Characteristics and outcomes of adverse events after COVID-19 vaccination.

OBJECTIVES: BNT-162b2, mRNA-1273, and Ad26.COV2.S vaccines data regarding adverse events (AEs) are scarce. In this report, we aimed to describe fatal and non-fatal possible AEs after COVID-19 vaccine administration. METHODS: An observational multicenter study investigating the causes of emergency department visits and hospital admissions within 10 days of COVID-19 vaccination. Patients who received first or second doses of COVID-19 vaccines and presented to the emergency department (ED), as well as those admitted to the hospitals or intensive care units (ICUs) were included. Causes of ED, hospital, and ICU admissions and discharges were collected based on the International Classification of Diseases, Tenth Revision (ICD-10) coding system. RESULTS: Between December 2020 and March 2021, 1842 patients visited the ED within 10 days of COVID-19 vaccine administration. The mean age was 70.3 years. Overall, 1221 patients presented after the first dose of the vaccine and 653 after the second dose. Trauma (14.9%), hypertensive emergency/urgency (7.8%), generalized pain and arthralgia (5.7%), and chest pain (4.4%) were the most common causes of presentation to the ED. Of all ED presentations, mortality rate was at 2.2% (41 patients) with a median follow-up time of 68.0 days, versus 2.6% in unvaccinated ED patients. Postvaccination acute hypoxemic respiratory failure (46.3%), septic shock (24.4%), and cardiogenic shock (12.2%) were the most common causes of death. CONCLUSION: Although reported AEs are not necessarily caused by the vaccination, this study provides further information about possible AEs after COVID-19 immunization, especially those requiring hospital admission. This study also supports prior data that serious AEs post vaccination are much lower than primary COVID-19 infections. Further studies are needed to investigate causalities between vaccines and reported AEs across all age groups.

Vaccine confidence among those living with allergy during the COVID pandemic (ACCORD): A scoping review.

Background: Reports of allergic reactions to coronavirus disease 2019 (COVID-19) vaccines, coupled with an "infodemic" of misinformation, carry the potential to undermine confidence in the COVID-19 vaccines. However, no attempts have been made to comprehensively synthesize the literature on how allergic disease and fear of allergic reactions to the vaccines contribute to hesitancy. Objectives: Our aim was to review the academic and gray literature on COVID-19 vaccine hesitancy and allergic reactions. Methods: We searched 4 databases (CINAHL, PsycINFO, MEDLINE, and Embase) using a search strategy developed by content and methodologic experts. No restrictions were applied regarding COVID-19 vaccine type, country of study, or patient age. Eligible articles were restricted to 10 languages. Results: Of the 1385 unique records retrieved from our search, 60 articles (4.3%) were included. Allergic reactions to the COVID-19 vaccine were rare but slightly more common in individuals with a history of allergic disease. A fifth of the studies (13 of 60 [22%]) discussed vaccine hesitancy due to possibility of an allergic reaction. Additionally, the present review identified research on details of vaccine-related anaphylaxis (eg, a mean and median [excluding clinical trial data] of 12.4 and 5 cases per million doses, respectively) and allergic reactions (eg, a mean and median [excluding clinical trial data] of 489 and 528 cases per million doses, respectively). Conclusion: COVID-19 vaccine acceptance among individuals living with allergy and among those with no history of allergic disease may be affected by fear of an allergic reaction. Despite the low incidence of allergic reactions to the COVID-19 vaccine, fear of such reactions is one of the most commonly cited concerns reported in the literature.

Etiology model for many vaccination adverse reactions, including SARS-CoV-2 spike vaccines

Objective: Vaccinated individuals (vaccinees) experience no adverse events, mild adverse events, multiple adverse events, or serious adverse events post vaccination. Many of these vaccine adverse events occur with different vaccines with different occurrence frequencies. Many of these adverse events are generally considered as associated with immune responses to the active vaccine components (antigens) and/or to possibly one or more of the vaccine excipients. Most of these vaccine adverse events are self-limiting and resolve within days. The number of vaccine adverse reactions is higher for SARS-CoV-2 spike vaccines than all other vaccines. Can data analysis of vaccine adverse reactions responses provide etiology insights for high reactogenicity vaccines? Methods: The Vaccine Adverse Event Reporting System (VAERS) database was data mined for all vaccine adverse events data by vaccine, age, gender, dose, and day of onset post vaccination. Results for vaccines with the highest number of adverse events were compared. Results: For vaccines and adverse events with the highest numbers of reports, the day of onset approximates a power of two decay pattern for the first three days. The consistency of this pattern for multiple unrelated vaccines narrows possible etiology mechanisms. Many of these adverse event symptoms overlap symptoms associated with elevated histamine levels. Herein, innate immune responses and specifically elevated histamine levels are proposed to be causative for the majority of these adverse events. This hypothesis is based on a model of innate immune responses releasing a surge of inflammatory molecules, including histamine;this surge is hypothesized to exceed the normal histamine tolerance level for vaccinees causing reactogenicity adverse events. Further, these symptoms resolve as histamine levels fall below the vaccinee's tolerance threshold. This model can be evaluated by the detection of elevated histamine levels in vaccinees corresponding to timing of symptoms onset. If confirmed, a direct consequence of this model predicts that specific antihistamine treatments, mast cell stabilizers, and possibly diamine oxidase enzyme may reduce the incidence or severity of adverse events experienced by vaccinees post vaccinations for most or all high reactogenicity vaccines including coronavirus disease 2019 (COVID-19) spike vaccines. Conclusions: The reported onset occurrences of the majority of reported adverse events are consistent with the likely etiology of innate immune responses to vaccinations for vaccines with higher reactogenicity levels. Herein, the hypothesis is proposed that the majority of these adverse events result from a histamine surge that temporarily exceeds the vaccinee's tolerance level.

Serious adverse events of special interest following mRNA COVID-19 vaccination in randomized trials in adults.

INTRODUCTION: In 2020, prior to COVID-19 vaccine rollout, the Brighton Collaboration created a priority list, endorsed by the World Health Organization, of potential adverse events relevant to COVID-19 vaccines. We adapted the Brighton Collaboration list to evaluate serious adverse events of special interest observed in mRNA COVID-19 vaccine trials. METHODS: Secondary analysis of serious adverse events reported in the placebo-controlled, phase III randomized clinical trials of Pfizer and Moderna mRNA COVID-19 vaccines in adults (NCT04368728 and NCT04470427), focusing analysis on Brighton Collaboration adverse events of special interest. RESULTS: Pfizer and Moderna mRNA COVID-19 vaccines were associated with an excess risk of serious adverse events of special interest of 10.1 and 15.1 per 10,000 vaccinated over placebo baselines of 17.6 and 42.2 (95 % CI -0.4 to 20.6 and -3.6 to 33.8), respectively. Combined, the mRNA vaccines were associated with an excess risk of serious adverse events of special interest of 12.5 per 10,000 vaccinated (95 % CI 2.1 to 22.9); risk ratio 1.43 (95 % CI 1.07 to 1.92). The Pfizer trial exhibited a 36 % higher risk of serious adverse events in the vaccine group; risk difference 18.0 per 10,000 vaccinated (95 % CI 1.2 to 34.9); risk ratio 1.36 (95 % CI 1.02 to 1.83). The Moderna trial exhibited a 6 % higher risk of serious adverse events in the vaccine group: risk difference 7.1 per 10,000 (95 % CI -23.2 to 37.4); risk ratio 1.06 (95 % CI 0.84 to 1.33). Combined, there was a 16 % higher risk of serious adverse events in mRNA vaccine recipients: risk difference 13.2 (95 % CI -3.2 to 29.6); risk ratio 1.16 (95 % CI 0.97 to 1.39). DISCUSSION: The excess risk of serious adverse events found in our study points to the need for formal harm-benefit analyses, particularly those that are stratified according to risk of serious COVID-19 outcomes. These analyses will require public release of participant level datasets.

Risk Factors and Incidence Rates of Self-Reported Short-Term Adverse Events of COVID-19 Vaccine Booster Dose.

With the spread of the new SARS-CoV-2 variants, many countries have begun COVID-19 vaccine booster programs with the mix-and-match strategy. However, research on the adverse events (AE) of booster doses is still scarce. The aim of our study was to analyze the reported incidence rate (IR), and factors associated with AE, including short-term serious adverse events (SAE) and short-term non-serious adverse events (NSAE), among different vaccine products through the hospital-based Vaccine Adverse Event Reporting System (VAERS). A total of 7432 records were collected during the three-month study period. While more than half of the responses (52.2%) reported the presence of AE after receiving a booster dose, only a few AE were considered SAE (2.4%). AE were significantly higher among women and people of younger age, and the brand of vaccines is the strongest factor associated with post-booster dose AE. The incidence of AE in mRNA1273 is higher than in BNT162b2 and MVC-COV1901 (IRR mRNA1273 vs. BNT162b2: 1.22, 95% CI: 1.11-1.34; BNT162b2 vs. MVC-COV1901: 2.77, 95% CI: 2.27-3.39). The IR of different groups were calculated to support the decision making of the booster vaccine. Although AE were not uncommon for booster vaccines, almost all AE were not serious and predictable using estimated IR. This result can be used to optimize booster vaccine decision making.

Elevated Histamine Etiology Model for Most Major Vaccine Associated Adverse Events including SARS-CoV-2 Spike Vaccines.

Vaccinees experience no adverse events, mild adverse events, multiple adverse events, or serious adverse events post vaccination. Many of these vaccine adverse events occur with different vaccines with different occurrence frequencies. Many of these adverse events are generally considered as associated with immune responses to the active vaccine components (antigens) and/or to possibly one or more of the vaccine excipients. Most of these vaccine adverse events are self-limiting and resolve within days. Many of these adverse events symptoms overlap symptoms associated with elevated histamine levels. Based on these observations, the hypothesis that the majority of vaccine associated reactogenicity adverse events are caused by temporal histamine intolerance in vaccinees is proposed. This hypothesis is based on a model of innate immune responses releasing a surge of inflammatory molecules including histamine; this surge is hypothesized to exceed the normal histamine tolerance level for vaccinees with reactogenicity adverse events. Further, these symptoms resolve as histamine levels fall below the vaccinee's tolerance threshold. This model can be evaluated by the detection of elevated histamine levels in vaccinees corresponding to timing of symptoms onset. If confirmed, a direct consequence of this model predicts that some antihistamine treatments, mast cell stabilizers, and possibly diamine oxidase enzyme may reduce the incidence or severity of adverse events experienced by vaccinees post vaccinations for most or all high reactogenicity vaccines including coronavirus disease 2019 (COVID-19) Spike vaccines.

A Meta-Analysis of Safety of Different Regimens of Remdesivir in COVID-19 Patients.

Remdesivir is an adenosine analogue drug that targets RNA-dependent RNA polymerase enzyme and inhibits viral replication. As of 22nd October, 2020, US FDA fully approved the drug Remdesivir for the treatment of COVID-19 patients who requires hospitalisation. Many clinical studies reported the derangement in hepatic and renal function tests, which is alarming considering the health conditions of the COVID-19 patients. In view of these results, the present study was envisaged to review the safety of Remdesivir in COVID-19 patients. The PubMed, Embase, and Cochrane databases were searched using the terms 'Remdesivir,' 'veklury,' 'SARS' and 'COVID' till 1st December, 2020. The studies included in this meta-analysis were either randomised or nonrandomised studies that evaluated Remdesivir for the treatment of COVID-19 against Placebo [standard of care]. The Adverse events [AEs], Serious adverse events [SAEs] and Treatment Discontinuation due to Adverse Events (TDAE) were used as primary outcome measures. The quality of studies was evaluated by using the Cochrane Collaboration's tool for the assessment of RoB. Data analysis was performed by two authors (MK & DB) using statistical software Review manager [Revman] version 5.3. The pooled Risk Ratios (RR) and 95% Confidence Intervals (CI) were calculated by using a random-effects model for both primary and secondary outcomes. A total of four RCTs were included for the meta-analysis. Out of the four included clinical trials accepted for its methodological quality, three were of excellent quality and one study was of moderate quality. The pooled estimates of the three studies showed that Remdesivir had a 24% lower risk of SAEs compared to the placebo arm. However, the pooled estimates of two studies showed that 10 days of Remdesivir had 56% higher risk of SAEs compared to 5 days of Remdesivir regimen. Similarly, the 10 days of Remdesivir had two times higher risk of TDAEs compared to 5 days Remdesivir regimen. In conclusion, our meta-analysis demonstrated that Remdesivir is a safe therapeutic option. Our metanalysis revealed 5 days' regimen have better safety profile than 10 days' regimen of drug Remdesivir with respect to SAEs and TDAEs. For hospitalized patients, a 5-day course could be preferable with fewer safety concerns and lower drug costs. PROSPERO Registration ID: CRD 42020224272.