Antibody Response Before and After the Booster Dose of Inactivated Corona Vaccine in Antibody Deficient Patients.

Patients with inborn errors of immunity (IEI) are among the high-risk groups regarding COVID-19. Receiving booster doses (third and fourth) in addition to the standard doses is recommended in these patients. This study investigated the antibody response before and after a booster dose of Sinopharm vaccine in IEI patients.  Thirty patients (>12 years) with antibody deficiencies, referred to Imam Khomeini Hospital and Children's Medical Center in Tehran, were enrolled in this prospective cross-sectional study. All patients were fully vaccinated with the BBIBP-CorV vaccine (2 doses of Sinopharm). Initial measurements of anti-receptor-binding domain (anti-RBD) and anti-nucleocapsid (anti-N) IgG antibody responses were conducted by enzyme-linked immunosorbent assay (ELISA). Subsequently, all patients received a booster dose of the vaccine. Four to six weeks after booster injection, the levels of antibodies were re-evaluated.  Twenty patients with common variable immunodeficiency (CVID), 7 cases with agammaglobulinemia and 3 patients with hyper IgM syndrome were studied. Anti-RBD IgG and anti-N IgG antibodies increased in all patients after the booster. Our results indicated the need of receiving booster doses of the COVID-19 vaccine in patients with antibody deficiencies, even for enhancing humoral immune response specially in patients with CVID.

Vaccine Effectiveness Against Severe Acute Respiratory Syndrome Coronavirus 2 Reinfection by Type and Frequency of Vaccine: A Community-Based Case-Control Study.

BACKGROUND: Although guidelines recommend vaccination for individuals who have recovered from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection to prevent reinfection, comprehensive evaluation studies are limited. We aimed to evaluate vaccine effectiveness against SARS-CoV-2 reinfection according to the primary vaccination status, booster vaccination status, and vaccination methods used. METHODS: This population-based case-control study enrolled all SARS-CoV-2-infected patients in Seoul between January 2020 and February 2022. Individuals were categorized into case (reinfection) and control (no reinfection) groups. Data were analyzed using conditional logistic regression after adjusting for underlying comorbidities using multiple regression. RESULTS: The case group included 7,678 participants (average age: 32.26 years). In all vaccinated individuals, patients who received the first and second booster doses showed reduced reinfection rates compared with individuals who received basic vaccination (odds ratio [OR] = 0.605, P < 0.001 and OR = 0.002, P < 0.001). Patients who received BNT162b2 or mRNA-1273, NVX-CoV2373 and heterologous vaccination showed reduced reinfection rates compared with unvaccinated individuals (OR = 0.546, P < 0.001; OR = 0.356, P < 0.001; and OR = 0.472, P < 0.001). However, the ChAdOx1-S or Ad26.COV2.S vaccination group showed a higher reinfection rate than the BNT162b2 or mRNA-1273 vaccination group (OR = 4.419, P < 0.001). CONCLUSION: In SARS-CoV-2-infected individuals, completion of the basic vaccination series showed significant protection against reinfection compared with no vaccination. If the first or second booster vaccination was received, the protective effect against reinfection was higher than that of basic vaccination; when vaccinated with BNT162b2 or mRNA-1273 only or heterologous vaccination, the protective effect was higher than that of ChAdOx1-S or Ad26.COV2.S vaccination only.

Sex-biased immunogenicity of a mucosal subunit vaccine against SARS-CoV-2 in mice.

Introduction: Current vaccines against COVID-19 administered via parenteral route have limited ability to induce mucosal immunity. There is a need for an effective mucosal vaccine to combat SARS-CoV-2 virus replication in the respiratory mucosa. Moreover, sex differences are known to affect systemic antibody responses against vaccines. However, their role in mucosal cellular responses against a vaccine remains unclear and is underappreciated. Methods: We evaluated the mucosal immunogenicity of a booster vaccine regimen that is recombinant protein-based and administered intranasally in mice to explore sex differences in mucosal humoral and cellular responses. Results: Our results showed that vaccinated mice elicited strong systemic antibody (Ab), nasal, and bronchiole alveolar lavage (BAL) IgA responses, and local T cell immune responses in the lung in a sex-biased manner irrespective of mouse genetic background. Monocytes, alveolar macrophages, and CD103+ resident dendritic cells (DCs) in the lungs are correlated with robust mucosal Ab and T cell responses induced by the mucosal vaccine. Discussion: Our findings provide novel insights into optimizing next-generation booster vaccines against SARS-CoV-2 by inducing spike-specific lung T cell responses, as well as optimizing mucosal immunity for other respiratory infections, and a rationale for considering sex differences in future vaccine research and vaccination practice.

Epidemiological characteristics and antibody kinetics of elderly population with booster vaccination following both Omicron BA.5 and XBB waves in China.

After the termination of zero-COVID-19 policy, the populace in China has experienced both Omicron BA.5 and XBB waves. Considering the poor antibody responses and severe outcomes observed among the elderly following infection, we conducted a longitudinal investigation to examine the epidemiological characteristics and antibody kinetics among 107 boosted elderly participants following the Omicron BA.5 and XBB waves. We observed that 96 participants (89.7%) were infected with Omicron BA.5, while 59 (55.1%) participants were infected with Omicron XBB. Notably, 52 participants (48.6%) experienced dual infections of both Omicron BA.5 and XBB. The proportion of symptomatic cases appeared to decrease following the XBB wave (18.6%) compared to that after the BA.5 wave (59.3%). Omicron BA.5 breakthrough infection induced lower neutralizing antibody titers against XBB.1.5, BA.2.86, and JN.1, while reinfection with Omicron XBB broadened the antibody responses against all measured Omicron subvariants and may alleviate the wild type-vaccination induced immune imprinting. Boosted vaccination type and comorbidities were the significant factors associated with antibody responses. Updated vaccines based on emerging severe acute respiratory syndrome coronavirus 2 variants are needed to control the Coronavirus Disease 2019 pandemic in the elderly.

Homologous and Heterologous Covid-19 Booster Vaccinations Against SARS-CoV-2 Infection in the Elderly.

A third booster doses for the 2019 coronavirus disease (COVID-19) is widely used all over the world, especially in risky individuals, with the recommendation of WHO. The purpose of this study was to evaluate the effectiveness of mRNA (BNT162b2), and CoronaVac (Sinovac Biotech) vaccines as a reminder dose following two doses of CoronaVac against COVID-19 infection, serious illness, and mortality in the geriatric population aged 75 and older during the delta variant dominant period. Our study comprised 2730 individuals the age of 75 and older in total, of which 1082 (39.6%) were male and 1648 (60.4%) were female. The vaccine effectiveness (VE) of 2 doses of CoronaVac + 1 dose of BNT162b2 vaccine combination against COVID-19 was determined as 89.2% (95% Confidence interval (CI) 80.7-93.9%), while the VE of 3 doses of CoronaVac vaccine was determined as 80.4% (95% CI 60.5-90.2%). Geriatric patients who received three doses of CoronaVac vaccine did not need intensive care. No deaths were observed in the vaccinated groups. While the VE of vaccination with 2 doses of CoronaVac + 1 dose of BNT162b2 was 41.8% (95% CI 0-74.1%) against hospitalization, 64.4% (95% CI 0-94.7%) against intensive care unit admission, the VE of vaccination with three doses of the CoronaVac was 78.2% (95% CI 0-96.5%) against hospitalization. In conclusion, our research showed that, even with the emergence of viral variants, a third dose of the CoronaVac and BNT162b2 vaccines is highly effective against symptomatic SARS-CoV-2 infection. Third-dose vaccination regimens, including heterologous and homologous vaccines, can be an effective tool in controlling the COVID-19 pandemic and the emergence of new variants.

Influence of grandchildren on COVID-19 vaccination uptake among older adults in China: a parallel-group, cluster-randomized controlled trial.

The uptake of COVID-19 booster vaccination among older adults in China is suboptimal. Here, we report the results of a parallel-group cluster-randomized controlled trial evaluating the efficacy of promoting COVID-19 booster vaccination among grandparents (≥60 years) through a health education intervention delivered to their grandchildren (aged ≥16 years) in a Chinese cohort (Chinese Clinical Trial Registry: ChiCTR2200063240 ). The primary outcome was the uptake rate of COVID-19 booster dose among grandparents. Secondary outcomes include grandparents' attitude and intention to get a COVID-19 booster dose. A total of 202 college students were randomized 1:1 to either the intervention arm of web-based health education and 14 daily reminders (n = 188 grandparents) or control arm (n = 187 grandparents) and reported their grandparents' COVID-19 booster vaccination status at baseline and 21 days. Grandparents in the intervention arm were more likely to receive COVID-19 booster vaccination compared to control cohort (intervention, 30.6%; control, 16.9%; risk ratio = 2.00 (95% CI, 1.09 to 3.66)). Grandparents in the intervention arm also had greater attitude change (ß = 0.28 (95% CI, 0.04 to 0.52)) and intention change (ß = 0.32 (95% CI, 0.12 to 0.52)) to receive a COVID-19 booster dose. Our results show that an educational intervention targeting college students increased COVID-19 booster vaccination uptake among grandparents in China.

Healthcare workers' attitudes toward and factors influencing their acceptance of an annual COVID-19 booster vaccine: a cross-sectional study in Palestine.

BACKGROUND: The emergence of several SARS-CoV-2 variants may necessitate an annual COVID-19 booster vaccine. This study aimed to evaluate healthcare workers' (HCWs) acceptance of a COVID-19 yearly booster vaccine if recommended and its association with their attitudes and burnout levels. METHODS: We used an online self-administered questionnaire to conduct a cross-sectional study of all HCWs in the West Bank and Gaza Strip of Palestine between August and September 2022. We used the Vaccination Attitudes Examination scale to assess HCWs' vaccination attitudes and the Maslach Burnout Inventory to assess work-related Burnout. In addition, we conducted logistic regression to identify factors independently associated with the acceptance of the booster vaccine. RESULTS: The study included 919 HCWs; 52.4% were male, 46.5% were physicians, 30.0% were nurses, and 63.1% worked in hospitals. One-third of HCWs (95% CI: 30.5%-36.7%) said they would accept an annual COVID-19 booster vaccine if recommended. HCWs who are suspicious of vaccine benefits [aOR = .70; 95%CI: .65-.75] and those concerned about unforeseeable future effects [aOR = .90; 95%CI: .84-.95] are less likely to accept the booster vaccine if recommended, whereas those who receive annual influenza vaccine are more likely to get it [aOR = 2.9; 95%CI: 1.7-5.0]. CONCLUSION: Only about a third of HCWs would agree to receive an annual COVID-19 booster vaccine if recommended. Mistrust of the vaccine's efficacy and concerns about side effects continue to drive COVID-19 vaccine reluctance. Health officials need to address HCWs' concerns to increase their acceptance of the annual vaccine if it is to be recommended.

Determination of COVID-19 Late Disorders as Possible Long-COVID and/or Vaccination Consequences.

In this era in which the vast majority of the global population have developed COVID-19 infection and/or got vaccinated against it, identification of the late disorders as the vaccines' side effect or long-COVID manifestation seems essential. This study included the vaccinated individuals of 4 different vaccine regimens including inactivated virus-based, subunit protein, and adenovirus-based vaccines in a follow-up schedule 6-month post the booster shot. All the documented vaccine adverse events were thoroughly assessed considering the cases' medical history by Adverse Events Committee of Pasteur Institute of Iran. Totally 329 individuals who got 3 doses of vaccination were followed 6 months after the booster shots among whom 41 (12.4%) cases with the mean age of 40.9 ± 10.48 years had a type of disorder. Gynecological and osteoarticular involvements were the most common recorded disorders of which 73.1% were possibly linked to vaccination outcomes and the rest were affected by both long-COVID-19 and vaccination. Notably, the average time of symptoms persistence was 155 ± 10.4 days. This study has the advantage of long-term follow-up which presents various forms of late events in each episode of COVID-19 infection and vaccination. About 26.8% of people with persistent complications suffered from both long-COVOD/ vaccination in whom the differentiation between the vaccine side effect and long-COVID manifestation was quite challenging. Long-term follow-up studies in large population seems essential to outline the role of long-COVID and vaccination regarding persistent complications.

Healthcare workers' willingness to receive COVID-19 booster dose and associated factors in the Democratic Republic of the Congo.

The COVID-19 booster dose is considered an important adjunct for the control of the COVID-19 pandemic due to reports of reduced immunity in fully vaccinated individuals. The aims of this study were to assess healthcare workers' intention to receive the booster dose of COVID-19 vaccine and to identify predictive factors among healthcare workers. A cross-sectional study was conducted among healthcare workers selected in two provinces, Kasai Oriental, and Haut-Lomami. Data were collected using a questionnaire administered through structured face-to-face interviews, with respondents using a pre-tested questionnaire set up on the Open Data Kit (ODK Collect). All data were analyzed using SPSS v26.0 (IBM Corporation, Armonk, NY, USA). Vaccination coverage for COVID-19, considering declarations by health workers, is around 85.9% for the province of Kasai Oriental and 85.8% for Haut-Lomami. A total of 975 responses were collected, 71.4% of health workers at Kasai Oriental and 66.4% from Haut-Lomami declared a definite willingness to receive a COVID-19 vaccine booster. The duration of protection was the main reason for accepting a booster COVID-19 dose for 64.6% of the respondents. Logistic regression analysis showed that having chronic diseases (aOR = 2.95 [1.65-5.28]), having already received one of the COVID-19 vaccines (aOR = 2.72 [1.43-5. 19]); the belief that only high-risk individuals, such as healthcare professionals and elderly people suffering from other illnesses, needed a booster dose (aOR = 1.75 [1.10-2.81]). Considering the burden of COVID-19, a high acceptance rate for booster doses could be essential to control the pandemic. Our results are novel and could help policymakers design and implement specific COVID-19 vaccination programs to reduce reluctance to seek booster vaccination.

A two-dose viral-vectored Plasmodium vivax multistage vaccine confers durable protection and transmission-blockade in a pre-clinical study.

Among Plasmodium spp. responsible for human malaria, Plasmodium vivax ranks as the second most prevalent and has the widest geographical range; however, vaccine development has lagged behind that of Plasmodium falciparum, the deadliest Plasmodium species. Recently, we developed a multistage vaccine for P. falciparum based on a heterologous prime-boost immunization regimen utilizing the attenuated vaccinia virus strain LC16m8Δ (m8Δ)-prime and adeno-associated virus type 1 (AAV1)-boost, and demonstrated 100% protection and more than 95% transmission-blocking (TB) activity in the mouse model. In this study, we report the feasibility and versatility of this vaccine platform as a P. vivax multistage vaccine, which can provide 100% sterile protection against sporozoite challenge and >95% TB efficacy in the mouse model. Our vaccine comprises m8Δ and AAV1 viral vectors, both harboring the gene encoding two P. vivax circumsporozoite (PvCSP) protein alleles (VK210; PvCSP-Sal and VK247; -PNG) and P25 (Pvs25) expressed as a Pvs25-PvCSP fusion protein. For protective efficacy, the heterologous m8Δ-prime/AAV1-boost immunization regimen showed 100% (short-term; Day 28) and 60% (long-term; Day 242) protection against PvCSP VK210 transgenic Plasmodium berghei sporozoites. For TB efficacy, mouse sera immunized with the vaccine formulation showed >75% TB activity and >95% transmission reduction activity by a direct membrane feeding assay using P. vivax isolates in blood from an infected patient from the Brazilian Amazon region. These findings provide proof-of-concept that the m8Δ/AAV1 vaccine platform is sufficiently versatile for P. vivax vaccine development. Future studies are needed to evaluate the safety, immunogenicity, vaccine efficacy, and synergistic effects on protection and transmission blockade in a non-human primate model for Phase I trials.

Long-term levels of protection of different types of immunity against the Omicron variant: a rapid literature review.

INTRODUCTION: With the emergence of newer SARS-CoV-2 variants and their substantial effects on the levels and duration of protection against infection, an understanding of these characteristics of the protection conferred by humoral and cellular immunity can aid in the proper development and implementation of vaccine and safety guidelines. METHODS: We conducted a rapid literature review and searched five electronic databases weekly from 1 November 2021 to 30 September 2022. Studies that assessed the humoral or cellular immunity conferred by infection, vaccination or a hybrid (combination of both) in adults and risk groups (immunocompromised and older populations) were identified. Studies were eligible when they reported data on immunological assays of COVID-19 (related to vaccination and/or infection) or the effectiveness of protection (related to the effectiveness of vaccination and/or infection). RESULTS: We screened 5103 studies and included 205 studies, of which 70 provided data on the duration of protection against SARS-CoV-2 infection. The duration of protection of adaptive immunity was greatly impacted by Omicron and its subvariants: levels of protection were low by 3-6 months from exposure to infection/vaccination. Although more durable, cellular immunity also showed signs of waning by 6 months. First and second mRNA vaccine booster doses increased the levels of protection against infection and severe disease from Omicron and its subvariants but continued to demonstrate a high degree of waning over time. CONCLUSION: All humoral immunities (infection-acquired, vaccine-acquired and hybrid) waned by 3-6 months. Cellular immunity was more durable but showed signs of waning by 6 months. Hybrid immunity had the highest magnitude of protection against SARS-CoV-2 infection. Boosting may be recommended as early as 3-4 months after the last dose, especially in risk groups.

Antibody persistence to diphtheria toxoid, tetanus toxoid, Bordetella pertussis antigens, and Haemophilus influenzae type b following primary and first booster with pentavalent versus hexavalent vaccines.

Thailand has incorporated the whole-cell (wP) pertussis vaccine into the expanded program on immunization since 1977 and has offered the acellular pertussis (aP) vaccine as an optional vaccine for infants since 2001. We followed healthy children from a clinical trial (ClinicalTrials.gov NCT02408926) in which children were randomly assigned to receive either pentavalent (DTwP-HB-Hib) or hexavalent (DTaP-IPV-HB-Hib) vaccines for their primary series (administered at 2, 4, and 6 months) and first booster vaccination (18 months). Both groups received Tdap-IPV as a second booster at the age of 4 y. Blood samples were collected for evaluation of antibody persistence to diphtheria toxoid (DT), tetanus toxoid (TT), and Bordetella pertussis (B. pertussis) between 2 and 6 y of age annually, and for the immunogenicity study of Tdap-IPV at 1 month after the second booster. Antibody persistence to Haemophilus influenzae type b (Hib) was followed until 3 y of age. A total of 105 hexavalent-vaccinated children and 91 pentavalent-vaccinated children completed this study. Both pentavalent and hexavalent groups demonstrated increased antibody levels against DT, TT, and B. pertussis antigens following the second booster with Tdap-IPV. All children achieved a seroprotective concentration for anti-DT and anti-TT IgG at 1 month post booster. The hexavalent group possessed significantly higher anti-pertactin IgG (adjusted p = .023), whereas the pentavalent group possessed significantly higher anti-pertussis toxin IgG (adjusted p < .001) after the second booster. Despite declining levels post-second booster, a greater number of children sustained protective levels of anti-DT and anti-TT IgG compared to those after the first booster.

COVID-19 vaccination uptake and determinants of booster vaccination among persons who inject drugs in New York City.

BACKGROUND: Persons who inject drugs (PWID) may be unengaged with healthcare services and face an elevated risk of severe morbidity and mortality associated with COVID-19 due to chronic diseases and structural inequities. However, data on COVID-19 vaccine uptake, particularly booster vaccination, among PWID are limited. We examined COVID-19 vaccine uptake and factors associated with booster vaccination among PWID in New York City (NYC). METHODS: We recruited PWID using respondent-driven sampling from October 2021 to November 2023 in a survey that included HIV and SARS-CoV-2 antibodies testing. The questionnaire included demographics, COVID-19 vaccination and attitudes, and drug use behaviors. RESULTS: Of 436 PWID, 80% received at least one COVID-19 vaccine dose. Among individuals who received at least one COVID-19 vaccine dose, 95% were fully vaccinated. After excluding participants recruited before booster authorization for general adults started in NYC, and those who had never received an initial vaccination, 41% reported having received a COVID-19 booster vaccine dose. COVID-19 booster vaccination was significantly associated with having a high school diploma or GED (adjusted odds ratio (aOR) 1.93; 95% confidence interval (CI) 1.09, 3.48), ever received the hepatitis A/B vaccine (aOR 2.23; 95% CI 1.27, 3.96), main drug use other than heroin/speedball, fentanyl and stimulants (aOR 14.4; 95% CI 2.32, 280), number of non-fatal overdoses (aOR 0.35; 95% CI 0.16, 0.70), and mean vaccination attitude score (aOR 0.94; 95% CI 0.89, 0.98). CONCLUSIONS: We found a suboptimal level of COVID-19 booster vaccination among PWID, which was consistent with the rates observed in the general population in NYC and the U.S. Community-based interventions are needed to improve COVID-19 booster vaccination access and uptake among PWID. Attitudes towards vaccination were significant predictors of both primary and booster vaccination uptake. Outreach efforts focusing on improving attitudes towards vaccination and educational programs are essential for reducing hesitancy and increasing booster vaccination uptake among PWID.

Measles second dose vaccine uptake and its associated factors among children aged 24-35 months in Northwest Ethiopia, 2022.

Measles is a major public health problem in under-five children, leading to lifelong complications. Therefore, the study aimed to assess the magnitude of measles second-dose vaccine uptake and its determinants among children aged 24-35 months in Northwest Ethiopia. A community-based cross-sectional study was conducted among 418 children aged 24-35 months in Northwest Ethiopia between January 2022 and February 2022. A simple random sampling technique was used to access study subjects. A binary logistic regression model was employed. An adjusted odd ratio with a 95% confidence interval (CI) and a p-value < 0.05 was used to declare significant predictors of measles second dose vaccine uptake. The magnitude of the measles second dose vaccine uptake among children aged 24-35 months was 41.39%. Postnatal care visits (AOR: 4.78, CI 1.49, 15.34), child vaccination status of other scheduled vaccines (AOR: 3.88, CI 2.23, 6.73), awareness of the measles second dose vaccine and its schedule (AOR: 8.924, CI 5.27, 15.09), and distance from the vaccination center (AOR: 0.21, CI 0.06, 0.77) were significantly associated with measles second dose vaccine uptake. The uptake of measles second dose vaccine in the study area was low. Therefore, health workers and other partners should initiate awareness creation programs for mothers/caretaker to improve the uptake of measles second dose vaccine.

A prospective humoral immune monitoring study of kidney transplant recipients receiving three doses of SARS-CoV-2 mRNA vaccine.

Kidney transplant recipients (KTRs), like other solid organ transplant recipients display a suboptimal response to mRNA vaccines, with only about half achieving seroconversion after two doses. However, the effectiveness of a booster dose, particularly in generating neutralizing antibodies (NAbs), remains poorly understood, as most studies have mainly focused on non-neutralizing antibodies. Here, we have longitudinally assessed the humoral response to the SARS-CoV-2 mRNA vaccine in 40 KTRs over a year, examining changes in both anti-spike IgG and NAbs following a booster dose administered about 5 months post-second dose. We found a significant humoral response increase 5 months post-booster, a stark contrast to the attenuated response observed after the second dose. Of note, nearly a quarter of participants did not achieve protective plasma levels even after the booster dose. We also found that the higher estimated glomerular filtration rate (eGFR) correlated with a more robust humoral response postvaccination. Altogether, these findings underscore the effectiveness of the booster dose in enhancing durable humoral immunity in KTRs, as evidenced by the protective level of NAbs found in 65% of the patients 5 months post- booster, especially those with higher eGFR rates.

Monkeypox Virus Infections After 2 Preexposure Doses of JYNNEOS Vaccine - United States, May 2022-May 2024.

Two doses of JYNNEOS vaccine are effective in preventing many mpox cases and can reduce the severity of symptoms in infected persons. However, infections among fully vaccinated persons can occur. During May 2022-May 2024, a total of 271 mpox cases among fully vaccinated persons were reported to CDC from 27 U.S. jurisdictions. These reported infections are estimated to have occurred in <1% of fully vaccinated persons. Compared with cases among unvaccinated persons, infections among fully vaccinated persons were more likely to occur among non-Hispanic White men aged 30-39 years, were associated with increased numbers of sexual partners, and resulted in less severe disease (p<0.001). Among infections in fully vaccinated persons with complete data, infections after vaccination were reported more commonly after receipt of heterologous (subcutaneous and intradermal) (46%) or homologous subcutaneous (32%) JYNNEOS vaccination than after homologous intradermal (22%) vaccination. Disparate time intervals from vaccination to infection among fully vaccinated persons suggest that immunity is not waning. The median interval between the second vaccine dose and illness onset was longer for cases among persons who had received 2 intradermal doses (median = 363 days; IQR = 221-444 days) compared with cases in persons who had received 2 subcutaneous doses (median = 263 days; IQR = 47-334 days) (p<0.001). The implications of this finding are not known; however, these data should increase confidence in the effectiveness of vaccine doses that were administered intradermally, the preferred method of administration during the peak of the outbreak when vaccine supply was limited. Persons recommended to receive the JYNNEOS vaccine should receive 2 doses, irrespective of the route of administration, and at this time, additional doses are not recommended for the affected population.

Effectiveness of different booster vaccine combinations against SARS-CoV-2 during a six-month follow-up in Mexico and Argentina.

Introduction: Given the limited number of patients in Latin America who have received a booster dose against the COVID-19, it remains crucial to comprehend the effectiveness of different vaccine combinations as boosters in real-world scenarios. This study aimed to assess the real-life efficacy of seven different vaccine schemes against COVID-19, including BNT162b2, ChAdOx1-S, Gam-COVID-Vac, and CoronaVac as primary schemes with either BNT162b2 or ChAdOx1-S as booster vaccines. Methods: In this multicentric longitudinal observational study, participants from Mexico and Argentina were followed for infection and SARS-CoV-2 Spike 1-2 IgG antibodies during their primary vaccination course and for 185 days after the booster dose. Results: A total of 491 patients were included, and the booster dose led to an overall increase in the humoral response for all groups. Patients who received BNT162b2 exhibited the highest antibody levels after the third dose, while those with primary Gam-COVID-Vac maintained a higher level of antibodies after six months. Infection both before vaccination and after the booster dose, and Gam-COVIDVac + BNT162b2 combination correlated with higher antibody titers. Discussion: The sole predictor of infection in the six-month follow-up was a prior COVID-19 infection before the vaccination scheme, which decreased the risk of infection, and all booster vaccine combinations conveyed the same amount of protection.

A prospective cohort-based artificial intelligence evaluation system for the protective efficacy and immune response of SARS-CoV-2 inactivated vaccines.

BACKGROUND: Novel coronaviruses constitute a significant health threat, prompting the adoption of vaccination as the primary preventive measure. However, current evaluations of immune response and vaccine efficacy are deemed inadequate. OBJECTIVES: The study sought to explore the evolving dynamics of immune response at various vaccination time points and during breakthrough infections. It aimed to elucidate the synergistic effects of epidemiological factors, humoral immunity, and cellular immunity. Additionally, regression curves were used to determine the correlation between the protective efficacy of the vaccine and the stimulated immune response. METHODS: Employing LASSO for high-dimensional data analysis, the study utilised four machine learning algorithms-logistical regression, random forest, LGBM classifier, and AdaBoost classifier-to comprehensively assess the immune response following booster vaccination. RESULTS: Neutralising antibody levels exhibited a rapid surge post-booster, escalating to 102.38 AU/mL at one week and peaking at 298.02 AU/mL at two weeks. Influential factors such as sex, age, disease history, and smoking status significantly impacted post-booster antibody levels. The study further constructed regression curves for neutralising antibodies, non-switched memory B cells, CD4+T cells, and CD8+T cells using LASSO combined with the random forest algorithm. CONCLUSION: The establishment of an artificial intelligence evaluation system emerges as pivotal for predicting breakthrough infection prognosis after the COVID-19 booster vaccination. This research underscores the intricate interplay between various components of immunity and external factors, elucidating key insights to enhance vaccine effectiveness. 3D modelling discerned distinctive interactions between humoral and cellular immunity within prognostic groups (Class 0-2). This underscores the critical role of the synergistic effect of humoral immunity, cellular immunity, and epidemiological factors in determining the protective efficacy of COVID-19 vaccines post-booster administration.

Safety and immunogenicity of COReNAPCIN, a SARS-CoV-2 mRNA vaccine, as a fourth heterologous booster in healthy Iranian adults: A double-blind, randomized, placebo-controlled, phase 1 clinical trial with a six-month follow-up.

The recurrent COVID-19 infection, despite global vaccination, highlights the need for booster doses. A heterologous booster has been suggested to enhance immunity and protection against emerging variants of concern of the SARS-CoV-2 virus. In this report, we aimed to assess the safety, and immunogenicity of COReNAPCIN, as a fourth booster dose after three doses of inactivated vaccines. METHODS: The study was conducted as a double-blind, randomized, placebo-controlled phase 1 clinical trial of the mRNA-based vaccine candidate, COReNAPCIN. The vaccine was injected as a heterologous booster in healthy Iranian adults aged 18-50 who had previously received three doses of inactivated SARS-CoV-2 vaccines. In the study, 30 participants were randomly assigned to receive either COReNAPCIN in two different doses (25 µg and 50 µg) or placebo. The vaccine candidate contained mRNA encoding the complete sequence of the pre-fusion stabilized Spike protein of SARS-CoV-2, formulated within lipid nanoparticles. The primary endpoint was safety and the secondary objective was humoral immunogenicity until 6 months post-vaccination. The cellular immunogenicity was pursued as an exploratory outcome. RESULTS: COReNAPCIN was well tolerated in vaccinated individuals in both doses with no life-threatening or other serious adverse events. The most noticeable solicited adverse events were pain at the site of injection, fatigue and myalgia. Regarding the immunogenicity, despite the seroprevalence of SARS-CoV-2 antibodies due to the vaccination history for all and previous SARS-CoV-2 infection for some participants, the recipients of 25 and 50 µg COReNAPCIN, two weeks post-vaccination, showed 6·6 and 8·1 fold increase in the level of anti-RBD, and 11·5 and 21·7 fold increase in the level of anti-spike antibody, respectively. The geometric mean virus neutralizing titers reached 10.2 fold in the 25 µg group and 8.4 fold in 50 µg group of pre-boost levels. After 6 months, the measured anti-spike antibody concentration still maintains a geometric mean fold rise of 2.8 and 6.3, comparing the baseline levels in 25 and 50 µg groups, respectively. Additionally, the significant increase in the spike-specific IFN-ϒ T-cell response upon vaccination underscores the activation of cellular immunity. CONCLUSION: COReNAPCIN booster showed favorable safety, tolerability, and immunogenicity profile, supporting its further clinical development (Trial registration: IRCT20230131057293N1).

Serosusceptibility and hesitancy for booster HBV vaccination among health care workers in Italy: A cross-sectional study.

BACKGROUND: Health care workers (HCWs) are at increased risk of exposure to hepatitis B virus (HBV). The most effective prevention measure is vaccination, with a serum hepatitis B surface antibody (HBsAb) titre > 10 mIU/ml considered protective. To date, the sociodemographic and occupational characteristics related to HBV serosusceptibility and factors associated with booster hesitancy remain unclear. Therefore, this study aimed to identify factors associated with maintaining a protective HBsAb titre in a large sample of HCWs and to evaluate factors potentially associated with hesitancy towards vaccine boosters. METHODS: A cross-sectional study was conducted among HCWs who underwent a health surveillance visit between 2017 and 2022. If the serum HBsAb titre was < 10 MIU/ml, a vaccine booster dose was offered. Based on their willingness to be vaccinated, employees were classified into three groups: acceptance, hesitation, and refusal. Uni- and multivariable analyses were performed to assess the association of demographic and occupational characteristics with serosusceptibility and attitudes towards vaccination. RESULTS: A total of 1632 (27%) employees were shown to be nonimmune. A lower median age and being a physician were significantly associated with a protective HBsAb titre. A total of 706 nonimmune employees (43.3%) accepted the vaccination, 865 (53%) hesitated, and 61 (3.7%) refused. The median age of those who refused vaccination was significantly higher than that of those who hesitated and those who were vaccinated. Acceptance of vaccination was significantly higher among nurses, while nurse aides hesitated more; among nonmedical graduate staff both hesitation and refusal were higher than expected. In the multivariable analysis, higher age, female sex, and employment as an allied health care professional were shown to be significantly associated with hesitation/refusal, while being born abroad turned out to be protective. CONCLUSIONS: Our study showed that approximately a quarter of HCWs were not immune to HBV infection, and of these, more than half were hesitant towards or refused the booster dose. The risk of hesitation/refusal was higher with age in women and among allied health care staff. Based on these findings, further studies are needed to prospectively evaluate HBV seroprevalence, vaccination adherence, factors associated with hesitancy, and the effectiveness of health surveillance strategies in a high-risk population susceptible to infection.