Safety and Efficacy of the Modified Vaccinia Ankara-Bavaria Nordic Vaccine Against Mpox in the Real World: Systematic Review and Meta-Analysis.

In May 2022, mpox began to spread worldwide, posing a serious threat to human public health. Modified Vaccinia Ankara-Bavaria Nordic (MVA-BN) is a live attenuated orthopoxvirus vaccine that has been authorized by the U.S. Food and Drug Administration as the vaccine of choice for the prevention of mpox. In this study, we conducted a meta-analysis of all currently published literature on the efficacy and safety of the MVA-BN vaccine in the real world, showing that the MVA-BN vaccine is effective and safe, with efficacy of up to 75% with a single dose and up to 80% with a two-dose vaccine. Meanwhile, we found that subcutaneous injection has lower local and systemic adverse events than intradermal injection, regardless of single- or two-dose vaccination, and subcutaneous injection is better tolerated in children, the elderly, or people with underlying medical conditions. These results have important reference value for clinical practice.

Investigation of the safety and protective efficacy of an attenuated and marker M. bovis-BoHV-1 combined vaccine in bovines.

Bovine respiratory disease (BRD) is one of the most common diseases in the cattle industry worldwide; it is caused by multiple bacterial or viral coinfections, of which Mycoplasma bovis (M. bovis) and bovine herpesvirus type 1 (BoHV-1) are the most notable pathogens. Although live vaccines have demonstrated better efficacy against BRD induced by both pathogens, there are no combined live and marker vaccines. Therefore, we developed an attenuated and marker M. bovis-BoHV-1 combined vaccine based on the M. bovis HB150 and BoHV-1 gG-/tk- strain previously constructed in our lab and evaluated in rabbits. This study aimed to further evaluate its safety and protective efficacy in cattle using different antigen ratios. After immunization, all vaccinated cattle had a normal rectal temperature and mental status without respiratory symptoms. CD4+, CD8+, and CD19+ cells significantly increased in immunized cattle and induced higher humoral and cellular immune responses, and the expression of key cytokines such as IL-4, IL-12, TNF-α, and IFN-γ can be promoted after vaccination. The 1.0 × 108 CFU of M. bovis HB150 and 1.0 × 106 TCID50 BoHV-1 gG-/tk- combined strain elicited the most antibodies while significantly increasing IgG and cellular immunity after challenge. In conclusion, the M. bovis HB150 and BoHV-1 gG-/tk- combined strain was clinically safe and protective in calves; the mix of 1.0 × 108 CFU of M. bovis HB150 and 1.0 × 106 TCID50 BoHV-1 gG-/tk- strain was most promising due to its low amount of shedding and highest humoral and cellular immune responses compared with others. This study introduces an M. bovis-BoHV-1 combined vaccine for application in the cattle industry.

Phase 3 immunogenicity and safety study of a tick-borne encephalitis vaccine in healthy Japanese participants 1 year of age and older.

BACKGROUND: Tick-borne encephalitis (TBE) virus infects the central nervous system and may lead to severe neurological complications or death. This study assessed immunogenicity, safety, and tolerability of TBE vaccine in Japanese participants 1 year of age and older. METHODS: This phase 3, multicenter, single-arm, open-label study was conducted in Japanese adult (≥ 16 years) and pediatric (1-< 16 years) populations. Participants received a single 0.5-mL (adult) or 0.25-mL (pediatric) dose of TBE vaccine at each of 3 visits. The primary endpoint was the proportion of participants who were seropositive (neutralization test [NT] titer ≥ 1:10) 4 weeks after Dose 3. Secondary and exploratory endpoints included NT seropositivity rates 4 weeks after Dose 2, immunoglobulin G (IgG) seropositivity 4 weeks after Doses 2 and 3, NT geometric mean titers (GMTs), IgG geometric mean concentrations (GMCs), and geometric mean fold rises. Primary safety endpoints were frequencies of local reactions, systemic events, adverse events (AEs), and serious AEs. RESULTS: Among 100 adult and 65 pediatric participants, 99.0 % and 100.0 % completed the study, respectively. NT seropositivity was achieved in 98.0 % adult and 100.0 % pediatric participants after Dose 3; seropositivity after Dose 2 was 93.0 % and 92.3 %, respectively. In both age groups, IgG seropositivity was ≥ 90.0 % and ≥ 96.0 % after Doses 2 and 3, respectively; GMTs and GMCs were highest 4 weeks after Dose 3. Reactogenicity events were generally mild to moderate in severity and short-lived. AEs were reported by 15.0 % (adult) and 43.1 % (pediatric) of participants. No life-threatening AEs, AEs leading to discontinuation, immediate AEs, related AEs, or deaths were reported. No serious AEs were considered related to TBE vaccine. CONCLUSIONS: TBE vaccine elicited robust immune responses in Japanese participants 1 year of age and older. The 3-dose regimen was safe and well tolerated, and findings were consistent with the known safety profile of this TBE vaccine. CLINICALTRIALS: gov: NCT04648241.

Immunogenicity, safety and duration of protection afforded by chikungunya virus vaccines undergoing human clinical trials.

Background. Chikungunya virus (CHIKV) causes chikungunya fever and has been responsible for major global epidemics of arthritic disease over the past two decades. Multiple CHIKV vaccine candidates are currently undergoing or have undergone human clinical trials, with one vaccine candidate receiving FDA approval. This scoping review was performed to evaluate the 'efficacy', 'safety' and 'duration of protection' provided by CHIKV vaccine candidates in human clinical trials.Methods. This scoping literature review addresses studies involving CHIKV vaccine clinical trials using available literature on the PubMed, Medline Embase, Cochrane Library and Clinicaltrial.gov databases published up to 25 August 2023. Covidence software was used to structure information and review the studies included in this article.Results. A total of 1138 studies were screened and, after removal of duplicate studies, 12 relevant studies were thoroughly reviewed to gather information. This review summarizs that all seven CHIKV vaccine candidates achieved over 90 % seroprotection against CHIKV after one or two doses. All vaccines were able to provide neutralizing antibody protection for at least 28 days.Conclusions. A variety of vaccine technologies have been used to develop CHIKV vaccine candidates. With one vaccine candidate having recently received FDA approval, it is likely that further CHIKV vaccines will be available commercially in the near future.

Post-vaccinal distemper-like disease in two dog litters with confirmed infection of vaccine virus strain.

Modified live canine distemper virus (CDV) vaccines are widely used and considered both safe and effective. Although there are occasional literature reports of suspected vaccine-induced disease, there are none where the vaccine strain has been identified in affected tissues. Here we describe two such cases in different litters. In litter A, five of ten puppies presented with fever, anorexia, vomiting, and diarrhea a few days post-vaccination. Four puppies died or were euthanized, and autopsy revealed atypical necrosis of the lymphoid tissue. In litter B, two of five puppies developed typical neurological signs some months post-vaccination and autopsy revealed encephalitis. In all cases, affected organs tested positive for CDV on immunohistochemistry, and CDV RNA extracted from the lesions confirmed the presence of vaccine strain. Since multiple puppies from each litter were affected, it cannot be excluded without further studies that some undiagnosed inherited immunodeficiency disorder may have been involved.

Progressive shingles in a toddler due to reactivation of Varicella Zoster vaccine virus four days after infection with SARS-CoV-2; a case report.

BACKGROUND: Herpes zoster (HZ) is the clinical syndrome associated with reactivation of latent varicella-zoster virus (VZV). Several factors have been implicated to promote VZV reactivation; these include immunosuppression, older age, mechanical trauma, physiologic stress, lymphopenia, and more recently, infection with severe acute respiratory syndrome coronavirus-2 (SARS- CoV-2). Recent reports suggest an increase in the number of HZ cases in the general population during the global COVID-19 pandemic. However, it is unknown what proportion of HZ during the pandemic is due to reactivation of wild-type or vaccine-strain VZV. CASE: Here we report the first known case of HZ concomitant with SARS-CoV2 infection in a 20-month-old female who was treated with a single dose of dexamethasone, due to reactivation of the vaccine-type strain of VZV after presenting with a worsening vesicular rash. CONCLUSION: In this case, we were able to show vaccine-strain VZV reactivation in the context of a mild acute symptomatic COVID-19 infection in a toddler. Being able to recognize HZ quickly and effectively in a pediatric patient can help stave off the significant morbidity and mortality associated with disease process.

Co-administration of chicken IL-2 alleviates clinical signs and replication of the ILTV chicken embryo origin vaccine by pre-activating natural killer cells and cytotoxic T lymphocytes.

IMPORTANCE: Chickens immunized with the infectious laryngotracheitis chicken embryo origin (CEO) vaccine (Medivac, PT Medion Farma Jaya) experience adverse reactions, hindering its safety and effective use in poultry flocks. To improve the effect of the vaccine, we sought to find a strategy to alleviate the respiratory reactions associated with the vaccine. Here, we confirmed that co-administering the CEO vaccine with chIL-2 by oral delivery led to significant alleviation of the vaccine reactions in chickens after immunization. Furthermore, we found that the co-administration of chIL-2 with the CEO vaccine reduced the clinical signs of the CEO vaccine while enhancing natural killer cells and cytotoxic T lymphocyte response to decrease viral loads in their tissues, particularly in the trachea and conjunctiva. Importantly, we demonstrated that the chIL-2 treatment can ameliorate the replication of the CEO vaccine without compromising its effectiveness. This study provides new insights into further applications of chIL-2 and a promising strategy for alleviating the adverse reaction of vaccines.

Retinal vein occlusion in the general population after COVID-19 vaccination and infection / Obstrucción venosa retiniana en la población general después de la vacunación y de la COVID-19

Introduction Retinal vein occlusion (RVO) is mostly a consequence of vascular risk factors (VRF). COVID-19 vaccines have been related to vascular and thrombotic events (VTE). Objective To assess the RVO incidence in the general population in our health area and the possible relation with COVID-19 infection and vaccination. Methods Demographic features, classic VRF, thrombophilia data, COVID-19 status, and Framingham risk score were collected prospectively. Results 472 consecutive patients studied over 13 years with RVO were included (Valdecilla Cohort). Classic VRFs were present in 90%, antiphospholipid syndrome in 12.3%, and genetic thrombophilia in 13.5%. Ninety-one percent of RVO patients were vaccinated and 6.8% suffered COVID-19 infection. In the cohort, no patient had a new RVO after vaccination or infection. In the general population, 20 subjects had RVO after receiving the vaccine (0.006%). Overall, 8 cases occurred in the first-month post-vaccination and 12 after 30 days. In the early and late groups, there are 3 and 4 patients respectively, with a low-intermediate risk Framingham score. Twenty-nine patients in the cohort suffered SARS-CoV-2 infection, twenty-seven of them had RVO before infection. Two patients with low-risk Framingham scores had RVO after infection, one of them early (<1 month). Conclusion Vaccination and COVID-19 might be involved in the development of RVO in some cases, mainly in patients without VRF, thrombophilia, or chronic inflammatory conditions and with a lower Framingham score, especially in the first month after vaccination or infection (AU)

Introducción La oclusión venosa retiniana (OVR) es principalmente una consecuencia de los factores de riesgo vascular (FRV). Las vacunas contra la COVID-19 se han relacionado con eventos vasculares y trombóticos (EVT). Objetivo Evaluar la incidencia de OVR en la población general de nuestra área de salud y su posible relación con la COVID-19 y la vacunación. Métodos Se recopilaron prospectivamente las características demográficas, FRV clásicos, datos sobre trombofilia, padecimiento de la COVID-19 y puntuación de riesgo de Framingham. Resultados Se incluyeron 472 pacientes consecutivos con OVR, estudiados durante 13 años (Cohorte Valdecilla). Los FRV clásicos estaban presentes en el 90%, el síndrome antifosfolípido en el 12,3% y la trombofilia genética en el 13,5% de los casos. El 91% de los pacientes con OVR recibieron la vacuna frente a la COVID-19 y el 6.8% sufrió la infección. En la cohorte, ningún paciente tuvo una nueva OVR después de la vacunación o de la infección. En la población general, 20 sujetos presentaron OVR después de recibir la vacuna (0,006%). En general, 8 casos ocurrieron en el primer mes después de la vacunación y 12 después de 30 días. En los grupos precoz y tardío, 3 y 4 pacientes respectivamente, presentaban una puntuación de Framingham de riesgo bajo o intermedio. Veintinueve pacientes de la cohorte sufrieron infección por SARS-CoV-2 y 27 de ellos tuvieron una OVR antes de ésta. Dos pacientes con puntuaciones de Framingham de bajo riesgo presentaron una OVR después de la infección, uno de ellos precozmente (<1 mes). Conclusiones La vacunación y la COVID-19 podrían estar involucradas en el desarrollo de OVR en algunos casos, principalmente en pacientes sin FRV, trombofilia o procesos inflamatorios crónicos y con una puntuación de Framingham más baja, especialmente en el primer mes después de la vacunación o de la infección (AU)

Influence of epidemiological and clinical factors in the reactogenicity to Comirnaty® vaccine in health care workers of a Spanish university teaching hospital (COVIVAC study) / Influencia de factores epidemiológicos y clínicos en la reactogenicidad a la vacuna Comirnaty® en trabajadores sanitarios de un hospital universitario español (estudio COVIVAC)

Introduction. 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). Material and 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. Conclusion. 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 (AU)

Introducción. Comirnaty® es una vacuna de ARNm contra el COVID-19 que se ha administrado a millones de personas desde finales de 2020. Nuestro objetivo fue estudiar los factores epidemiológicos y clínicos que influyen en la reactogenicidad y la limitación funcional asociadas tras las dos primeras dosis de la vacuna en trabajadores de la salud. Metodología. Estudio de cohorte prospectivo post-autorización para evaluar la seguridad y eficacia de la vacuna. Resultados. Los efectos secundarios locales fueron leves y se presentaron tanto con la primera como con la segunda dosis de Comirnaty. Los efectos secundarios sistémicos fueron más frecuentes después de la segunda dosis. No obstante, la infección previa por SARS-CoV-2 se asoció con efectos sistémicos tras la primera dosis de la vacuna (OR de 2 a 6). No se informaron efectos adversos graves. El análisis multivariante demostró que el grado de limitación funcional tras la primera dosis aumentó con la edad, el sexo femenino, contacto previo con COVID-19, la infección previa por SARS CoV-2 y el índice de comorbilidad de Charlson (ICC). Tras la segunda dosis, el grado de limitación funcional observado fue menor en aquellos con infección previa por SARS-CoV-2, y se asoció positivamente al grado de limitación funcional tras la primera dosis.Conclusión. Los efectos adversos sistémicos fueron más frecuentes después de la segunda dosis de Comirnaty. La infección previa por SARS-CoV-2 se asoció con efectos sistémicos después de la primera dosis. La edad, el sexo femenino, infección por COVID-19 previa, el aislamiento previo por contacto de COVID-19 y el ICC se mostraron como predictores independientes del grado de limitación funcional tras la 1ª dosis de Comirnaty®. Después de la 2.ª dosis, el grado de limitación funcional fue menor en los que previamente tenían infección por SARS-CoV-2 (AU)

[Enlightening from optimizing post-authorization safety monitoring system of SARS-CoV-2 vaccines in major economies worldwide].

Ongoing global pandemic of Coronavirus Disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has promoted the unprecedented rapid development and large-scale rolling out of different platform-based COVID-19 vaccines worldwide. How to effectively respond to the expected scale increasing adverse events after vaccination campaign of COVID-19 vaccines is a common problem faced by the world. A lot of countries and regions around the world have arranged in advance at different levels, optimizing the original vaccine safety monitoring system from the perspectives of strengthening the foundation and capabilities, promoting internal and external cooperation, upgrading methods, as well as improving transparency and public communication, which has ensured the good and efficient operation of the system and can provide reference for the construction of relevant fields in China.

Live IBD vaccine exacerbates disease and pathological effects of Asian lineage H9N2 LPAIV in chickens.

Avian influenza H9N2 is one of the most commonly circulating viruses in numerous Egyptian poultry farms. The Asian lineage H9N2 exhibits an immunosuppressive effect, and its pathogenicity is amplified when it co-infects with other pathogens, especially with the immunosuppressive infectious bursal disease virus (IBDV), resulting in increased mortality rates. Both vaccines and field infection can exacerbate the pathogenicity of H9N2, particularly in the bursa of Fabricius, causing more significant lymphoid depletion. To comprehend the impact of the IBD vaccine on the viral and pathogenic effect of H9N2 infection in specific pathogen-free chicks (SPF), the experiment was designed as four groups; group 1 served as the negative control, group 2 received (228E) IBD vaccine, group 3 was challenged with H9N2, and group-4 was vaccinated by the IBD vaccine then challenged with H9N2. The clinical signs, relative immune organs weights and histopathological lesion scores were recorded. The tracheal and cloacal H9N2 viral shedding were also measured. Group 4 exhibited a significant decrease (P ≤ 0.05) in the relative bursal weight and an increase in the bursal lesion score when compared with groups 1 and 3 at 4 and 8 days post-challenge (dpc). The tracheal lesion score of group-4 recorded a significant increase when compared with groups 1 and 3. The renal lesion score of group 4 achieved a significant increase when compared with 1 and 3 at 8 dpc. Also, group 4 recorded a significant increase in H9N2 shedding in comparison with groups 1 and 3. Consequently, our study concluded that routine vaccination with the IBD intermediate plus vaccine exacerbates the silent infection of H9N2 resulting in outbreaks.

Pivoting to protein: the immunogenicity and safety of protein-based NVX-CoV2373 as a heterologous booster for inactivated and viral vector COVID-19 vaccines.

INTRODUCTION: Approximately half of the 13.4 billion COVID-19 vaccine doses administered globally were inactivated or viral vector platforms. The harmonization and optimization of vaccine regimens has become a key focus of policymakers and health-care providers and presents an opportunity to reassess the continued use of pandemic-era vaccines. AREAS COVERED: Immunological evidence from studies of various homologous and heterologous regimens has been rapidly published; however, interpretation of these data is complicated by the many vaccine types and highly variable participant viral exposure and vaccination histories. Recent studies demonstrate that after primary series doses of inactivated (i.e. BBV152, and BBIBP-CorV), and viral vector (ChAdOx1 nCov-2019) vaccines, a heterologous boost with protein-based NVX-CoV2373 elicits more potent ancestral strain and omicron-specific antibody responses compared to homologous and heterologous inactivated and viral vector boosts. EXPERT OPINION: While mRNA vaccines likely yield similar performance to protein-based heterologous booster doses, the latter offers notable advantages to countries with high uptake of inactivated and viral vector vaccines in terms of transportation and storage logistics and can potentially appeal to vaccine hesitant individuals. Moving forward, vaccine-mediated protection in inactivated and viral vector recipients may be optimized with the use of a heterologous protein-based booster such as NVX-CoV2373. PIVOTING TO PROTEIN: The Immunogenicity and Safety of Protein-based NVX-CoV2373 as a Heterologous Booster for Inactivated and Viral Vector COVID-19 Vaccines. Inactivated or viral vector primary series following a booster dose with homologous or heterologous inactivated vaccines (i.e., BBV152, BBIBP-CorV), and homologous or heterologous viral vector vaccines (i.e., ChAd-Ox1 nCov-19) induces suboptimal immunogenicity compared to the enhanced immunogenicity of heterologous protein-based vaccine NVX-CoV2373.

The Evaluation of pediatric patients with suspected polyethylene glycol and polysorbate allergy before mRNA SARS-CoV2 vaccination

mRNA vaccines, particularly, have been associated with an increased risk of allergic reactions and rarely anaphylaxis. Although rare, vaccine reactions can cause significant anxiety and fear in the population, leading to indecision and vaccine refusal. This study aimed to retrospectively evaluate the role of polyethylene glycol (PEG) sensitivity in vaccination decision-making in pediatric patients at high risk of allergy or with suspected allergic reactions to the first dose of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) vaccine. Seventeen enrolled patients were found to have decreased readiness to receive the Coronavirus Disease 2019 (COVID-19) vaccine after developing hypersensitivity to multiple and/or injectable drugs. Skin testing was performed. A basophil activation test with PEG-2000 and 4000 was performed on three patients who were ineligible for skin prick tests. Nine patients with negative tests received the vaccine without complications. One patient had urticarial angioedema despite negative tests. Three patients with positive tests did not agree to desensitization with the mRNA vaccine, and one of them was vaccinated with the inactivated COVID-19 vaccine. Four patients recurred despite negative tests. The general recommendation for patients describing severe reactions to drugs, foods, and allergens, such as toxins that do not contain the adjuvants of the SARS-CoV-2 vaccines, is to be routinely vaccinated with safety precautions. Excipients such as PEG and polysorbate-80 used in COVID-19 vaccines could be potential allergens, but this hypothesis is unclear. The predictive values of these adjuvants for skin testing and in vitro testing are controversial. Further research is needed on the hypersensitivity reactions of adjuvants, the predictive values of skin tests, and etiopathogenesis (AU)

Estudio de reactogenicidad en las vacunas mRNA frente a la COVID-19 / Reactogenicity Study of mRNA Vaccines Against COVID-19

Objetivo: Comparar la reactogenicidad entre los tipos de vacuna RNAm Commirnaty® (Pfizer) y Spikevax® (Moderna) frente a la COVID-19 en población sanitaria.Métodos: Estudio de prevalencia de los efectos adversos a corto plazo y sus consecuencias tras la administración de la primera y segunda dosis en profesionales y estudiantes de una institución sanitaria. Se administró un cuestionario de síntomas y sus consecuencias a los 7 días de la vacunación. Se calculó la prevalencia e intervalo de confianza del 95% (IC95%). Las diferencias entre vacunas se cuantificaron mediante las odds ratio (OR) e IC95%.Resultados: Completaron el cuestionario 1924 y 1170 sanitarios (tasas de respuesta 62.2% y 39.1%) tras la primera y la segunda dosis, respectivamente, de la vacuna Commirnaty®, y 410 (56.0%) y 107 (15.0%), de Spikevax®. Después de la primera dosis de Comirnaty® un 67,4% presentó algún efecto adverso, y un 76,1% para Spikevax® (OR 1,5 IC95% 1,2-1,9). En general mujeres y jóvenes mostraron mayor reactogenicidad y diferencias entre vacunas. Las consecuencias de los efectos adversos fueron más frecuentes para Spikevax®. La reactogenicidad fue superior tras la segunda dosis que tras la primera, para las dos vacunas (Comirnaty® 67,4% vs. 75,6%; Spikevax® 76,1% vs. 87,9%).Conclusiones: La mayor reactogenicidad y sus consecuencias, para la primera y segunda dosis de la vacuna Spikevax® respecto a Comirnaty®, y de la segunda dosis respecto a la primera dosis de ambas vacunas, aporta conocimiento útil para la planificación de campañas de vacunación frente a la COVID-19 en el entorno sanitario. (AU)

Objective: To compare the reactogenicity between the types of mRNA Commirnaty® (Pfiz-er) and Spikevax® (Moderna) vaccines against COVID-19 in a healthcare population.Methods: Cross sectional study of short-term adverse effects and their consequences (sick leave, limitations of daily life, etc.) after the administration of the first and second doses of both vaccines in professionals and students of a health institution. A questionnaire on symptoms and their consequences was administered seven days after each vaccination dose. The prevalence and 95% confidence interval (95%CI) were calculated. Differences be-tween vaccines were quantified using the odds ratio (OR) and its 95%CI.Results: The questionnaire was completed by 1924 and 1170 healthcare providers (re-sponse rates 62.2% and 39.1%) after the first and second doses, respectively, of the Com-mirnaty® vaccine, and 410 (56.0%) and 107 (15.0%) of Spikevax®. After the first dose of Comirnaty®, 67.4% presented some adverse effect, and 76.1% for Spikevax® (OR 1.5 95%CI 1.2-1.9). In general, women and young people showed greater reactogenicity and differences between vaccines. Consequences of adverse effects were more frequent for Spikevax®. The reactogenicity was higher after the second than the first dose, for both vaccines (Comirnaty®: 67.4% vs. 75.6%; Spikevax®: 76.1% vs. 87.9%Conclusions: The greater reactogenicity and its consequences, for the first and second dose of the Spikevax® vaccine compared to Comirnaty®, and of the second dose com-pared to the first dose of both vaccines, provides useful knowledge for planning vaccination against COVID-19 campaigns in healthcare settings (AU)

SEROLOGIC RESPONSE AND ADVERSE EFFECTS OF RECOMBINANT CANINE DISTEMPER VACCINATION IN THREE AQUARIUM-HOUSED WALRUSES (ODOBENUS ROSMARUS).

Fatalities have been associated with phocine and canine distemper viruses in marine mammals, including pinnipeds. No data are available regarding distemper disease or vaccination in walruses. This study evaluates seroconversion and clinical adverse effects following administration of a canarypox-vectored recombinant distemper vaccination (two 1-ml doses, 3 wk apart) in three adult aquarium-housed walruses. Serum antibodies to distemper were measured using seroneutralization on blood samples collected under operant conditioning prior to and for 12 mon after vaccination or until titers were <32. All walruses seroconverted. Medium positive titers (64-128) were detected for 4 to 9.5 mon in two of three individuals. Interindividual variability was noted, with one individual displaying only low positive titers. Major swelling at the site of injection and lameness for a week following injection occurred in all three walruses. Further studies on dosing amount and interval are needed to make vaccine recommendations in this species.