An Analysis of SARS-CoV-2 Vaccine Reactogenicity: Variation by Type, Dose, and History, Severity, and Recency of Prior SARS-CoV-2 Infection.

Background: There is limited information on the functional consequences of coronavirus disease 2019 (COVID-19) vaccine side effects. To support patient counseling and public health messaging, we describe the risk and correlates of COVID-19 vaccine side effects sufficient to prevent work or usual activities and/or lead to medical care ("severe" side effects). Methods: The EPICC study is a longitudinal cohort study of Military Healthcare System beneficiaries including active duty service members, dependents, and retirees. We studied 2789 adults who were vaccinated between December 2020 and December 2021. Results: Severe side effects were most common with the Ad26.COV2.S (Janssen/Johnson and Johnson) vaccine, followed by mRNA-1273 (Moderna) then BNT162b2 (Pfizer/BioNTech). Severe side effects were more common after the second than first dose (11% vs 4%; P < .001). First (but not second) dose side effects were more common in those with vs without prior severe acute respiratory syndrome coronavirus 2 infection (9% vs 2%; adjusted odds ratio [aOR], 5.84; 95% CI, 3.8-9.1), particularly if the prior illness was severe or critical (13% vs 2%; aOR, 10.57; 95% CI, 5.5-20.1) or resulted in inpatient care (17% vs 2%; aOR, 19.3; 95% CI, 5.1-72.5). Side effects were more common in women than men but not otherwise related to demographic factors. Conclusions: Vaccine side effects sufficient to prevent usual activities were more common after the second than first dose and varied by vaccine type. First dose side effects were more likely in those with a history of COVID-19-particularly if that prior illness was severe or associated with inpatient care. These findings may assist clinicians and patients by providing a real-world evaluation of the likelihood of experiencing impactful postvaccine symptoms.

Reactogenicity and Peak Anti-RBD-S1 IgG Concentrations in Individuals with No Prior COVID-19 Infection Vaccinated with Different SARS-CoV-2 Vaccines.

OBJECTIVE: To investigate the association of immune response with vaccination adverse effects at peak anti-receptor-binding domain spike subunit 1 (anti-RBDS1) IgG after full vaccination with Comirnaty, Spikevax, or Vaxzevria. METHODS: Anti-RBDS1 IgG concentrations after vaccination were determined in healthy adults vaccinated with the Comirnaty, Spikevax, and Vaxzevria vaccines. The association of reactogenicity and peak antibody response after vaccination was tested. RESULTS: Anti-RBDS1 IgG values were significantly higher in the Comirnaty and Spikevax group, compared with the Vaxzevria group (P < .001). Fever and muscle pain were found to be significant independent predictors of peak anti-RBDS1 IgG in the Comirnaty and Spikevax groups (P = .03 and P = .02, respectively). The multivariate model, adjusted for covariates, showed that no association between reactogenicity and peak antibody concentrations was found in the Comirnaty, Spikevax, and Vaxzevria groups. CONCLUSIONS: No association between reactogenicity and peak anti-RBDS1 IgG after vaccination with the Comirnaty, Spikevax, and Vaxzevria vaccine was found.

Safety and immunogenicity of SCB-2019, an adjuvanted, recombinant SARS-CoV-2 trimeric S-protein subunit COVID-19 vaccine in healthy 12-17 year-old adolescents.

We previously demonstrated the efficacy of the COVID-19 vaccine candidate, SCB-2019, in adults in the SPECTRA phase 2/3 efficacy study. We extended the study to include 1278 healthy 12-17-year-old adolescents in Belgium, Colombia, and the Philippines who received either two doses of SCB-2019 or placebo 21 days apart, to assess immunogenicity as neutralizing antibodies against prototype SARS-CoV-2 and variants of concern, and safety and reactogenicity as solicited and unsolicited adverse events with a comparator group of young adults (18-25 years). In participants with no evidence of prior SARS-CoV-2 infection SCB-2019 immunogenicity in adolescents was non-inferior to that in young adults; respective geometric mean neutralizing titers (GMT) against prototype SARS-CoV-2 14 days after the second vaccination were 271 IU/mL (95% CI: 211-348) and 144 IU/mL (116-178). Most adolescents (1077, 84.3%) had serologic evidence of prior SAR-CoV-2 exposure at baseline; in these seropositive adolescents neutralizing GMTs increased from 173 IU/mL (135-122) to 982 IU/mL (881-1094) after the second dose. Neutralizing titers against Delta and Omicron BA SARS-CoV-2 variants were also increased, most notably in those with prior exposure. SCB-2019 vaccine was well tolerated with generally mild or moderate, transient solicited and unsolicited adverse events that were comparable in adolescent vaccine and placebo groups except for injection site pain - reported after 20% of SCB-2019 and 7.3% of placebo injections. SCB-2019 vaccine was highly immunogenic against SARS-CoV-2 prototype and variants in adolescents, especially in those with evidence of prior exposure, with comparable immunogenicity to young adults. Clinical trial registration: EudraCT 2020-004272-17; ClinicalTrials.gov NCT04672395.

Evaluating the reactogenicity of COVID-19 vaccines from network-meta analyses.

BACKGROUND: Evidence-based reassurances addressing vaccine-related concerns are crucial to promoting primary vaccination, completion of the primary series, and booster vaccination. By summarizing and comparing the reactogenicity of COVID-19 vaccines authorized by the European Medicines Agency, this analysis aims to support in-formed decision-making by the lay public and help overcome vaccine hesitancy. RESEARCH DESIGN AND METHODS: A systematic literature review identified 24 records reporting solicited adverse events for AZD1222, BNT162b2, mRNA-1273, NVX-Cov2373, and VLA2001 in individuals aged 16 or older. Network meta-analyses were conducted for each solicited adverse events reported for at least two vaccines that were not compared head-to-head but could be connected through a common comparator. RESULTS: A total of 56 adverse events were investigated through network meta-analyses within a Bayesian framework with random-effects models. Overall, the two mRNA vaccines were found to be the most reactogenic vaccines. VLA2001 had the highest likelihood of being the least reactogenic vaccine after the first and second vaccine dose, especially for systemic adverse events after the first dose. CONCLUSIONS: The reduced chance of experiencing an adverse event with some COVID-19 vaccines may help to overcome vaccine hesitancy in population groups with concerns about the side effects of vaccines.

COVID-19 vaccine type-dependent differences in immunogenicity and inflammatory response: BNT162b2 and ChAdOx1 nCoV-19.

Evaluation of the safety and immunogenicity of new vaccine platforms is needed to increase public acceptance of coronavirus disease 2019 (COVID-19) vaccines. Here, we evaluated the association between reactogenicity and immunogenicity in healthy adults following vaccination by analyzing blood samples before and after sequential two-dose vaccinations of BNT162b2 and ChAdOx1 nCoV-19. Outcomes included anti-S IgG antibody and neutralizing antibody responses, adverse events, and proinflammatory cytokine responses. A total of 59 and 57 participants vaccinated with BNT162b2 and ChAdOx1 nCoV-19, respectively, were enrolled. Systemic adverse events were more common after the first ChAdOx1 nCoV-19 dose than after the second. An opposite trend was observed in BNT162b2 recipients. Although the first ChAdOx1 nCoV-19 dose significantly elevated the median proinflammatory cytokine levels, the second dose did not, and neither did either dose of BNT162b2. Grades of systemic adverse events in ChAdOx1 nCoV-19 recipients were significantly associated with IL-6 and IL-1ß levels. Anti-S IgG and neutralizing antibody titers resulting from the second BNT162b2 dose were significantly associated with fever. In conclusion, systemic adverse events resulting from the first ChAdOx1 nCoV-19 dose may be associated with proinflammatory cytokine responses rather than humoral immune responses. Febrile reactions after second BNT162b2 dose were positively correlated with vaccine-induced immune responses rather than with inflammatory responses.

Influence of epidemiological and clinical factors in the reactogenicity to Comirnaty® vaccine in health care workers of a Spanish university teaching hospital (COVIVAC study).

OBJECTIVE: Comirnaty® is an mRNA vaccine against COVID-19 which has been administered to millions of people since the end of 2020. Our aim was to study epidemiological and clinical factors influencing reactogenicity and functional limitation after the first two doses of the vaccine in health care workers (HCWs). METHODS: Prospective post-authorization cohort study to monitor safety and effectiveness of the vaccine. RESULTS: Local side effects were mild and presented both with first and second dose of Comirnaty. Systemic side effects were more frequent after 2nd dose. Nevertheless, previous SARS-CoV-2 infection was associated with systemic effects after the first dose of the vaccine (OR ranging from 2 to 6). No severe adverse effects were reported. According to multivariate analysis, the degree of self-reported functional limitation after the first dose increased with age, female sex, previous COVID-19 contact, previous SARS-CoV-2 infection, and Charlson Comorbidity Index (CCI). After the second dose, the degree of functional limitation observed was lower in those with previous SARS-CoV-2 infection, and it was positively associated to the degree of functional limitation after the first dose. CONCLUSIONS: Systemic adverse effects were more frequent after the second dose of Comirnaty. Previous SARS-CoV-2 infection was associated with systemic effects after the first dose. Age, female sex, previous COVID-19, previous isolation due to COVID-19 contact, and CCI showed to be independent predictors of the degree of functional limitation after the 1st dose of Comirnaty®. After the 2nd dose, the degree of functional limitation was lower in those who previously had SARS-CoV-2 infection.

Correlation of adverse effects and antibody responses following homologous and heterologous COVID19 prime-boost vaccinations.

BACKGROUND: Studies correlating reactogenicity and immunogenicity of COVID-19 vaccines are limited to BNT162b2, with inconsistent results. We investigated whether adverse reactions after other COVID-19 vaccines reliably predict humoral responses. METHODS: Adult volunteers were recruited for homologous or heterologous prime-boost vaccinations with adenoviral (ChAdOx1, AstraZeneca) and/or mRNA (mRNA-1273, Moderna) vaccines administered either 4 or 8 weeks apart. Adverse effects were routinely solicited and recorded by subjects in a standard diary card for up to 84 days post booster vaccination. Anti-SARS-CoV-2 IgG titers were measured pre- (visit 1), and post-booster dose at days 14 (visit 2) and 28 (visit 3). RESULTS: A total of 399 participants (75% women) with a median age of 41 (interquartile range, 33-48 IQR) years were included. Vaccine-induced antibody titers at days 14 and 28 were significantly higher among subjects who reported local erythema, swelling, pain, as well as systemic fever, chills, headache, myalgia, arthralgia, fatigue compared to those who did not experience local or systemic reactogenicity. Post-vaccination humoral responses did not correlate with the occurrence of skin rash and correlated weakly with gastrointestinal symptoms. A significant correlation between post-vaccination peak body temperature and anti-SARS-CoV-2 spike IgG at Day 14, independent of vaccine type and schedule, was found. CONCLUSION: Specific symptoms of reactogenicity such as post-vaccination injection site pain, swelling, erythema and fever, myalgia and fatigue are significantly predictive of the magnitude of the anti-SARS-CoV-2 antibody response.

Predictors for reactogenicity and humoral immunity to SARS-CoV-2 following infection and mRNA vaccination: A regularized, mixed-effects modelling approach.

Introduction: The influence of pre-existing humoral immunity, inter-individual demographic factors, and vaccine-associated reactogenicity on immunogenicity following COVID vaccination remains poorly understood. Methods: Ten-fold cross-validated least absolute shrinkage and selection operator (LASSO) and linear mixed effects models were used to evaluate symptoms experienced by COVID+ participants during natural infection and following SARS-CoV-2 mRNA vaccination along with demographics as predictors for antibody (AB) responses to recombinant spike protein in a longitudinal cohort study. Results: In previously infected individuals (n=33), AB were more durable and robust following primary vaccination when compared to natural infection alone. Higher AB were associated with experiencing dyspnea during natural infection, as was the total number of symptoms reported during the COVID-19 disease course. Both local and systemic symptoms following 1st and 2nd dose (n=49 and 48, respectively) of SARS-CoV-2 mRNA vaccines were predictive of higher AB after vaccination. Lastly, there was a significant temporal relationship between AB and days since infection or vaccination, suggesting that vaccination in COVID+ individuals is associated with a more robust immune response. Discussion: Experiencing systemic and local symptoms post-vaccine was suggestive of higher AB, which may confer greater protection.

Cohort event monitoring for safety signal detection in adult individuals 18 years and above after immunisation with coronavirus disease 2019 vaccines in Nigeria.

Introduction: In Nigeria, immunisation with coronavirus disease 2019 (COVID-19) vaccines commenced in March 2021. COVISHIELD from AstraZeneca (AZ), a viral vector vaccine, was the brand administered in the first phase of vaccinations for pre-determined eligible adults 18 years and above. As more brands of COVID-19 vaccines have been introduced in Nigeria, identifying effective and safe vaccine brands is essential to pharmacovigilance and public health. The current study assessed the safety of the AZ-AZD1222 (ChAdOx1) COVID-19 vaccine in adults during the first phase of the vaccination exercise in Nigeria. Methodology: We conducted a descriptive analysis of safety data from selected vaccination sites across six states in Nigeria between June 2021 and September 2021. Respondents were monitored over 3 months for local and systemic reactions, as well as hospitalisation and mortality. Measures obtained from respondents include age, sex, pre-existing comorbidity, local and systemic reactions to vaccines, timing onset of reactions, hospitalisation and mortality. Bivariate and multivariable regression models were used to assess factors associated with vaccine reactogenicity. Results: A total of 1284 individuals were enrolled in the cohort study from the six selected states (Anambra, Borno, Edo, Katsina, Lagos and Plateau) representing the geopolitical zones of Nigeria. A total of 675 individuals or 52.6% of enrolees reported non-serious adverse effects, and only one individual or 0.08% reported a serious adverse event following immunisation in the first 7 days after vaccination. None of the enrolled participants reported adverse events requiring hospitalisation. The most common self-reported symptoms amongst vaccine recipients were tenderness at the injection site 20.9% and fever 20.3%. A majority of symptoms (55.5%) occurred on or before the 3rd day after vaccination. Multivariable logistic regression model showed that age 60 years or above (vs. 18-24 years) was significantly associated with a lower likelihood of a vaccine-related symptomatic reaction (adjusted odds ratio: 0.35; 95% confidence interval: 0.20-0.61). There was no reported mortality amongst all the enrolled and followed-up vaccine recipients. Conclusion: Our findings suggest that the safety profile of the AZ vaccine is acceptable, and the observed symptoms were mild and mostly within the first 3 days following vaccination. Vaccine recipients will benefit from counselling about potential transient reactions, and improving public awareness can potentially encourage the uptake of vaccines and reduce the spread of the COVID-19 pandemic.

Reactogenicity within the first week after Sinopharm, Sputnik V, AZD1222, and COVIran Barekat vaccines: findings from the Iranian active vaccine surveillance system.

BACKGROUND: This study aimed to evaluate the reactogenicity effects of COVID-19 vaccines, used in Iran. METHODS: At least 1000 people were followed up with phone calls or self-report in a mobile application within 7 days after vaccination. Local and systemic reactogenicities were reported overall and by subgroups. RESULTS: The presence of one or more local and systemic adverse effects after the first dose of vaccines was 58.9% [(95% Confidence Intervals): 57.5-60.3)] and 60.5% (59.1-61.9), respectively. These rates were reduced to 53.8% (51.2-55.0) and 50.8% (48.8-52.7) for the second dose. The most common local adverse effect reported for all vaccines was pain in the injection site. During the first week after the first dose of vaccines, the frequency of the pain for Sinopharm, AZD1222, Sputnik V, and Barekat was 35.5%, 86.0%, 77.6%, and 30.9%, respectively. The same rates after the second dose were 27.3%, 66.5%, 63.9%, and 49.0%. The most common systemic adverse effect was fatigue. In the first dose, it was 30.3% for Sinopharm, 67.4% for AZD1222, 47.6% for Sputnik V, and 17.1% for Barekat. These rates were reduced to 24.6%, 37.1%, 36.5%, and 19.5%, in the second dose of vaccines. AZD1222 had the highest local and systemic adverse effects rates. The odds ratio of local adverse effects of the AZD1222 vaccine compared to the Sinopharm vaccine were 8.73 (95% CI 6.93-10.99) in the first dose and 4.14 (95% CI 3.32-5.17) in the second dose. Barekat and Sinopharm had the lowest frequency of local and systemic adverse effects. Compared to Sinopharm, systemic adverse effects were lower after the first dose of Barekat (OR = 0.56; 95% CI 0.46-0.67). Reactogenicity events were higher in women and younger people. Prior COVID-19 infection increased the odds of adverse effects only after the first dose of vaccines. CONCLUSIONS: Pain and fatigue were the most common reactogenicities of COVID-19 vaccination. Reactogenicities were less common after the second dose of the vaccines. The adverse effects of AZD1222 were greater than those of other vaccines.

Systemic reactogenicity following homologues and heterologous prime-boost AZD1222 and BNT162b2 COVID-19 vaccination of 2862 healthcare workers compared with an unvaccinated population.

During spring 2021, AZD1222 and BNT162b2 were used as prime and BNT162b2 as booster COVID-19 vaccines in Denmark. We obtained self-reported information on systemic reactogenicity day-by-day during two weeks for 2862 healthcare workers vaccinated with heterologous AZD1222 + BNT162b2 or homologous BNT162b2 + BNT162b2 regimens and compared prevalences of symptoms with unvaccinated healthcare workers. We found comparable systemic reactogenicity during the first week in the two vaccine regimens and no reactogenicity during the second week. Most of the symptoms returned to a level equal to the control population four days after booster vaccination.

COVID-19 vaccination in pregnancy.

Despite a recent endorsement from official and professional bodies unequivocally recommending COVID-19 vaccination, vaccine hesitancy among pregnant people remains high. The accumulated evidence demonstrates that pregnant people are a special risk group for COVID-19, with an increased risk of intensive care unit admission, extracorporeal membranous oxygenation requirement, preterm birth, and perinatal death. These risks are further increased with some variants of concern, and vaccination of pregnant people reduces the COVID-19-related increase in maternal or fetal morbidity. Data from more than 180,000 vaccinated persons show that immunization against COVID-19 with an mRNA vaccine is safe for pregnant people. Many observational studies comparing perinatal outcomes between vaccinated and unvaccinated pregnant people have had reassuring findings and did not demonstrate harmful effects on pregnancy or the newborn. Immunization with mRNA vaccines does not increase the risk of miscarriage, preterm delivery, low birthweight, maternal or neonatal intensive care unit admission, fetal death, fetal abnormality, or pulmonary embolism. Moreover, observational data corroborate the findings of randomized trials that mRNA vaccination is highly effective at preventing severe SARS-CoV-2 infection in pregnant people, emphasizing that the potential maternal and fetal benefits of vaccination greatly outweigh the potential risks of vaccination. Ensuring pregnant people have unrestricted access to COVID-19 vaccination should be a priority in every country worldwide.

Examining the association between vaccine reactogenicity and antibody titer dynamics after the third dose of BNT162b2 vaccine using a mixed-effects model

Background: To mitigate the COVID-19 pandemic, many countries have recommended the use of booster vaccinations. The relationship between the degree of adverse vaccine reactions and elevated antibody titers is of interest;however, no studies have investigated the temporal changes in antibody titers based on repeated measurements after a third dose of the BNT162b2 vaccine. Methods: This prospective longitudinal cohort study was conducted with 62 healthcare workers who received a third dose of the BNT162b2 at Okayama University Hospital, Japan. Venous blood draw and fingertip whole blood test sample collection were conducted at the early (3–13 days) and 1-month time points;only FWT sample collection was conducted at the 2-month time point. Information on adverse reactions within 1 week after vaccination was also obtained. The association between fever of 37.5 °C or higher and antibody titers after the third dose of BNT162b2 was examined using a mixed-effects model and Poisson regression with robust variance. Results: A trend toward higher antibody titers in the early period after vaccination was observed in the febrile individuals, but the differences were not significant at 1 and 2 months post-vaccination (the partial regression coefficient for fever was 8094.3 [-1910.2, 18,098.8] at 1 month after vaccination, and 1764.1 [-4133.9, 7662.1] at 2 months after vaccination in the adjusted models). Conclusion: The findings suggest that the presence of fever after the third vaccine does not predict a sustained elevation in serum antibody titers. © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases

Associations of Immunogenicity and Reactogenicity After SARS-CoV-2 mRNA-1273 Vaccine in COVE and TeenCOVE Trials.

BACKGROUND: The reactogenicity and immunogenicity of Coronavirus 2019 (COVID-19) vaccines is well-studied. Little is known regarding the relationship between immunogenicity and reactogenicity of COVID-19 vaccines. METHODS: This study assessed the association between immunogenicity and reactogenicity after two mRNA-1273 (100 µg) injections in 1671 total adolescent and adult participants (≥12 years) from the primary immunogenicity sets of the blinded periods of the Coronavirus Efficacy (COVE) and TeenCOVE trials. Associations between immunogenicity through day 57 and solicited ARs after the first and second injections of mRNA-1273 were evaluated among participants with and without solicited ARs using linear mixed-effects models. RESULTS: The mRNA-1273 reactogenicity in this combined analysis set was similar to that reported for these trials. The vaccine elicited high neutralizing antibody (nAb) geometric mean titers (GMTs) in evaluable participants. GMTs at day 57 were significantly higher in participants who experienced solicited systemic ARs after the second injection (1227.2 [1164.4-1293.5]) than those who did not (980.1 [886.8-1083.2], p = 0.001) and were associated with fever, chills, headache, fatigue, myalgia, and arthralgia. Significant associations with local ARs were not found. CONCLUSIONS: These data show an association of systemic ARs with increased nAb titers following a second mRNA-1273 injection. While these data indicate systemic ARs are associated with increased antibody titers, high nAb titers were observed in participants after both injections, consistent with the immunogenicity and efficacy in these trials. These results add to the body of evidence regarding the relationship of immunogenicity and reactogenicity and can contribute toward the design of future mRNA vaccines.

Heterologous prime-boost immunization with ChAdOx1-S and BNT162b2: reactogenicity and immunogenicity in a prospective cohort study.

OBJECTIVES: Regarding reactogenicity and immunogenicity, heterologous COVID-19 vaccination regimens are considered as an alternative to conventional immunization schemes. METHODS: Individuals receiving either heterologous (ChAdOx1-S [AstraZeneca, Cambridge, UK]/BNT162b2 [Pfizer-BioNTech, Mainz, Germany]; n = 306) or homologous (messenger RNA [mRNA]-1273 [Moderna, Cambridge, Massachusetts, USA]; n = 139) vaccination were asked to participate when receiving their second dose. Reactogenicity was assessed after 1 month, immunogenicity after 1, 3, and/or 6 months, including a third dose, through SARS-CoV-2 antispike immunoglobulin G, surrogate virus neutralization test, and a plaque reduction neutralization test against the Delta (B.1.167.2) and Omicron (B.1.1.529; BA.1) variants of concern. RESULTS: The overall reactogenicity was lower after heterologous vaccination. In both cohorts, SARS-CoV-2 antispike immunoglobulin G concentrations waned over time with the heterologous vaccination demonstrating higher neutralizing activity than homologous mRNA vaccination after 3 months to low neutralizing levels in the Delta plaque reduction neutralization test after 6 months. At this point, 3.2% of the heterologous and 11.4% of the homologous cohort yielded low neutralizing activity against Omicron. After a third dose of an mRNA vaccine, ≥99% of vaccinees demonstrated positive neutralizing activity against Delta. Depending on the vaccination scheme and against Omicron, 60% to 87.5% of vaccinees demonstrated positive neutralizing activity. CONCLUSION: ChAdOx1-S/BNT162b2 vaccination demonstrated an acceptable reactogenicity and immunogenicity profile. A third dose of an mRNA vaccine is necessary to maintain neutralizing activity against SARS-CoV-2. However, variants of concern-adapted versions of the vaccines would be desirable.

Immunogenicity and Safety of Vaccines against Coronavirus Disease in Actively Treated Patients with Solid Tumors: A Prospective Cohort Study.

PURPOSE: We aimed to assess the humoral response to and reactogenicity of coronavirus disease 2019 (COVID-19) vaccination according to the vaccine type and to analyze factors associated with immunogenicity in actively treated solid cancer patients (CPs). Materials and Methods: Prospective cohorts of CPs, undergoing anticancer treatment, and healthcare workers (HCWs) were established. The participants had no history of previous COVID-19 and received either mRNA-based or adenovirus vector-based (AdV) vaccines as the primary series. Blood samples were collected before the first vaccination and after 2 weeks for each dose vaccination. Spike-specific binding antibodies (bAbs) in all participants and neutralizing antibodies (nAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) wild-type, Delta, and Omicron variants in CPs were analyzed and presented as the geometric mean titer. RESULTS: Age-matched 20 HCWs and 118 CPs were included in the analysis. The bAb seroconversion rate and antibody concentrations after the first vaccination were significantly lower in CPs than in HCWs. After the third vaccination, antibody levels in CPs with a primary series of AdV were comparable to those in HCWs, but nAb titers against the Omicron variant did not quantitatively increase in CPs with AdV vaccine as the primary series. The incidence and severity of adverse reactions post-vaccination were similar between CPs and HCWs. CONCLUSION: CPs displayed delayed humoral immune response after SARS-CoV-2 vaccination. The booster dose elicited comparable bAb concentrations between CPs and HCWs, regardless of the primary vaccine type. Neutralization against the Omicron variant was not robustly elicited following the booster dose in some CPs, implying the need for additional interventions to protect them from COVID-19.

Really just a little prick? A meta-analysis on adverse events in placebo control groups of seasonal influenza vaccination RCTs.

BACKGROUND: The Corona pandemic and ongoing mass vaccinations raise the question of the nocebo mechanisms involved. Since immunization is usually administered to healthy people as a preventive health measure, adverse events (AE) following immunization are less accepted and could contribute to vaccine hesitancy. Assuming that vaccinees experience nocebo responses, the aim of this meta-analysis was to investigate the effect sizes of solicited adverse events (or assumed reactogenicity) reported in placebo groups in RCTs on seasonal influenza vaccination. METHODS: Literature search via PubMed, Web of Science, and CENTRAL was conducted considering gray literature. Only RCTs with placebo groups using pharmacologically inert substances (like saline) were included. Quality was assessed using Cochrane Collaboration's Risk of Bias Tool. Effect sizes were estimated using a random mixed effects model based on k = 31 studies covering 14,326 participants in placebo groups. RESULTS: Reported solicited AEs in placebo groups showed significant effect sizes of proportions (ESp). In k = 13 analyzed placebo groups, 35 % of the participants reported at least one solicited systemic AE (p = 0.007). The most common particular solicited systemic AEs were headache (k = 27; 17 %; p = 0.001), malaise (k = 13; 12 %; p = 0.004), and hyperhidrosis (k = 4; 12 %; p < 0.001) within one week after vaccination. CONCLUSION: The results show significant solicited AEs in placebo groups, indicating substantial nocebo responses after vaccination. Based on the fact that most vaccination programs include similar groups of healthy people, we expect that comparable nocebo effects occur during other campaigns. Health care professionals should be aware of the nocebo response and take action to prevent or decrease the burden of adverse events following immunization. Fear of side effects must be addressed early in order to diminish vaccine hesitancy. Prospero identifier: CRD42020156287, October 2019.

Association of a third vaccination with antibody levels and side reactions in essential workers: A prospective cohort study.

OBJECTIVE: To evaluate the relationship between the change of titer and adverse events after the third vaccination for COVID-19 among healthcare workers. DESIGN AND SETTING: This was a prospective cohort study, and the follow-up period was from December 2021 to November 2023. PARTICIPANTS: A total of 392 healthcare workers aged over 20 years who worked at the facility and wished to have vaccine antibody titers measured participated in this study. EXPOSURES: A third dose of BNT162b2 COVID-19 vaccine was administered to healthcare workers working at the hospital, and we evaluated the changes in antibody titers before and after the vaccine, as well as adverse reactions after vaccination. MAIN OUTCOMES AND MEASURES: The primary endpoints were adverse reactions within 7 days after the third dose of COVID-19 vaccine and the rate of increase in COVID-19 vaccine antibody titer at 4 weeks. RESULTS: A total of 392 people participated in the study, of whom 358 participants had their antibody titers measured before and after the booster vaccination. The overall IgG geometric mean was 609 U/mL (561-663) before booster vaccination and increased to 18,735 U/mL (17,509-20,049) at 4 weeks after vaccination (p < 0.001). Multivariate analysis showed no statistically significant relationship between the primary endpoints, such as a change in antibody titer due to the presence of fever after vaccination or a change in antibody titer due to swelling at the vaccination site. Factors affecting the rate of increase in antibody titer, evaluated as secondary endpoints, were suggested to be age (1.02 (95 % confidence interval (CI): 1.01-1.03)) and hypertension (0.66 (95 % CI: 0.47-0.93)). CONCLUSIONS AND RELEVANCE: In relation to the booster effect of the third dose of COVID-19 vaccination, there was no statistically significant difference in the presence of fever or use of antipyretic or other drugs.

Multimorbidity and Its Effect on Self-Reported Adverse Effects Following COVID-19 Vaccination.

Introduction The coronavirus disease 2019 (COVID-19) vaccination has been suggested for those with comorbidities, although there are concerns regarding the vaccine's safety. This study aimed to compare the severity and incidence of post-vaccination side effects in people with and without comorbidities. Another aim of this study was also to look for the effect of multimorbidity on adverse events. Methods This observational study was conducted from November 2021 to February 2022. Data were collected from all over Pakistan using a self-administered online questionnaire that inquired about the subject's demographic, clinical, and COVID-19 vaccination profiles. Data analysis was done by using SPSS software version 22.0. (Chicago, IL, IBM Corp.). Results A total of 421 participants were included in the study, and 31.4% of individuals had underlying comorbidity. The overall mean age was 33 years (range: 13-85 years). This study included recipients of all major types of COVID-19 vaccines being used in Pakistan. Only 67.4% of the subjects had only underlying comorbidity, and hypertension was the most common one out of all comorbidities. Participants with comorbidities were not at a greater risk to produce vaccine-related adverse events when compared to those with no comorbidities. Comorbidity was also found to be statistically non-significant to the severity of the side effects. Only one subject with comorbidity produced a side effect and required hospitalization. Multimorbidity was not associated with a greater incidence of side effects. Multimorbidity was not significantly linked with the severity of the adverse effects, except muscle pain (p<0.05) and breathlessness (p<0.05). Conclusion It can be concluded that comorbidities do not affect the COVID-19 vaccine's reactogenicity but studies on an extensive scale should be conducted regarding individuals with multiple pre-existing comorbidities.