti-RBD concentration was 690.24 for BNT162b2, 130.02 for AZD1222, and 17.79 for BBIBP-CorV. No potentially life-threatening adverse reaction were observed within 7 days. CONCLUSION: A third vaccination with the heterologous vaccine, BBIBP-CorV, AZD1222, or BNT162b2, can elicit a robust immune response, without serious adverse events in participants fully vaccinated with the CoronaVac vaccine.

16.
J Clin Virol Plus ; 2(3): 100094, 2022 Aug.
Article in English | MEDLINE | ID: covidwho-1914576

ABSTRACT

Introduction: The necessity of a booster dose is a matter that has not been as yet illuminated, although it is noted that neutralizing antibody titers decrease over time. We aimed therefore to evaluate antibody titers and seroconversion rates after a booster mRNA vaccine and a booster inactivated vaccine. Methods: A total of 322 participants were divided into three main groups, with two subgroups each, based on their vaccinations and previous infection history. The levels of anti-SARS-CoV-2 Ig-G were analyzed with the Elecsys® Anti-SARS-CoV-2 S assay. Results: The antibody titers showed a linear and significant increase from one vaccine group to the other, displaying progressive changes from group 2IV to group 3IV, and then to group 2IV/mRNA. All of the seronegative participants were in the 2IV(-) subgroup; 93.3% of the participants whose antibody titers were above the upper limit were in the 2IV/mRNA group. Doctors were much more inclined to have a booster dose and mRNA vaccines than nurses. The status of being a doctor increases the rate of having a booster dose 7.8 times; likewise, each annual increase in age increases the rate 1.05 times. Conclusion: Anti-SARS-CoV-2 IgG levels decrease over time. The antibody response rate to only two doses of the inactivated vaccine was meager, so a booster dose is necessary to maintain the effectiveness of inactivated vaccines. The third dose of the vaccine, especially that of the mRNA vaccine, which was found to be much more superior to the inactivated vaccine, should be strongly recommended.

17.
Vaccines (Basel) ; 10(6)2022 May 25.
Article in English | MEDLINE | ID: covidwho-1911673

ABSTRACT

The Republic of Serbia applied the booster dose of the following COVID-19 vaccines: BNT162b2 mRNA (Pfizer-BioNTech), Sinopharm BBIBP-CorV (Vero Cell®), Gam-COVID-Vac (Sputnik V) and ChAdOk1 nCoV-19 (AstraZeneca). We aimed to examine the immunogenicity and reactogenicity of the booster dose and identify factors related to immune response and adverse events. Panel study, conducted during August and September 2021, included 300 persons receiving the booster dose at the Institute of Public Health of Serbia. Blood samples were taken on the day of receiving the booster dose, and after 7 and 28 days. When applying homologous regimen, the average increase in anti-spike immunoglobulin G was 8782.2 (after 7 days), 1213.9 after 28 days, while 9179.5 (after 7 days) and 16,728.1 after 28 days of heterologous regimen. Sinopharm BBIBP-CorV (p < 0.001) and Sputnik V (p < 0.001), age 65 and over (p = 0.001) and currently smoking (p < 0.001) were independently associated with lower levels of anti-spike immunoglobulin G. Female sex (OR = 1.77; 95%CI = 1.01-3.12), previous COVID-19 infection (OR = 3.62; 95%CI = 1.13-11.63) and adverse events after the second dose (OR = 2.66; 95%CI = 1.33-5.32) were independently associated with intense systemic adverse events 7 days after. Booster dose significantly increased antibodies titers, especially 28 days after heterologous regimen, without a significant increase in reactogenicity.

18.
Biomedicines ; 10(7)2022 Jun 28.
Article in English | MEDLINE | ID: covidwho-1911182

ABSTRACT

The continuous variability of SARS-CoV-2 and the rapid waning of specific antibodies threatens the efficacy of COVID-19 vaccines. We aimed to evaluate antibody kinetics one year after SARS-CoV-2 vaccination with an mRNA vaccine in healthcare workers (HCW), with or without a booster. A marked decline in anti-Spike(S)/Receptor Binding Domain (RBD) antibody levels was registered during the first eight months post-vaccination, followed by a transitory increase after the booster. At three months post-booster an increased antibody level was maintained only in HCW vaccinated after a prior infection, who also developed a higher and long-lasting level of anti-S IgA antibodies. Still, IgG anti-nucleocapsid (NCP) fades five months post-SARS-CoV-2 infection. Despite the decline in antibodies one-year post-vaccination, 68.2% of HCW preserved the neutralization capacity against the ancestral variant, with a decrease of only 17.08% in the neutralizing capacity against the Omicron variant. Nevertheless, breakthrough infections were present in 6.65% of all participants, without any correlation with the previous level of anti-S/RBD IgG. Protection against the ancestral and Omicron variants is maintained at least three months after a booster in HCW, possibly reflecting a continuous antigenic stimulation in the professional setting.

19.
Patient Prefer Adherence ; 16: 1525-1537, 2022.
Article in English | MEDLINE | ID: covidwho-1910799

ABSTRACT

Purpose: COVID-19 vaccines are critical for containing the pandemic and preventing serious SARS-CoV-2 infections. In addition to the two main doses, a booster dose has been utilized to improve immunity. The aim of current study is to evaluate Iraqi adult population knowledge, attitudes, and practices towards COVID-19 booster dose. Subjects and Methods: This online cross-sectional survey of adult Iraqis (n = 754) assessed the attitudes of people who have had both immunizations regarding a potential COVID-19 vaccine booster dosage and to identify potential factors that might impact these attitudes. Factors evaluated in the current study included previously received vaccine type in the first two doses, socioeconomic characteristics, health status, knowledge about COVID-19 and its vaccines and adherence to protective practices. Results: Overall, 61.1% of participants expressed willingness to receive a COVID-19 booster dose, with a high median score of knowledge and practice toward COVID-19. Participants who did not perceive COVID-19 to be serious, p-value <0.001), participants who believed they would not be infected with COVID-19 in the next 6 months (p-value <0.001), low knowledge score group (p-value <0.001), lower education (p-value <0.001), participants who received the COVID-19 vaccine because of imposed laws (p-value <0.001), participants who received AstraZeneca vaccine (p-value <0.001), younger participants (p-value=0.003), low level of practice (p-value <0.001), participants who did not know someone who had died due to COVID-19 (p-value=0.01), low risk of developing serious side effects if infected with COVID-19 and participants in the low side effects score were significantly less frequently willing to receive a booster COVID-19 dose (p-value <0.001). The main reasons for booster dose hesitancy/refusal were the perceived lack of need for a booster shot, the uselessness of a booster shot and the conspiracy theory of boosting corporate profits through booster shots. Conclusion: There is high hesitancy towards COVID-19 booster dose acceptance among the Iraqi population. The study identified several factors associated with vaccine hesitancy including low socioeconomic status and low knowledge about COVID-19 and its vaccines.

20.
Cureus ; 14(5): e24927, 2022 May.
Article in English | MEDLINE | ID: covidwho-1903866

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 is the seventh member of the Coronaviridiae family of viruses, which are thought to be transmitted by Chinese horseshoe bats. The virus undergoes mutations leading to variants such as B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma), and B.1.617 (delta), as well as the recent variant B.1.1.529 (omicron), which has around 30 deletions, making it a severely mutated form that lowers vaccination-induced protection. Vaccine efficacy is usually expressed as relative risk reduction, which is based on the ratio of attack rates with and without a vaccine, whereas absolute risk reduction is based on the entire population. Rather than two doses, recent research suggests that a third dose/booster dose may aid in protection against future variants. The constant influx of mutant variations is putting a strain on vaccine production. Despite the challenges, we are optimistic that the epidemic will be eradicated by achieving mass immunity and by ensuring that everyone receives vaccines at a faster rate.

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