Vaccine最新文献

(1) Background: The administration of a live attenuated influenza vaccine (LAIV) has emerged as a viable option for preventing pediatric infections. The LAIV vaccine is available in China based on efficacy results. However, LAIV immunogenicity in children aged 3-17 years old in China has not yet to be studied and reported broadly. (2) Methods: This is a substudy investigating the immunogenicity and safety of the LAIV under a Phase 3, multicentre, randomized, double-blind, placebo-controlled trial. A total of 3000 participants were enrolled in a randomized, double-blind, placebo-controlled trial, split in half between vaccine and placebo, was conducted to evaluate a single LAIV dose in this age group. Hemagglutination inhibition (HI) antibody titers and incidence of adverse events were used to evaluate immunogenicity and safety, respectively. (3) Results: Although there was no significant difference in frequencies of all solicited or unsolicited AEs, nasal congestion, headache, and muscle pain were statistically significantly more frequent in vaccine recipients as compared to placebo Seroconversions and geometric mean fold increases in HI antibody titers against all strains were significantly higher in the vaccine group than in the placebo group. (4) Conclusions: The LAIV is safe and immunogenic in Chinese children and adolescents.

Mucosal secretory IgA (SIgA) produced by subepithelial plasma cells in the lamina propria is the major antigen-specific defense mechanism against mucosal infections. We investigated if a retinoic acid (RA)-containing adjuvant in parenteral immunization, can induce vaccine-specific SIgA in the jejunal lumen in a dose-dependent manner in neonatal pigs immunized with a Chlamydia hybrid antigen. To accurately quantify SIgA responses in mucosal secretions, an antigen-specific ELISA method with secondary detection of porcine secretory component rather than IgA was developed. RA facilitated a stronger (or faster) IgG, IgA, IgM and SIgA response in serum after primary immunization, and a more than 10-fold significantly increased level of vaccine-specific SIgA in jejunum at termination 2 weeks after the secondary boost, whereas IgA or SIgA responses in bronchoalveolar lavage (BAL) were not significantly increased after immunization with RA. Analyses of different isotype responses to vaccination and different sampling sites, revealed significant correlations between IgG and IgA responses in serum, and between IgG in serum and jejunum, while IgA in jejunum was neither correlated with IgA in serum nor with IgG in jejunum. This is indicative of IgG in jejunum being primarily a transudate from serum, while IgA is not. Jejunum SIgA correlated significantly with jejunum IgA and with both serum SIgA and IgA. Our results thus support the use of SC-specific reagents for mucosal SIgA responses, although IgA reagents to a lesser extent also reflects local antibodies. Although the IgA and SIgA levels in BAL were not significantly different with or without RA, we observed a significant correlation of vaccine-specific SIgA in jejunum and BAL, indicating a level of commonality in the regulation of mucosal antibodies in gut and respiratory system. In conclusion, an adjuvant with high concentration of RA was shown to increase the local intestinal mucosal antibody response after parenteral immunization in pigs.

In recent years, human mpox has made multiple resurges, prompting public health professionals to consider factors that lead to the increased risk for the reemergence of other orthopoxviruses. Due to the genetic similarity between orthopoxviruses, vaccinia vaccines used to prevent smallpox transmission are also indicated and have been used for mpox infection prevention and control. In this study, cross-reactive immunity for mpox was observed among individuals with self-reported history of smallpox vaccination. Differences in mean antigen response among individuals vaccinated in childhood and adulthood versus individuals vaccinated in childhood only were also observed, supporting the hypothesis that childhood smallpox vaccination may not be sufficient in providing long-lasting protection against multiple orthopoxviruses. These results provide insight on the durability of mpox immunogenic proteins and can be used to inform future studies to assess the benefits of reestablishing vaccinia vaccines as standard recommended immunizations, particularly where orthopoxviruses, such as mpox, are endemic.

The immune memory imprinted during an individual's initial influenza exposure (influenza imprinting) has long-lasting effects on the host's response to subsequent influenza infections and vaccinations. Here, we investigate how different influenza virus imprinting impacts the immune responses to subunit, inactivated virus, and protein-based nanoparticle vaccines in Balb/c mice. Our results indicated a phylogenetic distance-dependent effect of influenza imprinting on subunit hemagglutinin (HA) or formalin-inactivated (FI) virus vaccine immunizations. Aichi (H3N2, group 2) HA (HA3) or FI-Aichi vaccination in mice imprinted with closely related Phili (H3N2) triggered significant Aichi-specific HAI antibody and balanced HA3-specific Th1/Th2 antibody immune responses, resulting in robust protection against Aichi. In contrast, HA3 vaccination in PR8 (H1N1, group 1) imprinted mice (PR8-2HA3) induced Th2-leaning responses comparable to those observed in mice without prior influenza immune imprinting (PBS-2HA3). However, subsequent heterosubtypic infections and vaccinations eliminated such effects on antibody subtype profiles. Nonetheless, initial virus exposure established a long-lasting capacity to produce HAI antibody responses against the imprinting strains. Moreover, Phili imprinting followed by HA3/NP nanocluster vaccination protected mice from Aichi infections and induced enhanced cross-reactive immunity. Our study highlights the significance of considering an individual's influenza exposure history when designing and evaluating the effectiveness of influenza vaccines.

Influenza A viruses (IAV) of subtypes H1N1, H1N2, and H3N2 are endemic in US domestic swine populations and contribute to significant economic losses annually and pose a persistent pandemic threat. Adjuvanted, whole-inactivated virus (WIV) vaccines are the primary countermeasure to control IAV in swine. The compositions of these vaccines are matched for hemagglutinin (HA) strain and content, often ignoring the other IAV glycoprotein, the neuraminidase (NA). The IAV NA is immunogenic and antibodies targeting epitopes adjacent to the active site have been shown to inhibit the sialidase activity of NA thereby reducing virus replication and shedding. To assess the ability of neuraminidase inhibiting (NAI) antibodies induced from WIV administration to protect swine from challenge with IAV containing homologous and heterologous NA, we produced WIV composed of viruses with an irrelevant mismatched H9 HA but expressing NA proteins from two predominant clades (N2-2002A.2 and N22002B.2) currently circulating in US domestic swine populations. Pigs that received two doses of H9N2 WIV developed vaccine-specific neuraminidase inhibition antibodies and when challenged with a wild-type H3N2 virus containing homologous NA, displayed reduced virus shedding in the upper respiratory tract and decreased virus titers in the lung compared to unvaccinated controls. Pigs challenged with H3N2 containing a heterologous NA also had reduced virus titers in the nasal swab and BALF samples. Together these results show that NAI antibodies cross-protected across phylogenetic clades and reduced virus replication and shedding in swine.

Neuraminidase (NA)-specific antibodies contribute to immunity against influenza. While studies have demonstrated increased NA inhibiting (NAI) antibody titers after vaccination with egg-derived inactivated influenza vaccines (eIIV), the response to cell culture-derived (c) IIV has not been reported.

Methods: An immunogenicity sub-study was performed within a clinical trial comparing the effectiveness of egg, cell, and recombinant hemagglutinin (HA)-derived influenza vaccines during the 2018-2019 and 2019-2020 influenza seasons. NAI and neutralizing antibody titers against the A(H1N1)pdm09 and A(H3N2) components of the vaccines were measured in pre- and post-vaccination sera.

Results: Responses to the N1 component of eIIV and cIIV were different in both study years 1 and 2 whereas response rate and antibody titers to the N2 component of egg and cell culture-derived vaccines were similar. For example, 43.5 % of eIIV and no cIIV recipients had four-fold NAI titer increases in year 1. There was a weak positive correlation between responses to N1 and N2 for both vaccine types but no correlation between NAI and HA-specific neutralizing antibody responses. Recombinant HA vaccine that does not contain NA served as a specificity control; NAI antibody titers did not increase in recipients except in two individuals presumed to have subclinical infection.

Conclusion: Antibody responses to NA following vaccination with eIIV and cIIV were not the same; although the responses to the N1 and N2 components of eIIV were similar, there were fewer responders to N1 than N2 of cIIV. Studies to determine the impact of NA immunity on influenza vaccine effectiveness are warranted.

Background: Heart failure affects people of all ages and is a leading cause of death for both men and women in most racial and ethnic groups in the United States. Infections are common causes of hospitalizations in heart failure, with respiratory infections as the most frequent diagnosis. Vaccinations provide significant protection against preventable respiratory infections. Despite being an easily accessible intervention, prior studies suggest vaccines are underused in patients with heart failure.

Methods: An observational study of 5089 adults with heart failure was conducted using data from an integrated, multicenter, academic health system in Southern California from 2019 to 2022. Logistic regression models were used to determine the rates of influenza, pneumococcal, and COVID-19 vaccination among a population of patients with heart failure (heart failure preserved ejection fraction [HFpEF], heart failure mildly reduced ejection fraction [HFmrEF], and heart failure reduced ejection fraction [HFrEF], and identify whether heart failure phenotype is associated with vaccination status.

Results: Vaccination rates varied between influenza, pneumococcal, and COVID-19 vaccines. Of the three respiratory vaccines, 58.0 % of patients had received an influenza vaccine, 76.2 % had received a pneumococcal vaccine, and 83.3 % had received a COVID-19 vaccine. There were no sex-based differences by vaccination status. Differences were seen within age, race/ethnicity, insurance type, whether the patient was a member of an Accountable Care Organization (ACO), primary language, Social Vulnerability Index (SVI) score, clinician type, and number of comorbidities. Patients with HFpEF and HFmrEF had higher vaccination rates than HFrEF. In adjusted models, patients with HFrEF had lower odds of being vaccinated for influenza (aOR = 0.75, 95 % CI = 0.66-0.86), pneumococcal (aOR = 0.65, 95 % CI = 0.55-0.75), and COVID (aOR = 0.74, 95 % CI = 0.62-0.89) compared to patients with HFpEF.

Conclusions: Patients with HFrEF had the lowest levels of respiratory vaccination compared to other specified heart failure categories. Interventions are needed to increase vaccination education and offerings, especially to patients with HFrEF.

Introduction: The objective of our study was to estimate the influenza vaccine effectiveness for 2023/24 epidemic of co-circulating influenza A(H3N2) and B(Victoria) viruses in Beijing, China.

Methods: The surveillance-based study included all swabbed patients through influenza virological surveillance in Beijing, between October 2023 and March 2024. A Test-Negative Design(TND) was used to estimate influenza vaccine effectiveness(VE) against medically- attended laboratory-confirmed influenza in outpatient settings, also calculated the influenza vaccination rate(IVR). Cases were influenza-like illness (ILI) patients who tested positive for influenza, and controls were ILI who influenza negative patients.

Results: A total of 18,665 ILI patients were enrolled and swabbed. Among them, 6362(34.1 %) tested positive for influenza, major epidemic strain was A(H3N2) and B(Victoria). The overall IVR was 8.7 %, and the differences of IVR by gender, age, region, chronic conditions and month of onset were statistically significant(P<0.05). The adjusted VE against all influenza was moderate at 44.8 %, with the highest for B (Victoria) at 52.2 %, the highest for 19-59 age at 72.4 %, and the highest when vaccinated only in current season at 48.3 %.

Conclusion: Our study suggested the influenza vaccine has moderate effectiveness, with the best VE against B(Victoria), followed by A(H3N2) and A(H1N1)pdm09 in Beijing, 2023/24 season. Meanwhile, the influenza VE was relatively high in school-age children and the elderly. Consistent long-term studies are required in the future to evaluate the protect effect of influenza vaccine.