Vaccine: X最新文献

Human papillomaviruses (HPV) cause 99% of all cervical cancer cases globally, with the high-risk genotypes 16 and 18 causing at least 70% of these cases. An estimated 90% of the global cervical cancer burden occurs in low-to-middle-income countries (LMICs), particularly in sub-Saharan Africa (SSA). Primary prevention through the administration of efficacious HPV vaccines is key to the World Health Organization’s global strategy for accelerating the elimination of cervical cancer as a disease of public health concern. The rollout of HPV vaccination in SSA is faced with several challenges, such as the high cost of vaccine procurement, a lack of funding and political will from the central governments of countries, and inadequate infrastructure for vaccine cold chain storage and transport. Stigma, misinformation, lack of education and awareness, and vaccine hesitancy constitute the social factors that affect the successful rollout or implementation of vaccination programs in SSA. Based on the challenges SSA faces in rolling out HPV vaccination, we recommend using strategies that address both the demand-side and supply-side obstacles to HPV vaccination uptake. These include costs and availability, fighting vaccine hesitancy, and increasing vaccine confidence.

Background

Assessing the risk of measles outbreaks and identifying the susceptible parts of the population is essential to timely intervention. Infants between 6–12 months are increasingly susceptible to measles but evaluating the performance of high throughput enzyme immunoassays (ELISAs) in infants < 9 months of age is lacking.

Methods

A commercially available ELISA kit (Creative Diagnostics, DEIA359) for estimating measles seroprotection was evaluated in infants 5–7 months of age. In an immunogenicity substudy in the Danish MMR trial conducted between 2019–2021, infants (and mothers at baseline) were sampled before and one month after measles-mumps-rubella vaccination (MMR) or placebo as well as one month after routine MMR at 15 months. Measles IgG ELISA was compared to the gold standard but labor-intensive measles plaque reduction neutralization test (PRNT) by Pearson and Spearman correlations and by estimating sensitivity, specificity, and positive and negative predictive values (PPV and NPV).

Findings

Measles IgG levels compared to PRNT antibodies had a Pearson’s correlation coefficient between 0.10–0.24. Seroprotection rates measured by ELISA in young infants were 10–14% lower than measured by PRNT. The sensitivity of the ELISA to detect serological protection compared to PRNT in the infant population differed markedly across sampling time points and was 14%, 40%, and 92% at baseline, post-intervention, and post-routine MMR, whereas the specificity was 99%, 93%, and 43%, respectively. The PPV and NPV were 68% and 87% in infants at baseline.

Interpretation

The correlation between measles IgG and PRNT antibodies was low. Seroprotection was underestimated using ELISA. High-accuracy tests are needed to avoid misclassifications and practices that lead to primary or secondary vaccine failure or retention of vaccination in outbreak settings. Baseline PPV and NPV suggested some applicability of ELISA in predicting serological protection in this age group. However, PRNT may be the only accurate estimator of serological protection in young infants.

Background

Stringent public health and social measures against COVID-19 infection were implemented to avoid an overwhelming hospital caseload and excessive number of deaths, especially among elderly people. We analyzed population-level immunity and predicted mortality, calculated as the potential number of deaths on a given calendar date in Japan, to develop a science-based exit strategy from stringent control measures.

Methods

Immune proportions were inferred by age group using vaccination coverage data and the estimated number of naturally infected individuals. Immunity against symptomatic illness and death were estimated separately, allowing for inference of the immune fraction that was protected against either COVID-19-related symptomatic infection or death. By multiplying the infection fatality risk by age group for the immune fraction, the potential number of deaths was obtained.

Results

Accounting for a second and third dose of messenger RNA vaccine in the present-day population, approximately 155,000 potential deaths would be expected among people aged ≥ 60 years if all individuals were infected at the very end of 2022. A fourth dose (i.e., second booster) with a coverage identical to that of the third dose could reduce mortality by 60%. In all examined settings, the largest number of deaths occurred among people aged 80 years and older.

Conclusions

Our estimates can help policymakers understand the mortality impact of the COVID-19 epidemic in a quantitative manner and the critical importance of timely immunization so as to assist in decision making.

Introduction

Health care workers (HCWs) have been at increased risk of infection during the SARS-CoV-2 pandemic and as essential workers have been prioritised for vaccination. Due to increased exposure HCW are considered a predictor of what might happen in the general population, particularly working age adults. This study aims to summarise effect of vaccination in this ‘at risk’ cohort.

Methods

Ovid MEDLINE and Embase were searched, and 358 individual articles were identified. Of these 49 met the inclusion criteria for review and 14 were included in a meta-analysis.

Results

Participants included were predominantly female and working age. Median time to infection was 51 days. Reported vaccine effectiveness against infection, symptomatic infection, and infection requiring hospitalisation were between 5 and 100 %, 34 and 100 %, and 65 and 100 % (respectively). No vaccinated HCW deaths were recorded in any study. Pooled estimates of protection against infection, symptomatic infection, and hospitalisation were, respectively, 84.7 % (95 % CI 72.6–91.5 %, p < 0.0001), 86.0 % (95 % CI 67.2 %-94.0 %; p < 0.0001), and 96.1 % (95 % CI 90.4 %-98.4 %). Waning protection against infection was reported by four studies, although protection against hospitalisation for severe infection persists for at least 6 months post vaccination.

Conclusions

Vaccination against SARS-CoV2 in HCWs is protective against infection, symptomatic infection, and hospitalisation. Waning protection is reported but this awaits more mature studies to understand durability more clearly. This study is limited by varying non-pharmacological responses to COVID-19 between included studies, a predominantly female and working age population, and limited information on asymptomatic transmission or long COVID protection.

Background

The Herpes Zoster (HZ) poses a significant public health threat, leading to morbidity and occasional mortality in unvaccinated adults aged 50 and older. With over 95 % of individuals in this age group globally having prior exposure to Varicella-Zoster Virus, a substantial portion of the world’s population is susceptible to developing HZ. Without vaccination, individuals reaching 85 years face a 50 % lifetime risk of HZ. Organizational and logistical barriers further hinder vaccination efforts, involving complexities in cost management, demanding vaccine storage requirements, supply limitations, distribution challenges, absence of a streamlined status collection system, and healthcare system deficiencies.

Methods

A systematic review was conducted on the studies that examined the logistical and organizational barriers to HZ vaccination among frail and older adults, aligning with the PRISMA guidelines. Eligibility criteria focus on English studies in Europe, excluding pediatric or irrelevant populations. Rayyan AI was used for data extraction, and bias was assessed using the AXIS tool.

Results

After excluding 841 based on titles and abstracts, 22 publications were selected. A thorough analysis identified 4 studies meeting inclusion criteria, conducted between 2009 and 2022, unveiling several barriers on HZ vaccination: challenges with healthcare professionals, obstacles related to patients’ perceptions and knowledge, difficulties in accessibility, structural issues, social dynamics.

Conclusions

The study represents a comprehensive examination, emphasizing the need for targeted interventions to overcome these barriers. The findings underscore the urgency of addressing these challenges to enhance vaccination rates and mitigate the public health burden associated with HZ.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease (COVID-19), rapidly spread across the globe in 2019. With the emergence of the Omicron variant, COVID-19 shifted into an endemic phase. Given the anticipated rise in cases during the fall and winter seasons, the strategy of implementing seasonal booster vaccines for COVID-19 is becoming increasingly valuable to protect public health. This practice already exists for seasonal influenza vaccines to combat annual influenza seasons. Our goal was to investigate an easily modifiable vaccine platform for seasonal use against SARS-CoV-2. In this study, we evaluated the genetically modified influenza virus ΔNA(RBD) as an intranasal vaccine candidate for COVID-19. This modified virus was engineered to replace the coding sequence for the neuraminidase (NA) protein with a membrane-anchored form of the receptor binding domain (RBD) protein of SARS-CoV-2. We designed experiments to assess the protection of ΔNA(RBD) in K18-hACE2 mice using lethal (Delta) and non-lethal (Omicron) challenge models. Controls of COVID-19 mRNA vaccine and our lab’s previously described intranasal virus like particle vaccine were used as comparisons. Immunization with ΔNA(RBD) expressing ancestral RBD elicited high anti-RBD IgG levels in the serum of mice, high anti-RBD IgA in lung tissue, and improved survival after Delta variant challenge. Modifying ΔNA(RBD) to express Omicron variant RBD shifted variant-specific antibody responses and limited viral burden in the lungs of mice after Omicron variant challenge. Overall, this data suggests that ΔNA(RBD) could be an effective intranasal vaccine platform that generates mucosal and systemic immunity towards SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) emerged as a major global health crisis, posing significant health, economic, and social challenges. Vaccine development has been a crucial response to the severe-acute-respiratory-syndrome-related coronavirus-2 pandemic owing to the critical role of immunization in controlling infectious diseases, leading to the expedited development of several effective vaccines. Although mRNA platform-based COVID-19 vaccines authorized under emergency-use authorization have been administered globally, concerns regarding the vaccines have increased owing to the occurrence of various side effects. The present study aimed to evaluate the safety of a non-replicating recombinant baculovirus expressing the human endogenous retrovirus envelope gene (AcHERV) vaccine encoding SARS-CoV-2 antigens. Owing to the limited number of existing safety pharmacology studies on AcHERV as a viral vector vaccine, we conducted neurobehavior (Modified Irwin’s Test), body temperature, and respiratory function studies in rats and cardiovascular system studies in male beagle dogs, which were administered the AcHERV-COVID-19 vaccine using telemetry. The safety assessment revealed no significant toxicological alterations. However, in rats, both sexes administered with the AcHERV-COVID-19 vaccine exhibited a temporary increase in body temperature, which normalized or showed signs of recovery. In conclusion, AcHERV-COVID-19 demonstrates a sufficient safety profile that supports its potential evaluation in future clinical trials.

Background

Prevention and treatment of the monkeypox virus (Mpox) remain challenging in areas where it is endemic. This systematic review and meta-analysis aimed to collect this information from various studies in one study to give a comprehensive view of people's opinions, fears, and behaviors about this virus.

Methods

We searched PubMed, Scopus, Web of Science, the Cochrane Library, and Google Scholar for descriptive cross-sectional study designs conducted in 2022 and 2023 addressing knowledge, attitude, perception, preparedness, willingness to get vaccinated, and practices against Mpox infection.

Results

Among the included studies, 16 studies assessed the level of knowledge of study participants regarding Mpox with a total of 9066 participants. Among them, 4222 (46.6 %) were reported to have good knowledge, and 4844 (53.4%) were reported to have poor knowledge about Mpox. Regarding willingness to get vaccinated against Mpox, 14 studies with a total of 10,696 participants were included. Among them, 7006 (65 %) were willing to get vaccinated while 3690 (35 %) weren’t willing to be vaccinated.

Conclusion

Knowledge about Mpox should be increased and awareness should be spread regarding the importance of preventive measures such as vaccination to protect the population from another COVID-19-like pandemic.

Since 2022, three human cases of a novel H3N8 avian influenza virus infection have been reported in three provinces in China. Specific vaccines are important means of preparing for the potential influenza pandemic. Thus, H3N8 viruses [A/Henan/cnic410/2022 (HN410) and A/Changsha/1000/2022(CS1000)] were isolated from the infected patients as prototype viruses to develop candidate vaccine viruses (CVVs) using the reverse genetics (RG) technology. Five reassortant viruses with different HA and NA combinations were constructed based on the two viruses to get a high-yield and safe CVV. The results showed that all viruses had similar antigenicity but different growth characteristics. Reassortant viruses carrying NA from CS1000 exhibited better growth ability and NA enzyme activity than the ones carrying HN410 NA. Furthermore, the NA gene of CS1000 had one more potential N-glycosylation site at position 46 compared with HN410. The substitution of position 46 showed that adding or removing N-glycosylation sites to different reassortant viruses had different effects on growth ability. A reassortant virus carrying HN410 HA and CS1000 NA with high growth ability was selected as a CVV, which met the requirements for a CVV. These data suggest that different surface gene combinations and the presence or absence of potential N-glycosylation sites on position 46 in the NA gene affect the growth characteristics of H3N8 CVVs.

Background

India became the first country in the WHO South-East Asia Region (SEAR) to introduce the rotavirus vaccine (RVV) in the Universal immunization programme (UIP) in 2016 with nationwide expansion by 2019. It was a landmark move to reduce the diarrheal disease burden in under-five children. To assess the implementation process of introduction of RVV, Post Introduction Evaluation (PIE) was conducted in March 2022.

Methods

The evaluation was conducted across 14 states, 28 districts and 28 health facilities to obtain a nationwide geographical inclusion. Stakeholders involved in program decision-making, planning, training, vaccine delivery, logistics, and communication from all levels (National, state, district, health facility, health worker, caregiver) were interviewed using standardized data collection tool for PIE (adapted from the standard WHO PIE questionnaire) and scripted on a digital tool.

Results

A total of 260 interviews were conducted. Political willingness, well-planned preparedness activities, securing vaccines timely, strong supply chain monitoring, availability of domestic RVV products, quality trainings and intense communication activities were the key factors identified for the successful RVV introduction. Key activities during the introduction included cold chain space assessment, trainings of healthcare workforce, dissemination of job aids, updation of recording & reporting formats and strengthening of AEFI surveillance. Lack of community awareness for immunization in a few areas, fear of AEFI amongst some caregivers and local issues with Alternate Vaccine Delivery (AVD) were some reported challenges in achieving high coverage for RVV.

Conclusions

Overall, the nationwide roll-out of RVV was smooth and the vaccine has been well-accepted in the community. The assessment emphasizes on having a well-strategized operational and communication planning, which is very crucial for any new vaccine introduction.