Vaccine Research
Volume:9 Issue: 2, Summer and Autumn 2022

Vaccines for emerging arboviral diseases that should be a global priority, in a combined strategy with vector control, are being neglected, affecting particularly the poorest populations worldwide. The object of our investigation is to identify the breakthroughs in vaccine innovation for four leading emerging neglected arboviral diseases (Dengue, Chikungunya, Zika and Yellow Fever). From this perspective we examine vaccine patent document applicants by stage of technological development of different vaccine platforms, including the different partnerships established by these applicants.

From a patent landscape approach, we defined  methodological strategies for a hybrid search in two different databases (Derwent Innovation Index and Cortellis Drug Discovery Intelligence) that allowed us to identify the stages of technological development of the vaccines to prevent/treat these four arboviral diseases, making it possible to identify the successful ones that go to clinical trials and the partnerships among private and public institutions, which promote continuity of the development/production process.

Our results confirm these gaps for Dengue, Chikungunya, Zika and Yellow Fever vaccines, with only 13% of these vaccines still under active development and prospect to reach the final stages of development. They also indicate that, in spite of this constraint, innovative platforms such as RNA-based vaccines are increasingly being used to prevent/ treat these diseases. 

We propose urgently strengthening funding and incentive mechanisms in a Global Strategic Plan supported by new business models and community participation to accelerate vaccine development for these four neglected arboviral diseases, a dramatic and concerning global issue in post-COVID-19 era.

Several vaccine platforms have been designed to elicit an effective immune response against SARS-CoV-2. This study was aimed to evaluate the humoral immune response in Iranian people vaccinated with both inactivated virus vaccines and vector vaccine platforms.

The study enrolled 360 vaccinated individuals with inactivated virus vaccines (BBIBP-CorV and Covaxin) and vector vaccine platforms (AstraZeneca and Sputnik V). Serum samples were collected for each volunteer on days 14 to 21 after vaccination, and anti–SARS-CoV-2 spike receptor-binding domain (RBD) IgG concentrations were analyzed by ELISA.

Higher antibody titers were observed in participants vaccinated with vector vaccines compared with those immunized with inactivated virus, especially in subjects who received two doses of AstraZeneca. (AstraZeneca: 204.19 U/mL [95% CI, 175.5-232.2] vs. Sputnik V :114.67 U/mL [95% CI, 99.54-129.8]; P = 0.007). It was also observed that antibody titers were not significantly different between the two groups receiving inactivated vaccines (P = 0.86). Our results indicated that 28% of the population vaccinated with Covaxin and 32% of people vaccinated with BBIBP-CorV showed no response to the vaccine. There was also a statistically insignificant difference between age, BMI, and gender with antibody level in each group of vaccines (P > 0.05).

Based on a limited population data , our study showed that the viral vector-based vaccines produced higher levels of neutralized antibodies than the inactivated vaccines, and their rate of non-response was lesser.

Many efforts were made to control the COVID-19 pandemic in Iran. Such preventive measures, namely, social distancing, vaccination with foreign vaccines and supporting the domestic vaccine production, on-time diagnostic efforts and treatment of the infected put additional pressure on the health system and the country's budget. The COVID-19 crisis has subsided in the country recently, and now is the time to evaluate and review policies in various domains that were adopted during the crisis. Success in policies and implementation of programs is due to good governance which works in the context of a correct decision-making system. Moreover, efforts to reduce health inequality fall within this context. This note is written to emphasize the importance of policy coherence for the access of people to health through vaccination as a hot current issue in vaccination policymaking. Based on the country’s talented human resources and supporting knowledge-based companies, producing domestic vaccines seems to be a reasonable action that could be done through re-skilling or up-skilling as well as a partnership with pioneer companies. However at this point, one should evaluate and assess the outcomes and achievements of these policies and actions, especially in the field of domestic vaccine production. Moreover, the impact of cost-benefit ratio of such actions on the public health system should be evaluated for preparedness during the future pandemics

Extracellular vesicles (EVs), an active biological compounds have significant roles in pathogenesis and intercellular interactions in both Gram-negative and Gram-positive bacteria.. A. muciniphila represents 3–5% of the gut microbiota community and is well-known in individuals with healthy gut through mucin degradation. Moreover, its abundance inversely correlates with body weight. Recently, several studies have been addressed regarding to extracting and obtaining EVs and consequently, many methods are raised to isolate and characterize EVs. The goal of this study was to isolate A. muciniphila EVs from strain ATCC BAA-835 and found out the characterizing of their physico-chemical properties.

The extraction of EVs from A. muciniphila strain ATCC BAA-835 was performed by ultracentrifuge technique. The size and shape of EVs were monitored by transmission electron microscope (TEM) and scanning electron microscope (SEM), and then EVs protein concentrations were assessed by Nano Drop and Bradford, Protein patterns of the EVs were evaluated by SDS-PAGE.

The extracted EVs were confirmed with the shape of vesicles and the sizes ranging from ~ 40 to 150 nm. Total protein concentration of EVs estimated 280nm and 595 nm from two methods; Nano Drop and Bradford, respectively.

The results of the current study indicated that EVs shape, size and conformation were in accepted ranges. Although, subsequent analyses are necessary to clarify the safety, efficacy, practicality and mechanism of this bacterium EVs in clinical studies, especially as vaccine delivery vehicles in the case of vaccine researches.

The detection of endotoxins is crucial in the research and development of new drugs and vaccines, as it ensures the safety of these products. The quantitative Limulus Amebocyte Lysate (LAL) endotoxin tests provide sensitive and accurate results. Quantitative endotoxin tests may be substituted by LAL gel clot test with enough narrow dilution range as a semi-quantitative method. However, the accuracy and reliability of the assay can be affected by the dilution factor used.

The endotoxin concentration of different samples of a bench top purification process of recombinant streptokinase, including inclusion body, washed inclusion body, semi-purified and purified streptokinase was determined by semi-quantitative LAL gel clot and quantitative LAL chromogenic test and the effects of narrow-downing the dilution range of the samples on the accuracy of the results was evaluated.

The statistical analysis revealed that performing duplicate LAL gel clot tests and consecutively narrowing the dilution range of the sample until at least a positive and a negative results were seen, offers a good estimation of the endotoxin concentration. The relative errors of these results were less than 12%, compared to accurate results of quantitative methods. However, conducting gel clot test at the wide dilution range for the inclusion body samples resulted in approximately 200% overestimation.

the results suggest that the semi-quantitative LAL gel clot test with a narrow dilution range can be a valuable tool for relatively accurate estimation of endotoxin in biopharmaceutical products including vaccines

COVID-19 pandemic caused by the emerging SARS-CoV-2, being the cause of COVID-19, leads to acute respiratory syndrome and is a vital threat to global health and the economy since it was identified in late December 2019 in China. Due to the limitations and long-time of vaccine production, most countries were forced to design and produce antigens, kits, and anti-viral drugs so that they might be able to prevent deaths caused by COVID-19. This study was conducted to design and express S1 protein of SARS-CoV-2 to be used as a vaccine candidate.

Recombinant pPICZαA plasmid was replicated in Escherichia coli and the linearized plasmid was transfected into Pichia pastoris yeast as an endosomal fragment. After screening the colonies with Zeocin and confirming the presence of the gene and vector promoter inside the genome extracted from yeast, the expression of S1 protein was induced in BMMY medium with methanol.

  The S1 protein was successfully expressed in P. pastoris and the results obtained on the SDS-PAGE indicated the presence of a protein with 130 kDa molecular weight, confirmed by Western blotting.

The results of the present study showed that the yeast expression system of P. pastoris can be a suitable method to produce glycoprotein S1 as a vaccine candidate or a diagnostic antigen against COVID-19.

Several types of COVID-19 vaccines have been developed so far for the public use. In this study, we aimed to evaluate the effectiveness of different types of COVID-19 vaccines (i.e., viral vector, conjugated and inactivated virus) and the effects of the number of injected doses on the associated risks.

Patients with positive PCR test results for COVID-19 who had been admitted to the Infectious Disease Screening Center (IDSC) of Jiroft in Iran were included in this study. Information from the patients' medical records from February 2022 to June 2022 was collected, retrospectively.

In total, 309 COVID-19 patients (48.5% male and 51.5% female) with a mean age of 39.9±16.7 were included in this study. Our result showed that the viral vector vaccines reduced the chance of hospitalization by 67 % (14.3% in vaccinated patients vs. 73.3% in the unvaccinated group). Moreover, the odds of hospitalization in patients who had received the same type of vaccines as their first dose and their boosters were four times higher than the other patients (17.4% vs. 5.6%) (P=0.02). Also, the analysis of our data illustrated that as the number of the vaccines and the boosters increased, the chance of getting severe COVID-19 decreased (P<0.001), and none of the patients who had received 3 doses of the boosters were hospitalized due to COVID-19. However, There was no significant relationship between the status of the patients (inpatient or outpatient) and the time interval between COVID-19 vaccines and their boosters (P>0.05).

Overall, the viral vector vaccines such as AstraZeneca and Sputnik-V were most successful in reducing the hospitalization rate of COVID-19 patients

Tuberculosis (TB) is one of the deadliest infectious diseases in the world; therefore, controlling TB epidemics is one of the main priorities of global public health. According to the priorities of the World Health Organization, developing and designing new vaccines are needed more than ever to control the spread of this disease. Meanwhile, efforts to produce new drugs against the infection can be effective for the treatment of the disease. Today, the only approved vaccine for TB prevention is Bacille Calmette-Guerin (widely known as BCG) which cannot provide immunity in adults. As a result, researchers have done many investigations in clinical development and pre-clinical trials to prepare new vaccines and to examine new candidates to replace or enhance BCG vaccine. This review investigates the history of BCG vaccine, its limitations as well as recent advances to improve its immunogenicity while reducing its side effects. Moreover, other TB vaccines along with new TB vaccine candidates in clinical trials are presented in this article.