Vaccine Regimen Research Articles

Вплив перенесених паразитарних інфекцій під час вагітності на імунну систему плода (огляд літератури)

Transmission of infections during pregnancy is known to alter the development and functioning of the fetus immune system, resulting in an inadequate immune response to common childhood infections and immunizations. Although it is a developing and actively researched topic, maternal parasitic infections remain poorly understood. Millions of women of reproductive age are currently at risk of parasite infection, while many pregnant, chronically infected women are excluded from mass drug administration due in part to a lack of resources, as well as fear of unknown adverse fetal outcomes. infection, there is no clear mechanism for understanding how maternal infection reprograms offspring immunity. Purpose - to determine the currently studied mechanisms of the influence of parasitic infections transmitted during pregnancy on the immune system of the fetus and to describe the possible effects of these influence in the long term on the health of children. Conclusions. The study of maternal parasitic infections is a rapidly developing field. Although infant mortality rates are declining, areas with endemic parasites still have the highest infant mortality rates. As antiparasitic therapy is not always curable, there is a critical need to understand the effects of maternal infection on offspring immune development. Due to the increased risk of immune alteration due to maternal inflammation and reduced passive antibody transmission, maternal parasitic infections and their mechanism of adverse immunomodulation must be uncovered to improve vaccination regimens and reduce childhood morbidity in endemic regions. No conflict of interests was declared by the author.

Safety and immunogenicity of an Ad26.ZEBOV booster vaccine in Human Immunodeficiency Virus positive (HIV+) adults previously vaccinated with the Ad26.ZEBOV, MVA-BN-Filo vaccine regimen against Ebola: A single-arm, open-label Phase II clinical trial in Kenya and Uganda

BackgroundPeople living with HIV constitute an important part of the population in regions at risk of Ebola virus disease outbreaks. The two-dose Ad26.ZEBOV, MVA-BN-Filo Ebola vaccine regimen induces strong immune responses in HIV-positive (HIV+) adults but the durability of this response is unknown. It is also unclear whether this regimen can establish immune memory to enable an anamnestic response upon re-exposure to antigen. MethodsThis paper describes an open-label, phase 2 trial, conducted in Kenya and Uganda, of Ad26.ZEBOV booster vaccination in HIV+ participants who had previously received the Ad26.ZEBOV, MVA-BN-Filo primary regimen. HIV+ adults with well-controlled infection and on highly active antiretroviral therapy were enrolled, vaccinated with booster, and followed for 28 days. The primary objectives were to assess Ad26.ZEBOV booster safety and antibody responses against the Ebola virus glycoprotein using the Filovirus Animal Non-Clinical Group ELISA. ResultsThe Ad26.ZEBOV booster was well-tolerated in HIV+ adults with mostly mild to moderate symptoms. No major safety concerns or serious adverse events were reported. Four and a half years after the primary regimen, 24/26 (92 %) participants were still classified as responders, with a pre-booster antibody geometric mean concentration (GMC) of 726 ELISA units (EU)/mL (95 %CI 447–1179). Seven days after the booster, the GMC increased 54-fold to 38,965 EU/mL (95 %CI 23532–64522). Twenty-one days after the booster, the GMC increased 176-fold to 127,959 EU/mL (95 %CI 93872–174422). The responder rate at both post-booster time points was 100 %. ConclusionsThe Ad26.ZEBOV booster is safe and highly immunogenic in HIV+ adults with well-controlled infection. The Ad26.ZEBOV, MVA-BN-Filo regimen can generate long-term immune memory persisting for at least 4·5 years, resulting in a robust anamnestic response.Trial Registration: Pan African Clinical Trial Registry (PACTR202102747294430). Clinicaltrials.gov (NCT05064956).

The rLVS ΔcapB/iglABC vaccine provides potent protection in Fischer rats against inhalational tularemia caused by various virulent Francisella tularensis strains

ABSTRACT Francisella tularensis is one of the several biothreat agents for which a licensed vaccine is needed. To ensure vaccine protection is achieved across a range of virulent F. tularensis strains, we assembled and characterized a panel of F. tularensis isolates to be utilized as challenge strains. A promising tularemia vaccine candidate is rLVS ΔcapB/iglABC (rLVS), in which the vector is the LVS strain with a deletion in the capB gene and which additionally expresses a fusion protein comprising immunodominant epitopes of proteins IglA, IglB, and IglC. Fischer rats were immunized subcutaneously 1–3 times at 3-week intervals with rLVS at various doses. The rats were exposed to a high dose of aerosolized Type A strain Schu S4 (FRAN244), a Type B strain (FRAN255), or a tick derived Type A strain (FRAN254) and monitored for survival. All rLVS vaccination regimens including a single dose of 107 CFU rLVS provided 100% protection against both Type A strains. Against the Type B strain, two doses of 107 CFU rLVS provided 100% protection, and a single dose of 107 CFU provided 87.5% protection. In contrast, all unvaccinated rats succumbed to aerosol challenge with all of the F. tularensis strains. A robust Th1-biased antibody response was induced in all vaccinated rats against all F. tularensis strains. These results demonstrate that rLVS ΔcapB/iglABC provides potent protection against inhalational challenge with either Type A or Type B F. tularensis strains and should be considered for further analysis as a future tularemia vaccine.

Uptake of the COVID-2019 Vaccines Among College Students: Assessing Health Beliefs and Reasons for Vaccine Uptake

Background: College students are susceptible to airborne infectious diseases due to a communal living or learning environment. Adherence to vaccine regimens could safeguard population health in college communities. Aim: The aim of this study was to assess the relationship between COVID-19 vaccine uptake and health beliefs among university students using the Health Belief Model (HBM) constructs. The secondary objectives were to identify sources of health information on COVID-19 and reasons for vaccine uptake. Methods: A cross-sectional study was implemented among students at a university in the Northeastern region of the United States. The online survey assessed perceived susceptibility, severity, benefits, barriers, cues to action, and self-efficacy. Data analyses include qualitative, descriptive statistics, and logistic regression. Results: Of the 385 participants, 266 (69.1%) were within the age range of 20-29 years old. Three HBM constructs predicted vaccine uptake: (1) perceived benefits (aOR 5.02, 95% CI [2.86, 8.82], p = < 0.001), (2) perceived barriers (aOR 0.24, 95% CI [0.14, 0.42], p = <0.001), and (3) cues to action (aOR 4.36, 95% CI [1.92, 9.93], p = <0.001). The reason for vaccine uptake included protecting themselves and the community. A primary source of information varied in the study population. Conclusion: The study findings may inform college administ rators' decision-making to incorporate effective health promotion methods for vaccine uptake.

Vaccine development against tuberculosis before and after Covid-19.

Coronavirus disease (Covid-19) has not only shaped awareness of the impact of infectious diseases on global health. It has also provided instructive lessons for better prevention strategies against new and current infectious diseases of major importance. Tuberculosis (TB) is a major current health threat caused by Mycobacterium tuberculosis (Mtb) which has claimed more lives than any other pathogen over the last few centuries. Hence, better intervention measures, notably novel vaccines, are urgently needed to accomplish the goal of the World Health Organization to end TB by 2030. This article describes how the research and development of TB vaccines can benefit from recent developments in the Covid-19 vaccine pipeline from research to clinical development and outlines how the field of TB research can pursue its own approaches. It begins with a brief discussion of major vaccine platforms in general terms followed by a short description of the most widely applied Covid-19 vaccines. Next, different vaccination regimes and particular hurdles for TB vaccine research and development are described. This specifically considers the complex immune mechanisms underlying protection and pathology in TB which involve innate as well as acquired immune mechanisms and strongly depend on fine tuning the response. A brief description of the TB vaccine candidates that have entered clinical trials follows. Finally, it discusses how experiences from Covid-19 vaccine research, development, and rollout can and have been applied to the TB vaccine pipeline, emphasizing similarities and dissimilarities.

Safety and immunogenicity of the third and fourth doses of vaccine against SARS-CoV-2 following a 2-dose regimen of inactivated whole-virion SARS-CoV-2 vaccine

This study followed healthcare personnel (HCP) who had completed a primary series of CoronaVac and then received the third and fourth doses of COVID-19 vaccine. The primary objective was to determine the seroconversion rate of neutralizing antibodies against wild-type SARS-CoV-2 and VOCs at day 28 after the third dose of vaccine and day 28 after the fourth dose of vaccine. This prospective cohort study was conducted at Maharaj Nakorn Chiang Mai Hospital, a tertiary care hospital affiliated to Chiang Mai University from July 2021 to February 2022. Two hundred and eighty-three participants were assessed for eligibility; 142 had received AZD1222 and 141 BNT162b2 as the third dose. Seroconversion rates using a 30% inhibition cutoff value against wild-type SARS-CoV-2 were 57.2%, 98.6%, 97.8%, and 98.9% at points before and after the third dose, before and after the fourth dose, respectively among those receiving AZD1222 as the third dose. Frequencies were 31.9%, 99.3%, 98.9%, and 100% among those receiving BNT162b2 as the third dose, respectively. The seroconversion rates against B.1.1.529 [Omicron] were 76.1% and 90.2% (p-value 0.010) at 4 weeks after the third dose in those receiving AZD1222 and BNT162b2 as the third dose, respectively. After a booster with the mRNA vaccine, the seroconversion rates increased from 21.7 to 91.3% and from 30.4 to 91.3% in those receiving AZD1222 and BNT162b2 as the third dose, respectively. No serious safety concerns were found in this study. In conclusion, antibody responses waned over time regardless of the vaccine regimen. The booster dose of the vaccine elicited a humoral immune response against SARS-CoV-2 including SARS-CoV-2 variants of concern, including B.1.1.529 [Omicron], which was circulating during the study period. However, the results might not be extrapolated to other Omicron sublineages.

Prediction of long-term humoral response induced by the two-dose heterologous Ad26.ZEBOV, MVA-BN-Filo vaccine against Ebola

The persistence of the long-term immune response induced by the heterologous Ad26.ZEBOV, MVA-BN-Filo two-dose vaccination regimen against Ebola has been investigated in several clinical trials. Longitudinal data on IgG-binding antibody concentrations were analyzed from 487 participants enrolled in six Phase I and Phase II clinical trials conducted by the EBOVAC1 and EBOVAC2 consortia. A model based on ordinary differential equations describing the dynamics of antibodies and short- and long-lived antibody-secreting cells (ASCs) was used to model the humoral response from 7 days after the second vaccination to a follow-up period of 2 years. Using a population-based approach, we first assessed the robustness of the model, which was originally estimated based on Phase I data, against all data. Then we assessed the longevity of the humoral response and identified factors that influence these dynamics. We estimated a half-life of the long-lived ASC of at least 15 years and found an influence of geographic region, sex, and age on the humoral response dynamics, with longer antibody persistence in Europeans and women and higher production of antibodies in younger participants.

Japanese Encephalitis Vaccine Acceptance and Strategies for Travelers: Insights from a Scoping Review and Practitioners in Endemic Countries.

Japanese encephalitis (JE) remains the cause of vaccine-preventable encephalitis in individuals living in endemic areas and international travelers. Although rare, the disease's high fatality rate emphasizes the need for effective immunization. This review aims to provide updated data on the JE burden between 2017 and 2023, vaccine acceptance, and vaccine strategies for travelers. We prospectively identified studies, using MEDLINE and PubMed, published through 2023. JE incidence has decreased in local populations and remains low among travelers from non-endemic countries. The local JE risk cannot be utilized to determine traveler risk. Adult travelers naïve to JEV infection or immunization may be at potentially higher risk. The JE vaccine acceptance rates among international travelers visiting JE endemic areas range from 0.2% to 28.5%. The cost of the vaccine and low risk perception could be barriers to JE vaccination. For travelers, an accelerated two-dose regimen of inactivated Vero cell JE vaccine (JE-VC) or a single dosage of live attenuated JE vaccine (JE-LV) may be an option. In conclusion, the JE burden among residents and travelers is lower, but the risk is not negligible. Practitioners should prioritize sharing knowledge, increasing awareness, and promoting vaccinations and preventive measures to reduce tourists' risk of JE along their journey.

The fourth COVID-19 vaccine dose increased the neutralizing antibody response against the SARS-CoV-2 Omicron (B.1.1.529) variant in a diverse Brazilian population.

Most of the original immunization regimens against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were composed of two doses, followed by a subsequent third booster dose to control the Omicron variant and hence coronavirus disease 2019 (COVID-19). However, most data generated regarding the fourth dose were not based on the general population. Therefore, this study aimed to verify the effect of the fourth COVID-19 vaccine dose in a diverse Brazilian population. This retrospective observational study was conducted between May and September 2022. We gathered data on the vaccine regimens and COVID-19 serologic status from 266 healthy volunteers who received three or four vaccine doses, as well as COVID-19 diagnosis and viral genome sequencing from 457 patients with flu-like symptoms. In addition, we conducted immunoinformatic analysis to assess the conserved epitopes in the locally circulating viruses. We showed that the fourth dose did not increase the serum levels of antiviral antibodies, as measured by enzyme-linked immunosorbent assay. However, it significantly increased neutralizing antibody (NAb) titers against the Omicron variant. All viral sequences generated in this study were Omicron subvariants, mainly B.A.5.1. Notably, most NAb epitopes present in the wild-type SARS-CoV-2 were not detected among the circulating Omicron subvariants. None of the volunteers who received the third or fourth doses presented COVID-19 for at least 1 year before the study period. Altogether, these results indicate that the fourth vaccine dose increases the serum levels of NAbs that recognize highly conserved epitopes in Omicron subvariants.IMPORTANCESeveral additional COVID-19 vaccine doses were administered in the Brazilian population to prevent the disease caused by the B.1.1.529 (Omicron) variant. The efficacy of a third dose as a booster is already well described. However, it is important to clarify the humoral immune response gain induced by a fourth dose. In this study, we evaluate the effect of the fourth COVID-19 vaccine dose in a diverse Brazilian population, considering a real-life context. Our study reveals that the fourth dose of the COVID-19 vaccine increased the neutralizing antibody response against SARS-CoV-2 Omicron and significantly contributed in the reduction of the disease caused by this variant.

Dynamics and durability of HIV-1 neutralization are determined by viral replication

Human immunodeficiency virus type 1 (HIV-1)-neutralizing antibodies (nAbs) that prevent infection are the main goal of HIV vaccine discovery. But as no nAb-eliciting vaccines are yet available, only data from HIV-1 neutralizers—persons with HIV-1 who naturally develop broad and potent nAbs—can inform about the dynamics and durability of nAb responses in humans, knowledge which is crucial for the design of future HIV-1 vaccine regimens. To address this, we assessed HIV-1-neutralizing immunoglobulin G (IgG) from 2,354 persons with HIV-1 on or off antiretroviral therapy (ART). Infection with non-clade B viruses, CD4+ T cell counts <200 µl−1, being off ART and a longer time off ART were independent predictors of a more potent and broad neutralization. In longitudinal analyses, we found nAb half-lives of 9.3 and 16.9 years in individuals with no- or low-level viremia, respectively, and 4.0 years in persons who newly initiated ART. Finally, in a potent HIV-1 neutralizer, we identified lower fractions of serum nAbs and of nAb-encoding memory B cells after ART initiation, suggesting that a decreasing neutralizing serum activity after antigen withdrawal is due to lower levels of nAbs. These results collectively show that HIV-1-neutralizing responses can persist for several years, even at low antigen levels, suggesting that an HIV-1 vaccine may elicit a durable nAb response.

COVID-19 infection and efficacy of vaccination in patients with rheumatic diseases during Omicron outbreak in South Korea: a prospective cohort study

ObjectivesThis study aims to investigate COVID-19 epidemiological data in patients with autoimmune inflammatory rheumatic diseases (AIRDs) during Omicron wave and to identify clinical factors associated with infection, including COVID-19 vaccination.MethodsThis...

Pneumococcal Vaccination Recommendation and Completion Rates Among Patients With Inflammatory Bowel Disease and Barriers to Vaccination.

Guidelines for inflammatory bowel disease (IBD) patients receiving immunosuppression encouraged both the pneumococcal polysaccharide vaccine (PPSV23) and the pneumococcal conjugate vaccine (PCV13). We aimed to evaluate which pneumococcal vaccines are recommended and administered, and to understand provider and IBD patient knowledge regarding pneumococcal vaccinations. We performed a retrospective, cross-sectional analysis of 357 adult IBD patients on immunosuppression in our health care system. Patient demographics and clinical characteristics were collected. The primary outcome was rate of documented vaccinations recommended by providers; the secondary outcome was rate of receipt of the vaccines. We identified factors associated with receipt of any pneumococcal vaccine through multivariable logistic regression. We also performed provider and IBD patient surveys to understand provider and patient knowledge regarding pneumococcal vaccines. We used χ 2 and Fisher exact tests to assess survey responses. Fifty seven percent of IBD patients had any pneumococcal vaccination recommended and 35% had recommendations for both PPSV23 and PCV13. Forty percent received any pneumococcal vaccine and 18% received both vaccines. In multivariable analyses, increasing age (adjusted odds ratio: 1.03, 95% CI: 1.01-1.05) was associated with receipt of any pneumococcal vaccine, after adjusting for gender, race, insurance, disease activity, and time seen in our gastroenterology clinics. In the survey study, on average, 59% of providers correctly answered questions regarding pneumococcal vaccination indications. In our health care system, while recommendation for any pneumococcal vaccination was >50%, receipt of both PPSV23 and PCV13 was low. Simplified vaccine regimens (ie, PCV20) will likely improve vaccination rates.

Effect of Secukinumab and Tumor Necrosis Factor Inhibitors on Humoral Response to BNT162b2 mRNA Vaccine in Patients With Spondyloarthritis Compared to Immunocompetent Controls.

To assess the humoral response to the BNT162b2 mRNA vaccine among patients with spondyloarthritis (SpA) receiving secukinumab (SEC) compared to those receiving tumor necrosis factor inhibitors (TNFi) and immunocompetent controls. Consecutive patients with psoriatic arthritis or axial SpA receiving SEC (n = 37) or TNFi (monotherapy, n = 109; + methotrexate [MTX], n = 16), immunocompetent controls (n = 122), and patients with rheumatoid arthritis (RA) receiving TNFi therapy (controls, n = 50) were vaccinated with 2 or 3 doses of the BNT162b2 vaccine. We evaluated humoral response, adverse events, and disease activity, and monitored for breakthrough coronavirus disease 2019 (COVID-19) postvaccination. The 2-dose vaccine regimen induced a comparable seropositive response in all study groups. S1/S2 antibody titers (in binding antibody units/mL; mean [SD]) were higher in the SEC group vs the TNFi + MTX-SpA and TNFi-RA groups (192.5 [68.4] vs 104.6 [46.9], P < 0.001, and 143.1 [81.9], P = 0.004). After 6 months, 96.3%, 96.6%, and 80.9% of the SEC, immunocompetent, and TNFi monotherapy-SpA groups (P = 0.10), respectively; 66.7% of the TNFi + MTX-SpA group (P = 0.03); and 63% of the TNFi-RA group (P = 0.004) remained seropositive. S1/S2 antibody titer decline was steeper in the TNFi groups than the SEC group. After the third dose, 100% of the SpA and immunocompetent and 88.9% of the TNFi-RA (P = 0.25) groups were seropositive. Rate of breakthrough COVID-19 infection was higher in the TNFi groups than in the SEC group (36-37.5% vs 10.8%). No significant between-group differences were observed for postvaccination disease activity and adverse events. SEC did not interfere with the immunogenic response to BNT162b2 vaccine in patients with SpA; however, TNFi therapy was associated with lower S1/S2-antibody titers, faster decline, and higher rate of breakthrough infections.

Whole Genomic Constellation of Avian Reovirus Strains Isolated from Broilers with Arthritis in North Carolina, USA.

Avian reovirus (ARV) is an emerging pathogen which causes significant economic challenges to the chicken and turkey industry in the USA and globally, yet the molecular characterization of most ARV strains is restricted to a single particular gene, the sigma C gene. The genome of arthrogenic reovirus field isolates (R18-37308 and R18-38167), isolated from broiler chickens in North Carolina (NC), USA in 2018, was sequenced using long-read next-generation sequencing (NGS). The isolates were genotyped based on the amino acid sequence of sigma C (σC) followed by phylogenetic and amino acid analyses of the other 11 genomically encoded proteins for whole genomic constellation and genetic variation detection. The genomic length of the NC field strains was 23,494 bp, with 10 dsRNA segments ranging from 3959 bp (L1) to 1192 bp (S4), and the 5' and 3' untranslated regions (UTRs) of all the segments were found to be conserved. R18-37308 and R18-38167 were found to belong to genotype (G) VI based on the σC analysis and showed nucleotide and amino acid sequence identity ranging from 84.91-98.47% and 83.43-98.46%, respectively, with G VI strains. Phylogenetic analyses of individual genes of the NC strains did not define a single common ancestor among the available completely sequenced ARV strains. Nevertheless, most sequences supported the Chinese strain LY383 as a probable ancestor of these isolates. Moreover, amino acid analysis revealed multiple amino acid substitution events along the entirety of the genes, some of which were unique to each strain, which suggests significant divergence owing to the accumulation of point mutations. All genes from R18-37308 and R18-38167 were found to be clustered within genotypic clusters that included only ARVs of chicken origin, which negates the possibility of genetic pooling or host variation. Collectively, this study revealed sequence divergence between the NC field strains and reference ARV strains, including the currently used vaccine strains could help updating the vaccination regime through the inclusion of these highly divergent circulating indigenous field isolates.

Vaccination with an HIV T-Cell Immunogen (HTI) Using DNA Primes Followed by a ChAdOx1-MVA Boost Is Immunogenic in Gut Microbiota-Depleted Mice despite Low IL-22 Serum Levels.

Despite the important role of gut microbiota in the maturation of the immune system, little is known about its impact on the development of T-cell responses to vaccination. Here, we immunized C57BL/6 mice with a prime-boost regimen using DNA plasmid, the Chimpanzee Adenovirus, and the modified Vaccinia Ankara virus expressing a candidate HIV T-cell immunogen and compared the T-cell responses between individuals with an intact or antibiotic-depleted microbiota. Overall, the depletion of the gut microbiota did not result in significant differences in the magnitude or breadth of the immunogen-specific IFNγ T-cell response after vaccination. However, we observed marked changes in the serum levels of four cytokines after vaccinating microbiota-depleted animals, particularly a significant reduction in IL-22 levels. Interestingly, the level of IL-22 in serum correlated with the abundance of Roseburia in the large intestine of mice in the mock and vaccinated groups with intact microbiota. This short-chain fatty acid (SCFA)-producing bacterium was significantly reduced in the vaccinated, microbiota-depleted group. Therefore, our results indicate that, although microbiota depletion reduces serum levels of IL-22, the powerful vaccine regime used could have overcome the impact of microbiota depletion on IFNγ-producing T-cell responses.

Perinatal Outcomes at Birth in Women Infected and Non-Infected with SARS-CoV-2: A Retrospective Study

Background: Coronavirus disease 2019 (COVID-19) was declared as a pandemic and public health emergency on 11 March 2020 by the World Health Organization. Different clinical trials on the efficacy of mRNA vaccination have excluded pregnant women, leading to a lack of empirical evidence on the efficacy of the vaccine in this population. The aim of the study was to examine the association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection at birth and adverse perinatal outcomes in infected and non-infected women from a university hospital in Spain. Methods: The data were obtained from electronic health records from 1 March 2020 to 28 February 2022. A bivariate descriptive analysis was performed, comparing women with and without confirmed SARS-CoV-2 infection during pregnancy using the chi-square test. A multivariate logistic regression was complementarily conducted to determine whether SARS-CoV-2 infection increases the risk of adverse obstetric and perinatal outcomes. Results: A total of 2676 women were divided into two groups: non-infected with SARS-CoV-2 (n = 2624) and infected with SARS-CoV-2 (n = 52). Infected women were primarily multiparous (p &lt; 0.03) and had received an incomplete vaccination regimen (p &lt; 0.001). A greater incidence of premature rupture of membranes (p &lt; 0.04) was observed among the non-infected women. Pertaining to perinatal outcomes, there was a notable rise in NICU admissions (p &lt; 0.014), coupled with an extended duration of stay (p &lt; 0.04), for neonates born to infected mothers in comparison to their non-infected counterparts. Conclusion: Although SARS-CoV-2 infection may pose significant risks to pregnant women and their infants, adverse obstetrical/puerperal outcomes do not significantly differ between women infected and non-infected to SARS-CoV-2 in our study. NICU admissions were higher for neonates born to infected mothers. Additionally, coronavirus disease 2019 vaccination during pregnancy is not associated with severe adverse perinatal outcomes.

Effectiveness of the second COVID-19 booster against Omicron: a large-scale cohort study in Chile

In light of the ongoing COVID-19 pandemic and the emergence of new SARS-CoV-2 variants, understanding the effectiveness of various booster vaccination regimens is pivotal. In Chile, using a prospective national cohort of 3.75 million individuals aged 20 or older, we evaluate the effectiveness against COVID-19-related intensive care unit (ICU) admissions and death of mRNA-based second vaccine boosters for four different three-dose background regimes: BNT162b2 primary series followed by a homologous booster, and CoronaVac primary series followed by an mRNA booster, a homologous booster, and a ChAdOx-1 booster. We estimate the vaccine effectiveness weekly from February 14 to August 15, 2022, by determining hazard ratios of immunization over non-vaccination, accounting for relevant confounders. The overall adjusted effectiveness of a second mRNA booster shot is 88.2% (95%CI, 86.2–89.9) against ICU admissions and 90.5% (95%CI 89.4–91.4) against death. Vaccine effectiveness shows a mild decrease for all regimens and outcomes, probably linked to the introduction of BA.4 and BA.5 Omicron sub-lineages and the waning of immunity. Based on our findings, individuals might not need additional boosters for at least 6 months after receiving a second mRNA booster shot in this setting.

Inference of transmission dynamics and retrospective forecast of invasive meningococcal disease.

The pathogenic bacteria Neisseria meningitidis, which causes invasive meningococcal disease (IMD), predominantly colonizes humans asymptomatically; however, invasive disease occurs in a small proportion of the population. Here, we explore the seasonality of IMD and develop and validate a suite of models for simulating and forecasting disease outcomes in the United States. We combine the models into multi-model ensembles (MME) based on the past performance of the individual models, as well as a naive equally weighted aggregation, and compare the retrospective forecast performance over a six-month forecast horizon. Deployment of the complete vaccination regimen, introduced in 2011, coincided with a change in the periodicity of IMD, suggesting altered transmission dynamics. We found that a model forced with the period obtained by local power wavelet decomposition best fit and forecast observations. In addition, the MME performed the best across the entire study period. Finally, our study included US-level data until 2022, allowing study of a possible IMD rebound after relaxation of non-pharmaceutical interventions imposed in response to the COVID-19 pandemic; however, no evidence of a rebound was found. Our findings demonstrate the ability of process-based models to retrospectively forecast IMD and provide a first analysis of the seasonality of IMD before and after the complete vaccination regimen.

A novel simian adenovirus-vectored COVID-19 vaccine elicits effective mucosal and systemic immunity in mice by intranasal and intramuscular vaccination regimens.

The failure of COVID-19 vaccines to prevent SARS-CoV-2 infection and transmission, a possibly critical reason was the lack of protective mucosal immunity in the respiratory tract. Here, we evaluated the effects of mucosal and systemic immunity from a novel simian adenovirus-vectored COVID-19 vaccine (Sad23L-nCoV-S) in mice in comparison with Ad5-nCoV-S by intranasal (IN) drip and intramuscular (IM) injection vaccinations. As good as the well-known Ad5-nCoV-S vaccine, a single-dose IN inoculation of 1 × 109 PFU Sad23L-nCoV-S vaccine induced a similar level of IgG S-binding antibody (S-BAb) and neutralizing antibody (NAb) and higher IgA in serum, while IN route raised significantly higher IgG and IgA S-BAb and NAb in bronchoalveolar lavage (BAL), and specific IFN-γ secreting T-cell response in lung compared with IM route, but lower T-cell response in spleen. By prime-boost vaccination regimens with different combinations of IN and IM inoculations of Sad23L-nCoV-S vaccine, the IN-involved vaccination stimulated higher protective mucosal or local immunity in BAL and lung, while the IM-involved immunization induced higher systemic immunity in serum and spleen. A long-term sustained mucosal and systemic NAb and T- cell immunity to SARS-CoV-2 was maintained at high level over 32 weeks by prime-boost vaccination regimens with IN and IM routes. In conclusion, priming or boosting immunization with IN inoculation of Sad23L-nCoV-S vaccine could induce effective mucosal immunity and in combination of IM route could additionally achieve systemic immunity, which provided an important reference for vaccination regimens against respiratory virus infection. IMPORTANCE The essential goal of vaccination is to generate potent and long-term protection against diseases. Several factors including vaccine vector, delivery route, and boosting regimen influence the outcome of prime-boost immunization approaches. The immunization regimens by constructing a novel simian adenovirus-vectored COVID-19 vaccine and employing combination of intranasal and intramuscular inoculations could elicit mucosal neutralizing antibodies against five mutant strains in the respiratory tract and strong systemic immunity. Immune protection could last for more than 32 weeks. Vectored vaccine construction and immunization regimens have positively impacted respiratory disease prevention.

Inactivated SARS-CoV-2 Vaccine Booster Against Omicron Infection Among Quarantined Close Contacts.

Assessment of additional protection of a booster dose with an inactivated SARS-CoV-2 vaccine is key to developing vaccination strategies for billions of people worldwide who have received the primary 2-dose regimen. To estimate the relative effectiveness of a booster dose of an inactivated SARS-CoV-2 vaccine against Omicron infection. This cohort study was conducted among primary close contacts without previous SARS-CoV-2 infection identified in Shenzhen, China, between February and October 2022. Multiple strict nucleic acid testing and symptom surveillance for SARS-CoV-2 infection were regularly conducted during the 7-day centralized plus 7-day home-based quarantine. A booster with an inactivated SARS-CoV-2 vaccine vs no booster after receipt of the primary 2-dose inactivated SARS-CoV-2 vaccine regimen. The primary outcomes were overall, symptomatic, and asymptomatic infections. Secondary outcomes were length of incubation and level of cycle threshold values. All the outcomes were assessed during the quarantine period. Among 119 438 eligible participants (mean [SD] age, 37.6 [12.0] years; 66 201 men [55.4%]), 86 251 (72.2%) received a booster dose of an inactivated SARS-CoV-2 vaccine and 33 187 (27.8%) did not. A total of 671 cases infected with Omicron BA.2 were confirmed (464 symptomatic and 207 asymptomatic), and no severe infection or death events were observed. At a median (IQR) duration of 111 (75 to 134) days after booster vaccination, the relative effectiveness of a booster was 32.2% (95% CI, 11.3% to 48.2%) for overall infection, 23.8% (95% CI, -8.2% to 46.4%) for symptomatic infection, and 43.3% (95% CI, 12.3% to 63.3%) for asymptomatic infection. The effectiveness against overall infection changed nonlinearly over time following booster vaccination: 44.9% (95% CI, 4.9% to 68.1%) within 60 days, 50.4% (95% CI, 23.7% to 67.7%) at 61 to 120 days, 29.1% (95% CI, -4.8% to 52.1%) at 121 to 180 days, and 19.4% (95% CI, -14.4% to 43.2%) after 180 days (nonlinear P = .03). The effectiveness did not vary significantly according to the interval between booster vaccination and completion of primary vaccination. There was no association of booster vaccination with incubation or cycle threshold values. In this cohort study, a booster dose of an inactivated SARS-CoV-2 vaccine provided additional moderate protection against mild infection for 120 days after receipt, but more research is needed to determine the optimal timing of a booster and its effectiveness in preventing severe infection for a longer duration.