Comparative efficacy of modified-live and inactivated vaccines in boosting responses to bovine respiratory syncytial virus, bovine parainfluenza virus Type 3, and bovine coronavirus following neonatal mucosal priming of beef calves.

Objective: This study compared clinical and immunological responses to coinfection challenge of beef calves mucosally primed and differentially boosted with commercial combination vaccines containing antigens against bovine coronavirus (BCoV), bovine parainfluenza virus Type 3 (BPIV3), and bovine respiratory syncytial virus (BRSV). Animals: Nineteen commercial beef heifers. Procedure: At birth, calves were mucosally (IN) primed with modified-live virus (MLV) vaccines, differentially boosted by injection of either combination MLV (IN-MLV) or inactivated virus (IN-KV) vaccines at a mean age of 44 d, and then challenged by coinfection with BCoV, BPIV3, and BRSV at weaning. Results: Both groups were similarly protected from clinical disease and had anamnestic neutralizing antibody responses to all 3 viruses. The IN-KV group shed more BCoV, and less BPIV3 and BRSV, than the IN-MLV group. Conclusion: These data indicated similar clinical and immunological protection between IN-MLV and IN-KV; however, shed of virus varied. Clinical relevance: Whereas boosting with KV or MLV appeared to have similar efficacy, viral shed differences may affect disease control.

Efficacité comparative des vaccins vivants modifiés et inactivés pour stimuler les réponses au virus respiratoire syncytial bovin, au virus parainfluenza bovin de type 3 et au coronavirus bovin après amorçage via la muqueuse de veaux de boucherie nouveau-nés. Objectif: Cette étude a comparé les réponses cliniques et immunologiques à une co-infection de veaux de boucherie amorcés par voie muqueuse et différentiellement stimulés avec des vaccins combinés commerciaux contenant des antigènes contre le coronavirus bovin (BCoV), le virus parainfluenza bovin de type 3 (BPIV3) et le virus respiratoire syncytial bovin (BRSV). Animaux: Dix-neuf génisses de boucherie commerciales. Procédure: À la naissance, les veaux ont été vaccinés au niveau des muqueuses (IN) avec des vaccins à virus vivants modifiés (MLV), stimulés de manière différentielle par l'injection de vaccins combinés MLV (IN-MLV) ou de virus inactivés (IN-KV) à un âge moyen de 44 jours. puis provoqué par une co-infection avec BCoV, BPIV3 et BRSV au sevrage. Résultats: Les deux groupes étaient protégés de la même manière contre la maladie clinique et présentaient des réponses anamnestiques en anticorps neutralisants contre les 3 virus. Le groupe IN-KV a excrété plus de BCoV et moins de BPIV3 et de BRSV que le groupe IN-MLV. Conclusion: Ces données indiquent une protection clinique et immunologique similaire entre IN-MLV et IN-KV; cependant, l'excrétion du virus variait. Pertinence clinique: Alors que le rappel avec KV ou MLV semble avoir une efficacité similaire, les différences d'excrétion virale peuvent affecter la limitation de la maladie.(Traduit par Dr Serge Messier).

Anti-SARS-CoV-2 antibody dynamics after primary vaccination with two-dose inactivated whole-virus vaccine, heterologous mRNA-1273 vaccine booster, and Omicron breakthrough infection in Indonesian health care workers.

BACKGROUND: Data on the dynamics and persistence of humoral immunity against SARS-CoV-2 after primary vaccination with two-dose inactivated vaccine (CoronaVac) are limited. This study evaluated the sequential effects of prior infection, heterologous boosting with mRNA-1273 (Moderna), and the occurrence of Omicron vaccine-breakthrough infection (VBI) thereafter. METHODS: We evaluated anti-spike IgG (Abbott) and neutralising (cPASS/GenScript) antibody (nAb) titers up to one year after mRNA-1273 boost in two-dose-CoronaVac-primed Indonesian healthcare workers (August 2021-August 2022). We used linear mixed modeling to estimate the rate of change in antibody levels, and logistic regression to examine associations between antibody levels and VBI. RESULTS: Of 138 participants, 52 (37.7%) had a prior infection and 78 (56.5%) received an mRNA-1273 booster. After two-dose CoronaVac, antibody titers had significantly declined within 180 days, irrespective of prior infection. After mRNA-1273 booster, anti-spike IgG (1.47% decline/day) and Omicron B.1.1.529/BA.2 nAbs declined between day 28-90, and IgG titers plateaued between day 90-360. During the BA.1/BA.2 wave (February-March 2022), 34.6% (27/78) of individuals experienced a VBI (median 181 days after mRNA-1273), although none developed severe illness. VBI was associated with low pre-VBI anti-spike IgG and B.1.1.529/BA.2 nAbs, which were restored post-VBI. CONCLUSIONS: mRNA-1273 booster after two-dose CoronaVac did not prevent BA.1/BA.2 VBI. Periodic vaccine boosters may be warranted against emerging SARS-CoV-2 variants.

Development of highly adaptable RT-PCR methods for identifying Delta and BA.1 variants in inactivated COVID-19 vaccines.

Background The emergence and rapid spread of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), poses a significant threat to human health and public safety. While next-generation sequencing (NGS) is capable of detecting and tracking new COVID-19 variants for disease diagnosis and prevention, its high cost and time-consuming nature limit its widespread use. In this study, our aim was to develop a highly adaptable and accurate RT-PCR method for identifying the Delta or BA.1 variants in inactivated COVID-19 vaccine. We devised three two-plex RT-PCR methods targeting specific mutation sites: S: Δ156-157, S: N211-, L212I, and S: Δ142-144, Y145D. The RT-PCR method targeting the S: Δ156-157 mutation site was able to distinguish the Delta variant from other COVID-19 virus strains, while the RT-PCR methods targeting the S: N211-, L212I or S: Δ142-144, Y145D mutation sites were able to distinguish the BA.1 variant from other COVID-19 virus strains. We separately validated these three two-plex RT-PCR methods, and the results demonstrated good linearity, repeatability, reproducibility, and specificity for each method. Moreover, all three methods can be applied in the production of SARS-CoV-2 variant inactivated vaccines, enabling the identification of Delta or BA.1 variants in virus cultures as well as in inactivated vaccine stocks. This study presents a systematic approach to identify COVID-19 variants using multiple RT-PCR methods. We successfully developed three two-plex RT-PCR methods that can identify Delta and BA.1 variants based on specific mutation sites, and we completed the validation of these three methods.

Comparison of long-term anti-RBD SARS-CoV-2 antibody response following different vaccination schemes in Tunisia.

AIM: The study aimed to compare long-term vaccine-induced humoral immunity following different vaccines regimens. METHODS: Anti-S-RBD total antibody levels were measured in blood samples of 167 participants nearly 6 months post-vaccination. Participants had received one; two or four doses of Pfizer vaccine or who received a third dose of mRNA vaccine (Pfizer) and primed with mRNA (Pfizer/Moderna), adenoviral (AstraZeneca/Jonson & Jonson) or inactivated (CoronaVac/Sinopharm) vaccine. RESULTS: Among all vaccination regimens, fourth dose of Pfizer achieved the highest S-RBD antibody titers. Nevertheless, the third dose of mRNA vaccine primed with adenoviral vaccine achieved the lowest titers of S-RBD antibody. Notably, the group that received a third dose of mRNA primed with two doses of mRNA vaccine exhibited higher S-RBD antibody compared to groups inoculated with a third dose of mRNA and primed with inactivated or adenovirus vaccine. CONCLUSION: Our data showed the superiority of three mRNA vaccinations compared to third heterologous vaccine (inactivated of adenoviral) including mRNA as booster in terms of humoral immunogenicity. Our findings supporting the use of additional booster shot from a more potent vaccine type such as mRNA vaccines. Nevertheless, due to the limited number of subjects, it is difficult to extrapolate the results of our study to the whole of Tunisian population. Future studies should investigate a larger cohort and other potential correlates of protection, such as cellular immunity and how it is affected by different vaccination schemes after long-term post-vaccination.

Safety of CoronaVac and ChAdOx1 vaccines against SARS-CoV-2 in patients with rheumatoid arthritis: data from the Brazilian multicentric study safer.

BACKGROUND: Patients with immune-mediated rheumatic diseases (IMRDs) have been prioritized for COVID-19 vaccination to mitigate the infection severity risks. Patients with rheumatoid arthritis (RA) are at a high risk of severe COVID-19 outcomes, especially those under immunosuppression or with associated comorbidities. However, few studies have assessed the safety of the COVID-19 vaccine in patients with RA. OBJECTIVE: To evaluate the safety of vaccines against SARS-CoV-2 in patients with RA. METHODS: This data are from the study "Safety and Efficacy on COVID-19 Vaccine in Rheumatic Diseases," a Brazilian multicentric prospective phase IV study to evaluate COVID-19 vaccine in IMRDs in Brazil. Adverse events (AEs) in patients with RA of all centers were assessed after two doses of ChAdOx1 (Oxford/AstraZeneca) or CoronaVac (Sinovac/Butantan). Stratification of postvaccination AEs was performed using a diary, filled out daily and returned at the end of 28 days for each dose. RESULTS: A total of 188 patients with RA were include, 90% female. CoronaVac was used in 109 patients and ChAdOx1 in 79. Only mild AEs were observed, mainly after the first dose. The most common AEs after the first dose were pain at the injection (46,7%), headache (39,4%), arthralgia (39,4%), myalgia (30,5%) and fatigue (26,6%), and ChAdOx1 had a higher frequency of pain at the injection (66% vs 32 %, p < 0.001) arthralgia (62% vs 22%, p < 0.001) and myalgia (45% vs 20%, p < 0.001) compared to CoronaVac. The more common AEs after the second dose were pain at the injection (37%), arthralgia (31%), myalgia (23%), headache (21%) and fatigue (18%). Arthralgia (41,4% vs 25%, p = 0.02) and pain at injection (51,4% vs 27%, p = 0.001) were more common with ChAdOx1. No serious AEs were related. With Regard to RA activity level, no significant difference was observed between the three time periods for both COVID-19 vaccines. CONCLUSION: In the comparison between the two immunizers in patients with RA, local reactions and musculoskeletal symptoms were more frequent with ChAdOx1 than with CoronaVac, especially after the first dose. In summary, the AE occurred mainly after the first dose, and were mild, like previous data from others immunizing agents in patients with rheumatoid arthritis. Vaccination did not worsen the degree of disease activity.

New vaccination approach using formalin-killed Streptococcus pyogenes vaccine on the liver of Oreochromis niloticus fingerlings.

Newly synthesized vaccines prepared from formalin-killed bacteria Streptococcus pyogenes were investigated in the current study to evaluate the effectiveness of the newly synthesized vaccine as well as their safety by injected intraperitoneal. The study involved several steps 1st step is the preparation of the vaccine followed by the 2nd step: Evaluate the effectiveness and vaccine safety against pathogenic S. pyogenes through 4 different groups including control (Group I). Group II (Bacterial, infected group), Group III (Vaccine), and the Last group was the challenged group after the vaccination (Vacc + Bac). Different Immunological and biochemical parameters were measured in addition to hematological and histopathological examinations. For example, oxidative/antioxidants, inflammatory biomarkers, fragmentation and cell damage, and finally the histopathological study. The current study showed an increase in all oxidative, inflammatory, and cell damage (DNA fragmentation assays), additionally markedly elevation in histopathological cell damage in the infected group (Group II) compared with the control group. The vaccine and challenged after vaccination group (vaccine + Bacteria), showed great improvement in oxidative biomarkers (LPO) and an increase in antioxidants biomarkers (GSH, SOD, GST, DPPH, ABTS, GR and GPx), Also the inflammation and histopathological examination. The newly synthesized vaccine improved the resistance of Oreochromis niloticus and can be used as a preventive therapy agent for pathogenic bacteria S. pyogenes.

Lot-to-lot consistency, immunogenicity and safety of a quadrivalent split virion inactivated influenza vaccine in healthy population aged 9-59 years: A randomized, double-blind, controlled, phase IV clinical trial.

OBJECTIVES: This study was to assess the lot-to-lot consistency, immunogenicity and safety of three manufacturing lots of a quadrivalent inactivated influenza vaccine (IIV4). METHODS: A randomized, double-blind, phase IV clinical trial was conducted in healthy children, adolescents and adults aged 9-59 years in Guizhou Province, China. Eligible participants were enrolled and randomized into three groups in a ratio of 1:1:1 to receive a single dose of one of three manufacturing lots of IIV4. Serum samples were collected before and 28 days after vaccination for hemagglutination inhibition (HI) antibody testing. Safety data were collected for up to 28 days after vaccination. The primary objective was to evaluate the lot-to-lot consistency of immune response as assessed by the geometric mean titer (GMT) of HI antibody at 28 days after vaccination. RESULTS: Between November 27, 2022 and December 18, 2022, 1260 eligible participants were enrolled, with similar participant demographics among groups. Immune responses after vaccination were comparable across groups, with the 95% confidence intervals (CIs) of GMT ratios for all 4 strains falling into the equivalence criterion of (0.67, 1.5). The seroconversion rates (SCRs) and seroprotection rates (SPRs) met the US Center or Biologics Evaluation and Research (CBER) criteria for all strains for each lot (lower limit of 95% CI of SCR ≥ 40% and SPR ≥ 70%). The incidences of solicited and unsolicited adverse reactions were similar among three groups, most of which (91.9%) were mild or moderate in severity. A total of 11 serious adverse events were reported during the study, and all were considered unrelated to vaccination. CONCLUSION: The three manufacturing lots of IIV4 demonstrated consistent immunogenicity. IIV4 can elicit satisfactory immune responses for all four strains and no safety concerns were identified. CLINICAL TRIAL REGISTRATION: Identifier No. NCT05512494.

Immunogenicity, clinical efficacy, and safety of the sinopharm (BBIBP-CorV) SARS-CoV-2 vaccine among people with multiple sclerosis receiving disease-modifying therapies: a prospective cohort study.

BACKGROUND: To investigate the safety (adverse events [AEs] and post-vaccination multiple sclerosis [MS] activity within 6 weeks), clinical efficacy (protection against coronavirus disease 2019 [COVID-19]), and vaccine-induced humoral immunogenicity (SARS-CoV-2 neutralizing antibody, anti-nucleocapsid IgG, and anti-spike IgG) of the Sinopharm (BBIBP-CorV) vaccine among people with MS (PwMS) receiving different disease-modifying therapies (DMTs). METHODS: This prospective cohort study was conducted between November 2021 and May 2022. PwMS were followed for six months after the 2nd dose of vaccination. Antibody responses were measured 2-16 weeks after the 2nd dose injection. Multivariate logistic regression was employed to assess the impact of each DMT on dichotomous antibody responses, adjusting for age, sex, MS phenotype, expanded disability status scale, disease duration, and vaccination-antibody titration interval. RESULTS: Among the 261 screened PwMS, 209 (aged 38.23 ± 9.73 years, female: 70.8%; relapsing-remitting MS: 80.4%) were included. The frequencies of experiencing non-serious AEs and post-vaccination MS activity were 66.0% and 4.8%, respectively. Breakthrough COVID-19 infection was observed in 14.8% of the PwMS. A subcohort of 125 PwMS was assessed for antibody responses. Positive neutralizing antibodies, anti-nucleocapsid IgG, and anti-spike IgG were detected in 36.8%, 35.2%, and 52.0% of the PwMS, respectively. Multivariate regression indicated a 96% (OR: 0.04 [95% CI: 0.00, 0.51], P = 0.013), 93% (OR: 0.07 [0.01, 0.64], P = 0.019), and 89% (OR: 0.11 [0.01, 0.96], P = 0.045) reduced odds of positive neutralizing antibody, anti-nucleocapsid IgG, and anti-spike IgG, respectively, among fingolimod-receivers. Additionally, anti-CD20s-receivers had 88% (OR: 0.12 [0.02, 0.85], P = 0.034) lower odds of being positive for anti-nucleocapsid IgG. CONCLUSIONS: BBIBP-CorV appeared to be well tolerated in PwMS, with promising clinical efficacy. However, a suboptimal humoral response was observed in PwMS receiving fingolimod and anti-CD20s. Future research should investigate the relationship between humoral responses and the frequency and severity of COVID-19 infection across various DMTs.

Efficacy, immunogenicity and safety of CoronaVac® in children and adolescents aged 6 months to 17 years: a multicenter, randomized, double-blind, placebo-controlled phase III clinical trial.

Safe and effective vaccines against COVID-19 for children and adolescents are needed. This international multicenter, randomized, double-blind, placebo-controlled, phase III clinical trial assessed the efficacy, immunogenicity, and safety of CoronaVac® in children and adolescents (NCT04992260). The study was carried out in Chile, South Africa, Malaysia, and the Philippines. The enrollment ran from September 10, 2021 to March 25, 2022. For efficacy assessment, the median follow-up duration from 14 days after the second dose was 169 days. A total of 11,349 subjects were enrolled. Two 3-µg injections of CoronaVac® or placebo were given 28 days apart. The primary endpoint was the efficacy of the CoronaVac®. The secondary endpoints were the immunogenicity and safety. The vaccine efficacy was 21.02% (95% CI: 1.65, 36.67). The level of neutralizing antibody in the vaccine group was significantly higher than that in the placebo group (GMT: 390.80 vs. 62.20, P <0.0001). Most adverse reactions were mild or moderate. All the severe adverse events were determined to be unrelated to the investigational products. In conclusion, in the Omicron-dominate period, a two-dose schedule of 3 µg CoronaVac® was found to be safe and immunogenic, and showed potential against symptomatic COVID-19 in healthy children and adolescents.

Heterologous booster vaccination enhances antibody responses to SARS-CoV-2 by improving Tfh function and increasing B-cell clonotype SHM frequency.

Heterologous prime-boost has broken the protective immune response bottleneck of the COVID-19 vaccines. however, the underlying mechanisms have not been fully elucidated. Here, we investigated antibody responses and explored the response of germinal center (GC) to priming with inactivated vaccines and boosting with heterologous adenoviral-vectored vaccines or homologous inactivated vaccines in mice. Antibody responses were dramatically enhanced by both boosting regimens. Heterologous immunization induced more robust GC activation, characterized by increased Tfh cell populations and enhanced helper function. Additionally, increased B-cell activation and antibody production were observed in a heterologous regimen. Libra-seq was used to compare the differences of S1-, S2- and NTD-specific B cells between homologous and heterologous vaccination, respectively. S2-specific CD19+ B cells presented increased somatic hypermutations (SHMs), which were mainly enriched in plasma cells. Moreover, a heterologous booster dose promoted the clonal expansion of B cells specific to S2 and NTD regions. In conclusion, the functional role of Tfh and B cells following SARS-CoV-2 heterologous vaccination may be important for modulating antibody responses. These findings provide new insights for the development of SARS-CoV-2 vaccines that induce more robust antibody response.

Integrated microbiome and metabolome analysis reveals that new insight into Radix pseudostellariae polysaccharide enhances PRRSV inactivated vaccine.

In this study, we investigated how Radix pseudostellariae polysaccharide (RPP) enhances the immune response of the inactivated porcine reproductive and respiratory syndrome virus (PRRSV) vaccine through interactions with the microbiome and metabolome. We pretreated sows with 10 mg/kg body weight of RPP via drinking water for 7 days prior to intramuscular injection of the PRRSV vaccine. This significantly increased the concentrations of PRRSV GP5 protein antibody, interleukin (IL)-2, IL-4, IL-10, and interferon (IFN)-γ. Oral administration of RPP also significantly improved the abundance of beneficial bacteria in the stool, such as Parabacteroides distasonis, Prevotella_copri, Eubacterium_sp., and Clostridium_sp._CAG:226, and decreased the levels of potentially pathogenic bacteria, such as Paraeggerthella and [Clostridium] innocuum, compared to the vaccine alone. These bacterial changes were confirmed using quantitative real-time polymerase chain reaction (Q-PCR). Moreover, RPP treatment significantly increased the blood concentrations of L-theanine, taurodeoxycholic acid (TDCA), and N-arachidonoyl proline, and decreased the levels of L-glutamine, oclacitinib, lipoxin C4, and leukotriene C5 in sows after immunization (p< 0.05). The concentrations of various blood metabolites were validated using sandwich enzyme-linked immunosorbent assay (ELISA), confirming the accuracy of the metabolomics data. Intriguingly, the integration of microbiome and metabolome analyses highlighted the significance of Prevotella_copri and TDCA. We consequently developed a mouse immunity model using GP5 protein and discovered that oral administration of RPP significantly enhanced the levels of GP5 protein antibodies, IL-2, IL-4, IL-10, and IFN-γ in mouse serum. It also increased the number of CD3+ and CD3+CD4+ cells in the spleen. Additionally, Prevotella_copri was administered into the large intestine via the anus for 7 days prior to the intramuscular injection of the PRRSV GP5 protein. The results demonstrated a significant increase in TDCA and GP5 antibody concentration in the mouse serum, indicating that RPP modulates Prevotella_copri to elevate its metabolite TDCA, thereby enhancing the GP5 antibody level. In conclusion, oral administration of 10 mg/kg RPP optimizes gut flora diversity and blood metabolites, particularly Prevotella_copri and TDCA, thereby improving the immune response to the inactivated PRRSV vaccine.

Adverse Effects Related to Paediatric Influenza Vaccination and Its Influence on Vaccination Acceptability. The FLUTETRA Study: A Survey Conducted in the Region of Murcia, Spain.

BACKGROUND: During the 2022-23 season, three autonomous communities recommended influenza vaccination for all children between 6 and 59 months. The objective is to evaluate the adverse effects associated with the administered influenza vaccines in the Region of Murcia, as well as their influence on the recommendation of the same to acquaintances or repetition in future seasons. MATERIAL AND METHODS: Cross-sectional descriptive study with an online questionnaire sent to the parents of vaccinated minors of 6-23 months of age receiving inactivated intramuscular vaccine (IIV) or 24-59 months of age receiving live-attenuated intranasal vaccine (LAIV). RESULTS: Among 4971 surveys received, the most common adverse effect for LAIV and IIV was runny nose (40.90%) and local pain (31.94%), respectively. Sixty percent of adverse effects lasted ≤ 1 day, and around 10% lasted ≥ 3 days. The interference of adverse effects with the minor's daily life was very infrequent (3.32%), as was the need for visiting the medical office (2.68%). Overall, 96.44% of parents would recommend influenza vaccination to friends and relatives after the experience. Only 3.56% would not recommend it, while 1.68% would not vaccinate their child against influenza again. The most frequently cited reason being adverse effects. CONCLUSIONS: Our study shows the safety of influenza vaccines. Despite the low impact of adverse effects, they influence some parents in their intention to continue vaccinating or recommending it to acquaintances, which remarks the need to reinforce the information given to parents so that this fact does not influence decision-making.

Effectiveness of influenza vaccine among the population in Chongqing, China, 2018-2022: A test negative design-based evaluation.

Influenza vaccination is the most cost-effective strategy for influenza prevention. Influenza vaccines have been found to be effective against symptomatic and medically attended outpatient influenza illnesses. However, there is currently a lack of data regarding the effectiveness of inactivated influenza vaccines in Chongqing, China. We conducted a prospective observational test-negative design study. Outpatient and emergency cases presenting with influenza-like illnesses (ILI) and available influenza reverse transcription polymerase chain reaction (RT-PCR) were selected and classified as cases (positive influenza RT-PCR) or controls (negative influenza RT-PCR). A total of 7,307 cases of influenza and 7,905 control subjects were included in this study. The overall adjusted influenza vaccine effectiveness (IVE) was 44.4% (95% confidence interval (CI): 32.5-54.2%). In the age groups of less than 6 years old, 6-18 years old, and 19-59 years old, the adjusted IVE were 32.2% (95% CI: 10.0-48.9%), 48.2% (95% CI: 30.6-61.4%), and 72.0% (95% CI: 43.6-86.1%). The adjusted IVE for H1N1, H3N2 and B (Victoria) were 71.1% (95% CI: 55.4-81.3%), 36.1% (95% CI: 14.6-52.2%) and 33.7% (95% CI: 14.6-48.5%). Influenza vaccination was effective in Chongqing from 2018 to 2022. Evaluating IVE in this area is feasible and should be conducted annually in the future.

Development of a high-performance liquid chromatography using rhodamine B hydrazide as the derivatization reagent for determination of ß propiolactone residues in inactivated COVID-19 vaccines.

ß-propiolactone (BPL) is an alkylating agent used for inactivation of biological samples such as vaccines. Due to its known carcinogenic properties, complete hydrolysis of BPL is essential, and the detection of trace amounts is crucial. In this study a novel High-Performance Liquid Chromatography-Ultraviolet (HPLC-UV) method was developed. Rhodamine B hydrazide (RBH) was synthesized and utilized as a derivatizing reagent to react with BPL. The reaction was optimized in a weak acidic solution, resulting in a high yield. The separation of the RBH-derivatized BPL was achieved on a C8 column and detected by a UV detector at a wavelength of 560 nm. The method's validation demonstrated a high linearity (r2 > 0.99) over a concentration range of 0.5-50 µg/mL, with detection and quantification limits of 0.17 µg/mL and 0.5 µg/mL, respectively. The average recovery of samples was 85.20 % with a relative standard deviation (RSD) of 1.75 %. This method was successfully applied for BPL residue analysis in inactivated COVID-19 vaccines. This novel derivatization method offers a promising solution for monitoring BPL residues in the vaccine production process for quality control purposes and compliance with regulatory standards.

Application prospects of the 2BS cell-adapted China fixed rabies virus vaccine strain 2aG4-B40.

BACKGROUND: Rabies is a fatal zoonotic disease whose pathogenesis has not been fully elucidated, and vaccination is the only effective method for protecting against rabies virus infection. Most inactivated vaccines are produced using Vero cells, which are African green monkey kidney cells, to achieve large-scale production. However, there is a potential carcinogenic risk due to nonhuman DNA contamination. Thus, replacing Vero cells with human diploid cells may be a safer strategy. In this study, we developed a novel 2BS cell-adapted rabies virus strain and analysed its sequence, virulence and immunogenicity to determine its application potential as a human diploid cell inactivated vaccine. METHODS AND RESULTS: The 2BS cell-adapted rabies virus strain 2aG4-B40 was established by passage for 40 generations and selection of plaques in 2BS cells. RNA sequence analysis revealed that mutations in 2BS cell-adapted strains were not located at key sites that regulate the production of neutralizing antibodies or virulence in the aG strain (GQ412744.1). The gradual increase in virulence (remaining above 7.0 logLD50/ml from the 40th to 55th generation) and antigen further indicated that these mutations may increase the affinity of the adapted strains for human diploid cells. Identification tests revealed that the 2BS cell-adapted virus strain was neutralized by anti-rabies serum, with a neutralization index of 19,952. PrEP and PEP vaccination and the NIH test further indicated that the vaccine prepared with the 2aG4-B40 strain had high neutralizing antibody levels (2.24 to 46.67 IU/ml), immunogenicity (protection index 270) and potency (average 11.6 IU/ml). CONCLUSIONS: In this study, a 2BS cell-adapted strain of the 2aG4 rabies virus was obtained by passage for 40 generations. The results of sequencing analysis and titre determination of the adapted strain showed that the mutations in the adaptive process are not located at key sequence regions of the virus, and these mutations may enhance the affinity of the adapted strain for human diploid cells. Moreover, vaccines made from the adapted strain 2aG4-B40 had high potency and immunogenicity and could be an ideal candidate rabies virus strain for inactivated vaccine preparation.

Immune reactivity of two biological models to vaccination with inactivated vaccine QazVac against coronavirus infection COVID-19.

INTRODUCTION: Specific prevention of a number of infectious diseases has been introduced into the vaccination schedule. The production of immunoprophylactic drugs, in order to establish standard properties, including safety and specific effectiveness, requires strict adherence to manufacturing regulations, and the reliability of the results obtained requires monitoring of these parameters. The specific effectiveness of vaccine preparations is standardized according to the indicators of stimulation of specific antibody response formed in the body of vaccinated model biological objects. OBJECTIVE: Determination of the immune reactivity of white mice to vaccination with the QazVac vaccine to establish the possibility of using them as a biological model in assessing the immunogenicity of the vaccine instead of Syrian hamsters. MATERIALS AND METHODS: The immune reactivity of model animals was assessed by the seroconversion rate, dynamics of antibody titers to the SARS-CoV-2 virus formed in the body after vaccination with the test vaccine. In the case of seropositivity of animals before administration of vaccine or placebo, the level of immune reactivity was calculated by the difference in antibody titers between control and vaccinated animals or by the difference in antibody titers before and after immunization. Specific antibodies were detected and their titer was determined using a neutralization reaction. RESULTS: The research results showed that the tested biological models had approximately the same immune reactivity to the administration of the QazVac vaccine, confirmed by the level and dynamics of antibody titers. When analyzing the fold increase in antibody titers in comparison to those of control animals, Syrian hamsters were more reactive compared to mice. But SPF white mice were standardized in their lack of the immune reactivity to SARS-CoV-2 virus before the immunization. CONCLUSION: The data obtained indicate that the immune reactivity of white mice to the administration of the QazVac vaccine in terms of the rate and dynamics of the formation of virus-neutralizing antibodies is approximately equivalent to the immune reactivity of Syrian hamsters. Before immunization with the vaccine, SPF white mice, in contrast to Syrian hamsters, do not have humoral immunity specific to the SARS-CoV-2 virus. The immune reactivity equivalent to that observed of Syrian hamsters and the absence of antibodies to the SARS-CoV-2 virus at a baseline indicate the superiority of the use of white mice in assessing the immunogenicity of vaccines against COVID-19 and/or obtaining specific factors of humoral immunity.

Evaluation of the efficacy of a new inactivated vaccine against Staphylococcus aureus, Echerchia coli and Mycoplasma bovis mastitis in cows.

Staphylococcus aureus, Escherichia coli and Mycoplasma bovis are the most commonly isolated mastitis pathogens. The aim of this study was to evaluate the efficacy of a new mixed vaccine against mastitis caused by  Staphylococcus aureus, Escherichia coli, and Mycoplasma bovis. For this purpose, a mixed inactivated vaccine was administered subcutaneously to 24 heifers as one dose (2 mL) on the 45th day before birth and the second dose 21 days later. In 9 heifers, 2 mL of PBS was administered as placebo instead of vaccine. Then, heifers were divided into 3 groups as 7 vaccinated and 3 unvaccinated animals. Staphylococcus aureus, Escherichia coli, and Mycoplasma bovis were administered to the groups through intramammary route. Three vaccinated heifers were considered the common control without bacteria in all groups. The parameters considered to assess the effect of vaccination were clinical findings, bacterial count in milk, somatic cell count, and antibody titers. Clinical signs were observed only in the unvaccinated placebo group. Bacteria count and somatic cell count in milk increased in vaccinated and unvaccinated heifers. However, this increase was less in vaccinated animals and gradually returned to the normal level. In the unvaccinated heifers, it was ever high. Serum antibody titers were measured before and after vaccination. Antibody titers were high in vaccinated heifers after vaccination and were negative in unvaccinated heifers. In conclusion, the mixed vaccine had beneficial effect against Staphylococcus aureus, Escherichia coli, and Mycoplasma bovis mastitis and stimulated the immune response of vaccinated heifers.

Antibody response to sequential vaccination with cell culture, recombinant, or egg-based influenza vaccines among U.S. adults.

The immune response to inactivated influenza vaccines (IIV) is influenced by multiple factors, including hemagglutinin content and egg-based manufacturing. Only two US-licensed vaccines are manufactured without egg passage: cell culture-based inactivated vaccine (ccIIV) and recombinant vaccine (RIV). We conducted a randomized open-label trial in central Wisconsin during the 2018-19 and 2019-20 seasons to compare immunogenicity of sequential vaccination. Participants 18-64 years old were randomized 1:1:1 to receive RIV, ccIIV or IIV in strata defined by number of influenza vaccine doses in the prior 3 years. They were revaccinated with the same product in year two. Paired serum samples were tested by hemagglutination inhibition against egg-adapted and cell-grown vaccine viruses. Serologic endpoints included geometric mean titer (GMT), mean fold rise, and percent seroconversion. There were 373 participants randomized and vaccinated in 2018-19; 332 were revaccinated in 2019-20. In 2018-19, RIV and ccIIV were not more immunogenic than IIV against A/H1N1. The post-vaccination GMT against the cell-grown 3C.2a A/H3N2 vaccine virus was higher for RIV vs IIV (p = .001) and RIV vs ccIIV (p = .001). The antibody response to influenza B viruses was similar across study arms. In 2019-20, GMT against the cell-grown 3C.3a A/H3N2 vaccine virus was higher for RIV vs IIV (p = .03) and for RIV vs ccIIV (p = .001). RIV revaccination generated significantly greater backboosting to the antigenically distinct 3C.2a A/H3N2 virus (2018-19 vaccine strain) compared to ccIIV or IIV. This study adds to the evidence that RIV elicits a superior immunologic response against A/H3N2 viruses compared to other licensed influenza vaccine products.

An inactivated SARS-CoV-2 vaccine based on a Vero cell culture-adapted high-titer virus confers cross-protection in small animals.

Rapidly waning immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) requires continued global access to affordable vaccines. Globally, inactivated SARS-CoV-2 vaccines have been widely used during the SARS-CoV-2 pandemic. In this proof-of-concept study we adapted an original-D614G SARS-CoV-2 virus to Vero cell culture as a strategy to enhance inactivated vaccine manufacturing productivity. A passage 60 (P60) virus showed enhanced fitness and 50-fold increased virus yield in a bioreactor compared to the original-D614G virus. It further remained susceptible to neutralization by plasma from SARS-CoV-2 vaccinated and convalescent individuals, suggesting exposure of relevant epitopes. Monovalent inactivated P60 and bivalent inactivated P60/omicron BA.1 vaccines induced neutralizing responses against original-D614G and BA.1 viruses in mice and hamsters, demonstrating that the P60 virus is a suitable vaccine antigen. Antibodies further cross-neutralized delta and BA.5 viruses. Importantly, the inactivated P60 vaccine protected hamsters against disease upon challenge with original-D614G or BA.1 virus, with minimal lung pathology and lower virus loads in the upper and lower airways. Antigenicity of the P60 virus was thus retained compared to the original virus despite the acquisition of cell culture adaptive mutations. Consequently, cell culture adaptation may be a useful approach to increase yields in inactivated vaccine antigen production.

Influence of bovine pestivirus heterogeneity on serological responses to 10 different commercial vaccine formulation.

Bovine Pestivirus typically involves one or more organ systems, with clinical manifestations ranging from mild to severe fatal systemic illness that lead to significant reproductive, productive, and economic losses. Vaccines face the challenge of addressing the significant variability of pestiviruses, which affects the interaction between viral antigens and the immune system's ability to provide protection. This study aimed to evaluate the serological responses against bovine viral diarrhea virus 1 (Pestivirus A) and Pestivirus B induced by 10 commercial vaccines, including one recombinant (vaccine E), two modified live (MLV multivalent, vaccine I, and MLV monovalent, vaccine J), and seven killed vaccines (KLV, vaccines A to H). Additionally, we evaluated the cross-reactivity between Pestivirus A and B from vaccines and HoBi-like pestivirus (Pestivirus H). In Phase 1, guinea pigs were used to screen for non-MLVs. They were divided into nine groups (n=6 each) and received two doses (⅕ of bovine dose) of eight different non-MLV on Days 0 and 21. Serum samples were collected on Days 0 and 30 for serological analyse. In Phase 2, Holstein × Gir heifers (n= 45) were divided into five groups, comprising 6-9 animals. They were vaccinated either once with MLVs or twice with the top non-MLVs screened in Phase 1. Serum samples were harvested on d0 (vaccination day) and d60 (60 days after the first dose) for MLV and non-MLV. Specific antibody titers were assessed virus neutralization (VN) and transformed in log2 for statistical analysis using PROC-MIXED. Significant effects were observed for vaccine groups, time points, and their interactions concerning neutralizing antibodies against Pestivirus A and B in both Guinea pigs and heifers. The Phase 1 study revealed serological responses against Pestivirus A exclusively in non-MLV D (85.33±13.49) and E (72.00±19.26). In the bovine study, the KLD vaccine D (72.00±15.10), recombinant vaccine E (90.66±25.85), and MLV I (170.66±28.22) resulted in an average of neutralizing antibodies against Pestivirus A that exceeded the protective threshold (≥ 60). However,individual analysis of heifers showed a higher frequency of animals presenting titers of Pestivirus A Ab surpassing 32 following vaccination with MLV I and J. None of the vaccine formulations in either study elicited a protective immune response against Pestivirus B or demonstrated cross-reactivity against Pestivirus H.