BACKGROUND

Pneumococcal vaccination has been widely used for the prevention of pneumococcal disease, with two types of vaccines available since 2009. With the World Health Organization (WHO) recommendation of incorporating pneumococcal conjugate vaccines (PCVs) in National Immunization Programs (NIPs) worldwide, a ten-valent PCV (PHiD-CV) was initially introduced in the Philippines in 2012. This, however, transitioned to the use of the 13-valent PCV (Prevnar) subsequent to the recommendation of the Formulary Executive Council in 2014.

This review aimed to present evidence on pneumococcal disease and vaccine inclusion in the Philippine NIP from 2005 - 2021.

This narrative review compiled articles on Pneumococcus from January 2005 to October 2021, sourcing literature from databases such as BIOSIS Preview, CAB Direct, Embase, Google Scholar, and others.

In the Philippines, there was a shift in prevalent serotypes of Streptococcus pneumoniae among children under five following the introduction of PCV13 in the National Immunization Program in 2014, with serotype 14 becoming the most common by 2018, and a significant reduction in isolates reported in 2020, where only serotypes 5, 19A, and 23F were identified among invasive strains. The immunogenicity results of a potential vaccine candidate should be factored into the overall evidence when conducting a reassessment of PCV.

As part of the decision making about the inclusion of the PCVs in the NIP of the Philippines, various factors such as local epidemiology, vaccine supply, cost, and programmatic characteristics must be careful weighed. Enhancing laboratory and surveillance capacity are essential to provide evidencebased decision-making in terms of existing serotype distribution and antimicrobial resistance (AMR) profile in the country. With the introduction of a new affordable formulation of a 10-valent PCV offering a comparable serotype coverage, the reassessment of choice of PCV with the consideration of all three formulations, namely PCV13, PHiD-CV, and SIIPL-PCV, may be warranted.

Objective To construct a recombinant poxvirus vector vaccine, rVTTδTK-RBD, and to evaluate its safety and immunogenicity. Methods The receptor-binding domain (RBD) gene was synthesized with reference to the gene sequence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was inserted into the polyclonal site of the self-constructed recombinant plasmid pSTKE, to construct the recombinant poxvirus shuttle vector pSTKE-RBD. This was then transfected into BHK-21 cells pre-infected with the vaccinia virus Tiantan strain (VTT). The recombinant poxvirus rVTTδTK-RBD was successfully obtained after several rounds of fluorescence phage screening. The effect of rVTTδTK-RBD on the body mass of BALB/c mice was detected after immunizing mice by intra-nasal vaccination. The levels of specific and neutralizing antibodies produced by rVTTδTK-RBD on BALB/c mice were analyzed after immunizing mice intramuscularly. The effect of rVTTδTK-RBD on T cell subsets in BALB/c mice was detected by flow cytometry. Results Through homologous recombination, enhanced green fluorescent protein (EGFP) screening marker, and multiple rounds of fluorescent phosphorescence phage screening, a recombinant poxvirus rVTTδTK-RBD, expressing RBD with deletions in the thymidine kinase (TK) gene, was successfully obtained, which was validated by PCR. The in vivo experiments on BALB/c mice showed that rVTTδTK-RBD was highly immunogenic against SARS-CoV-2 and significantly reduced toxicity to the body compared to the parental strain VTT. Conclusion The recombinant poxvirus vaccine rVTTδTK-RBD against SARS-CoV-2 is successfully constructed and obtained, with its safety and immunogenicity confirmed through various experiments.
Animals ; Mice ; SARS-CoV-2/genetics* ; COVID-19 ; Vaccines, Synthetic/genetics* ; Genes, Reporter ; Bacteriophages ; Mice, Inbred BALB C

A large number of studies have demonstrated that mRNA vaccine has been characterized as a technique with good safety, strong immunogenicity and high developmental potential, which makes it have broad prospects in immunotherapy. In recent years, the stability and in vivo delivery efficiency of mRNA vaccines have been largely addressed by the progresses in mRNA engineering and delivery innovation. And some mRNA vaccines are now clinical approved or in preclinical trials. Here, we summarize current knowledge on the research advances, technology, and application in major infectious diseases in humans and animals of mRNA vaccines, with the aim to provide a reference for improving the development of novel mRNA vaccines.
Animals ; Humans ; Communicable Diseases ; Vaccines, Synthetic/genetics* ; mRNA Vaccines

To further enhance the immune effect of the foot-and-mouth disease (FMD) virus-like particles (VLPs) vaccine, this study prepared FMDV VLPs-zeolitic imidazolate (framework-8, ZIF-8) complexes with different particle sizes. We used a biomimetic mineralization method with Zn²⁺ and 2-methylimidazole in different concentration ratios to investigate the effect of size on the immunization effect. The results showed that FMDV VLPs-ZIF-8 with three different sizes were successfully prepared, with an approximate size of 70 nm, 100 nm, and 1 000 nm, respectively. Cytotoxicity and animal toxicity tests showed that all three complexes exhibited excellent biological safety. Immunization tests in mice showed that all three complexes enhanced the titers of neutralizing and specific antibodies, and their immune effects improved as the size of the complexes decreased. This study showed that ZIF-8 encapsulation of FMDV VLPs significantly enhanced their immunogenic effect in a size-dependent manner.
Animals ; Mice ; Foot-and-Mouth Disease/prevention & control* ; Foot-and-Mouth Disease Virus ; Antibodies, Neutralizing ; Immunity, Humoral ; Immunization ; Vaccines, Virus-Like Particle ; Antibodies, Viral ; Viral Vaccines

Since the outbreak of corona virus disease 2019 (COVID-19), viral strains have mutated and evolved. Vaccine research is the most direct and effective way to control COVID-19. According to different production mechanisms, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines included inactivated virus vaccine, live attenuated vaccine, mRNA vaccine, DNA vaccine, viral vector vaccine, virus-like particle vaccine and protein subunit vaccine. Among them, viral protein subunit vaccine has a wide application prospect due to its high safety and effectiveness. Viral nucleocapsid protein has high immunogenicity and low variability which could be a new direction for vaccine production. We summarized the current development of vaccine research by reviewing the current progress, vaccine safety and vaccine immune efficiency. It is hoped that the proposed possible development strategies could provide a reference for epidemic prevention work in future.
Humans ; SARS-CoV-2/genetics* ; COVID-19/prevention & control* ; Protein Subunits ; Vaccines, DNA ; Nucleocapsid Proteins

The antigen gene expression level of a DNA vaccine is the key factor influencing the efficacy of the DNA vaccine. Accordingly, one of the ways to improve the antigen gene expression level of a DNA vaccine is to utilize a plasmid vector that is replicable in eukaryotic cells. A replicative DNA vaccine vector pCMVori was constructed based on the non-replicative pcDNA3.1 and the replicon of porcine circovirus 2 (PCV2) in this study. An EGFP gene was cloned into pCMVori and the control plasmid pcDNA3.1. The two recombinant vectors were transfected into PK-15 cell, and the plasmid DNA and RNA were extracted from the transfected cells. Real-time PCR was used to determine the plasmid replication efficiency of the two plasmids using plasmid before and after Bcl Ⅰ digestion as templates, and the transcription level of the Rep gene in PCV2 replicon was detected by RT-PCR. The average fluorescence intensity of cells transfected with the two plasmids was analyzed with software Image J, and the transcription level of EGFP was determined by means of real-time RT-PCR. The results showed that the replication efficiency of pCMVori in PK-15 cells incubated for 48 h was 136%, and the transcriptions of Rep and Rep' were verified by RT-PCR. The average fluorescence intensity of the cells transfected with pCMVori-EGFP was 39.14% higher than that of pcDNA3.1-EGFP, and the transcription level of EGFP in the former was also 40% higher than that in the latter. In conclusion, the DNA vaccine vector pCMVori constructed in this study can independently replicate in eukaryotic cells. As a result, the expression level of cloned target gene was elevated, providing a basis for developing the pCMVori-based DNA vaccine.
Animals ; Swine ; Circovirus/genetics* ; Vaccines, DNA/genetics* ; Replicon/genetics* ; Genetic Vectors/genetics* ; Plasmids/genetics*

Objective: To explore the vaccination coverage of the 13-valent pneumococcal conjugate vaccine (PCV13) in China from 2017 to 2021. Methods: Using the reported number of PCV13 administrated doses from 2017 to 2021 and the population data from 31 provinces in China, which were collected by the Immunization Program Information System and summarized data at different levels (prefecture, provincial, and national). Collecting batch release data of PCV13 during the same period through the official website of the National Institutes for Food and Drug Control. The average coverage level of PCV13 was calculated by comparing the number of PCV13 vaccinations reported annually to the number of births in that year, and the spatial auto-correlation analysis was conducted in 2021 at the prefecture level. The coverage of PCV13 vaccination was estimated by the total vaccine doses administered each year divided by the number of newborn in the year, as of the administrated dose number per 100 people. Results: From March 2017 to December 2020, the total batch release of PCV13 was 20.06 million, with a total of 71.54, 384.75, 475.45, and 10.8886 million doses each year. During the same period, PCV13 reported doses were 20.2369 million and the vaccination doses from 2017 to 2021 were 4.08, 170.46, 407.52, 599.77, and 8.4185 million doses, respectively. From 2017 to 2021, the ratio of PCV13 doses administrated per 100 infants in each year was 0.25, 10.26, 23.81, 38.16, and 69.90 doses per 100 people, respectively. The range of the ratio in each province increased from 3.85 doses in 2017 to 264.41 doses per 100 people in 2021. The spatial auto-correlation analysis results showed that based on prefecture-level cities, there was spatial clustering in a certain area of PCV13 coverage from 2017 to 2021, and the spatial correlation in 2021 was the highest. The hotspot analysis showed that the hotspot areas with high coverage levels of PCV13 were concentrated in Jiangsu, Zhejiang, Shanghai, Fujian and their surrounding areas. The cold spots with low vaccine coverage were concentrated in Yunnan, Qinghai, Tibet, and their surrounding areas. Conclusion: The average coverage level of PCV13 is low in China with significant regional differences.
Infant ; Infant, Newborn ; Humans ; Vaccination Coverage ; Vaccines, Conjugate ; China ; Pneumococcal Vaccines ; Vaccination ; Tibet

This study systematically retrieved information on the payment policy of vaccination fees for pneumococcal vaccines, human papillomavirus vaccines, haemophilus influenzae type b vaccines and rotavirus vaccines using a Python-based crawler. The proportion of the population covered by policies among the total applicable population was estimated based on the medical insurance coverage ratio and population data in 2020. This study showed that the payment policies included two categories, government-funded free vaccination policies and medical insurance payment policies. Among the four non-national immunization program vaccines, the free vaccination policies only involved pneumococcal vaccines and human papillomavirus vaccines. Among them, the 13-valent pneumococcal conjugate vaccine, the 23-valent pneumococcal polysaccharide vaccine, and the human papillomavirus vaccine were provided free of charge in 1, 10 and 15 provinces, respectively. For these policies, the corresponding covered population and the proportion among the total applicable population were children aged 6 months to 2 years old (2.5%), older people (1.2% to 21.5%) and middle school girls (1.1% to 12.2%). Medical insurance payment policies were implemented in 14 provinces, and nearly covered the four types of vaccines in the policy implementation areas, with the proportion of the covered population about 10.9% to 41.5% among the total applicable population.
Child ; Female ; Humans ; Infant ; Aged ; Pneumococcal Vaccines ; Vaccination ; Policy ; Immunization Programs ; Papillomavirus Vaccines ; China ; Vaccines, Conjugate

Objective: Using Meta-analysis to evaluate the vaccine effectiveness of 13-valent pneumococcal conjugate vaccine (PCV13) against invasive Streptococcus pneumoniae disease (IPD) caused by serotype 19A in children <5 years old. Methods: "Streptococcus pneumoniae infection""invasive pneumococcal disease""13-valent pneumococcal polysaccharide conjugate vaccine""PCV13""effectiveness""infant""child" and related terms were searched from China National Knowledge Infrastructure (CNKI), WANFANG DATA, PubMed, SCOPUS and Web of science with no limited on language, region and research institution. The retrieval time was limited from January 2010 to February 2023 and cohort study, case-control study and randomized controlled trial were included. Data were extracted from eligible studies by two independent reviewers, and after study quality assessment by NOS scale, Meta-analysis was completed using Stata 16.0 software. Results: A total of 2 340 related literatures were searched, and 10 literatures were finally included, including 5 case-control studies and 5 indirect cohort studies, which showed good literature quality. The vaccine effectiveness against serotype 19A IPD of PCV13 in children was 83.91% (95%CI: 78.92%-88.89%), and the subgroup analysis (P=0.240) showed there was no significant difference among the case-control study (VE=87.34%, 95%CI:79.74%-94.94%) and the indirect cohort study (VE=81.30%, 95%CI:74.69%-87.92%). The funnel plot and Egger test suggested that the possibility of publication bias was small. Conclusion: The present evidence indicates that PCV13 has a good vaccine effectiveness against serotype 19A IPD in children, and it is recommended to further increase the vaccination rate of PCV13 to reduce the disease burden of IPD in children <5 years old.
Child ; Humans ; Child, Preschool ; Case-Control Studies ; Cohort Studies ; Serogroup ; Vaccines, Conjugate/therapeutic use* ; China ; Pneumococcal Infections/prevention & control*

Objective: To explore the vaccination coverage of the 13-valent pneumococcal conjugate vaccine (PCV13) in China from 2017 to 2021. Methods: Using the reported number of PCV13 administrated doses from 2017 to 2021 and the population data from 31 provinces in China, which were collected by the Immunization Program Information System and summarized data at different levels (prefecture, provincial, and national). Collecting batch release data of PCV13 during the same period through the official website of the National Institutes for Food and Drug Control. The average coverage level of PCV13 was calculated by comparing the number of PCV13 vaccinations reported annually to the number of births in that year, and the spatial auto-correlation analysis was conducted in 2021 at the prefecture level. The coverage of PCV13 vaccination was estimated by the total vaccine doses administered each year divided by the number of newborn in the year, as of the administrated dose number per 100 people. Results: From March 2017 to December 2020, the total batch release of PCV13 was 20.06 million, with a total of 71.54, 384.75, 475.45, and 10.8886 million doses each year. During the same period, PCV13 reported doses were 20.2369 million and the vaccination doses from 2017 to 2021 were 4.08, 170.46, 407.52, 599.77, and 8.4185 million doses, respectively. From 2017 to 2021, the ratio of PCV13 doses administrated per 100 infants in each year was 0.25, 10.26, 23.81, 38.16, and 69.90 doses per 100 people, respectively. The range of the ratio in each province increased from 3.85 doses in 2017 to 264.41 doses per 100 people in 2021. The spatial auto-correlation analysis results showed that based on prefecture-level cities, there was spatial clustering in a certain area of PCV13 coverage from 2017 to 2021, and the spatial correlation in 2021 was the highest. The hotspot analysis showed that the hotspot areas with high coverage levels of PCV13 were concentrated in Jiangsu, Zhejiang, Shanghai, Fujian and their surrounding areas. The cold spots with low vaccine coverage were concentrated in Yunnan, Qinghai, Tibet, and their surrounding areas. Conclusion: The average coverage level of PCV13 is low in China with significant regional differences.
Infant ; Infant, Newborn ; Humans ; Vaccination Coverage ; Vaccines, Conjugate ; China ; Pneumococcal Vaccines ; Vaccination ; Tibet