Poliovirus Research Articles

KEJADIAN LUAR BIASA POLIOMIELITIS DI INDONESIA PADA TAHUN 2022-2023: SUATU TINJAUAN

Indonesia achieved polio eradication along with several other members of the Southeast Asia Regional Organization (SEARO) in 2014 because it succeeded in overcoming the disease caused by the wild polio virus. Unfortunately since then Indonesia has experienced several reported outbreaks. This literature review aims to analyze the factors causing the re-emergence of poliomyelitis in Indonesia after being declared polio-free in 2014 and effective steps to stop outbreaks and prevent the re-emergence of poliomyelitis. Awareness of health workers and the public regarding polio must be increased so that Indonesia and the world can soon be polio-free. The last two outbreaks occurred in Indonesia in 2022 and 2023. The first outbreak in 2022 was in Pidie Regency, Aceh, Indonesia. In response to the poliomyelitis outbreak, the government immediately launched a simultaneous vaccination program. Since then no cases of poliomyelitis have been found until another case was found in December 2023 in Solo, Central Java, Indonesia. Once again, to respond to the poliomyelitis outbreak, the government held a simultaneous vaccination program in three districts, namely Pamekasan and Sampang, East Java and Klaten, Central Java. Followed after that by all regions in Central Java and East Java. It is expected that this quick response from the government can stop the outbreak again. The target of SubPIN (National Immunization Subweek) is to break the chain of transmission, so it must ensure that Outbreaks Response Immunization (ORI) coverage is high at least 95% and evenly distributed throughout the region. Apart from that, information to the public regarding the dangers of disease and the importance of complete vaccination to prevent disease must continue to be provided.

Trends in childhood vaccination in Pakistan and associated factors; 2006–2018

IntroductionPakistan still has ongoing transmission of wild type polio virus. This study aims to determine changes in full vaccination with recommended Expanded Program on Immunization vaccines, including polio, by several socio-economic and demographic factors. MethodsWe used three waves of Pakistan’s Demographic and Health Survey, a population-based cross-sectional study from 2006–07 (N = 1471), 2012–13 (N = 1706), and 2017–18 (N = 1549), analyzed by residence, wealth, and sociodemographic factors. Analysis was limited to children aged 12–23 months in Punjab, Sindh, Northwest Frontier Province/Khyber Pakhtunkhwa and Balochistan. Full vaccination was measured as receipt of one Bacillus Calmette–Guérin dose, one measles dose, 3 polio doses, and 3 Diphtheria-Tetanus-Pertussis doses. Odds ratios (ORs) and 95 % confidence intervals (CIs) from logistic regression were used to determine associations between undervaccination and demographic variables. ResultsFull vaccination coverage was 50.6 % in 2006–07, 54.7 % in 2012–13, and 68.3 % in 2017–18. In 2006–07, the odds of undervaccination were significantly higher in Sindh (OR: 1.74, 95 % CI: 1.30, 2.31) than Punjab, and disparities across province changed over time (P < 0.0001); notably, undervaccination was significantly higher in Sindh, KPK, and Balochistan than Punjab in 2017. Compared to the middle wealth quintile, the poorest had significantly higher odds of undervaccination in 2006–07 (OR: 2.58, 95 % CI: 1.76, 3.78), and this did not significantly change over time (P = 0.2168). The proportion of those with a polio birth dose increased across waves from 56.3 % in 2006–07 to 83.7 % in 2017–18; receiving three or more polio vaccine doses remained unchanged. ConclusionThis study showed that the proportion of fully vaccinated children in Pakistan increased across three waves. Full vaccination and administration of polio vaccine birth doses have increased recently in Pakistan. The association between undervaccination with province differed significantly across the waves, with vaccination disparities between provinces increasing. Those in the poorest wealth quintile had the greatest odds of undervaccination.

Is it time to switch to a formulation other than the live attenuated poliovirus vaccine to prevent poliomyelitis?

The polioviruses (PVs) are mainly transmitted by direct contact with an infected person through the fecal-oral route and respiratory secretions (or more rarely via contaminated water or food) and have a primary tropism for the gut. After their replication in the gut, in rare cases (far less than 1% of the infected individuals), PVs can spread to the central nervous system leading to flaccid paralysis, which can result in respiratory paralysis and death. By the middle of the 20th century, every year the wild polioviruses (WPVs) are supposed to have killed or paralyzed over half a million people. The introduction of the oral poliovirus vaccines (OPVs) through mass vaccination campaigns (combined with better application of hygiene measures), was a success story which enabled the World Health Organization (WHO) to set the global eradication of poliomyelitis as an objective. However this strategy of viral eradication has its limits as the majority of poliomyelitis cases today arise in individuals infected with circulating vaccine-derived polioviruses (cVDPVs) which regain pathogenicity following reversion or recombination. In recent years (between January 2018 and May 2023), the WHO recorded 8.8 times more cases of polio which were linked to the attenuated OPV vaccines (3,442 polio cases after reversion or recombination events) than cases linked to a WPV (390 cases). Recent knowledge of the evolution of RNA viruses and the exchange of genetic material among biological entities of the intestinal microbiota, call for a reassessment of the polio eradication vaccine strategies.

Serological investigation on the prevalence of poliovirus in Guangdong province: A cross-sectional study

ABSTRACT In 2019, we conducted a cross-sectional study for polio virus seroprevalence in Guangdong province, China. We assessed the positivity rates of poliomyelitis NA and GMT in serum across various demographic groups, and the current findings were compared with pre-switch data from 2014. Using multistage random sampling method, four counties/districts were randomly selected per city, and within each, one general hospital and two township hospitals were chosen. Healthy individuals coming for medical checkups or vaccination were invited. A total of 1318 individual samples were collected and tested. In non-newborn population, age-dependent positivity rates ranged from 77.8% to 100% for PV1 NA and 70.3% to 98.9% for PV3 NA (p < .01). The lowest GMT values for both types (17.03 and 8.46) occurred in the 20 to <30 years age group, while peak GMTs for PV1 and PV3 were observed in 1 to <2 (340.14) and 0 to <1-year (168.90) age groups, respectively. GMTs for PV1 (P = .002) and PV3 (P = .007) in Eastern Guangdong were lower than those in the other three regions. Male participants showed higher GMTs than females (P = .016 and .033, respectively). In newborn population, both males and females showed higher PV1 NA positivity rates and GMTs compared to PV3 (p < .05). Post-switch PV3 NA positivity rates were higher than pre-switch rates (p = .016). GMTs of both PV1 and PV3 were significantly higher post-switch (p < .001). The positivity rates of NAs and GMTs remain high level, which play an important role in resisting poliomyelitis infection. Effect of the converted immunization program was more pronounced than that before.

Opening a 60-year time capsule: sequences of historical poliovirus cold variants shed a new light on a contemporary strain.

Polioviruses (PVs) are positive strand RNA viruses responsible for poliomyelitis. Many PVs have been isolated and phenotypically characterized in the 1940s-50s for the purpose of identifying attenuated strains that could be used as vaccine strains. Among these historical PVs, only few are genetically characterized. We report here the sequencing of four PV strains stored for more than 60 years in a sealed box. These PVs are cold variants that were selected by Albert Sabin based on their capacity to multiply at relatively low temperatures. Inoculation of permissive cells at 25°C showed that two of the four historical virus stocks still contained infectious particles. Both viruses reached titres that were higher at 25°C than at 37°C, thus demonstrating that they were genuine cold variants. We obtained sequences that span virtually all the genome for three out of the four strains; a short sequence that partly covers the 5' untranslated region was recovered for the last one. Unexpectedly, the genome of one historical cold variant (which derives from PV-3 Glenn) displayed a very high nucleotide identity (above 95%) with that of a PV strain (PV-3 strain WIV14) sampled in China in 2014 and then classified as a highly evolved vaccine-derived PV. Our analyses made this hypothesis very unlikely and strongly suggested that Glenn and WIV14 shared a very recent common ancestor with one another. Some strains used to produce the inactivated polio vaccine were also very close to Glenn and WIV14 in the capsid-encoding region, but they had not been sequenced beyond the capsid. We therefore sequenced one of these strains, Saukett A, which was available in our collection. Saukett A and WIV14 featured an identity higher than 99% at the nucleotide level. This work provides original data on cold variants that were produced and studied decades ago. It also highlights that sequences of historical PV strains could be crucial to reliably characterize contemporary PVs in case of release from a natural reservoir or from a facility, which is of highest importance for the PV eradication program.

Nanoparticles with a Lipid Core Can Enhance the Infection of Epithelial Cells with an Enterovirus.

The effect of maltodextrin-based nanoparticles with an anionic phospholipid core (lipid-based nanoparticles [NPLs]) on the infection of a human tumoral cell line with poliovirus (PV) has been studied. NPLs were synthesized and associated with the PV type 1 Sabin strain, and the formulations were characterized. PV and PV/NPL formulations were inoculated to HEp-2 cells. The surface charge and the diameter of PV/NPL formulation suggest that viral particles were adsorbed onto NPLs. When HEp-2 cells were inoculated with 1 tissue culture 50% infectious dose/mL PV associated with NPLs, the cytopathic effect appeared obvious; the levels of the infectious titer of culture supernatants and the proportion of VP1-positive cells were higher. The level of intracellular viral RNA extracted from HEp-2 cells inoculated with PV/NPL formulation was higher as well. These results show that NPLs can enhance the infection with a virus and suggest that they might be used in virotherapy to increase the virus-mediated lysis of tumor cells.

Improvements of acute flaccid paralysis and measles surveillance performances in response to outbreak of circulating vaccine derived polio virus (2021-2022): the case of Southwest Ethiopia Province, Ethiopia

Improvements of acute flaccid paralysis and measles surveillance performances in response to outbreak of circulating vaccine derived polio virus (2021-2022): the case of Southwest Ethiopia Province, Ethiopia

Failure of poliomyelitis eradication campaign with oral vaccine: there's no vaccination without adherence

Thirty-five years after its launch, the Global Polio Eradication Initiative has yet to reach its original goal of 2000. Not only is the wild type 1 polio virus still endemic in two countries, but a new outbreak due to viruses derived from the live attenuated virus used for the oral vaccine has been spreading since 2016. The National Immunization Days (NID), during which teams go door-to-door and attract children to be vaccinated, have provoked violent opposition particularly in Northern Nigeria and in the area of India, Pakistan, Afghanistan. In both regions, the same rumor has developed that the vaccine contains sterilizing products, in order to limit the Muslim population. The organizers of the campaign multiplied in vain the NIDs to overcome the resistance, but pockets of insufficiently vaccinated population have persisted. This has allowed the wild virus to remain endemic and the new outbreak of vaccine-derived viruses to progress. We can wonder what the campaign would have become if its organizers had taken the time to reflect and reorient their strategy to rely on the routine vaccination of the Expanded Program on Immunization that does not arouse such opposition.

Surveillance of Wastewater Bodies from Bannu, Khyber Pakhtunkhwa, Pakistan for Poliovirus

Poliomyelitis is a viral disease caused by the poliovirus (PV), globally. This virus is responsible for Acute Flaccid Paralysis (AFP) in children in Pakistan. Due to this virus, thousands of children are paralyzed. This virus is transmitted through wastewater in a congested population. The target group of polioviruses comprises the children with no vaccination history. Different factors are involved which create hurdles in the process of vaccination. Some of them are false beliefs, as well as the lack of security for the vaccination team in different areas of Pakistan, especially in the Khyber Pakhtunkhwa (KPK) region. KPK is one of the few remaining regions in the world with a high rate of PV outbreaks. In KPK, District Bannu is among the districts with the highest number of cases of PV.

T Cell Ig and ITIM Domains (TIGIT) Expression in Multiple Myeloma

Background Neoplastic myeloma cells show a wide variety of mechanisms that induce the microenvironment, allowing immune evasion and promoting their proliferation, survival, migration and drug resistance. In this context, immunocheckpoints are particularly important, representing the modulators of signal pathways responsible for immune tolerance, a mechanism that prevents the destruction of cancer cells by the immune system. T cell Ig and ITIM domains (TIGIT), a member of the poliovirus (PVR) /nectin receptor family, is a new immune checkpoint that negatively regulates T cell functions. In Multiple Myeloma (MM), TIGIT could play a relevant role leading to immunological escape. TIGIT performs its task mainly through binding ligands: CD155 and CD112, through which it inhibits the cytotoxicity of CD8+ T cells, as well as that of NK. In This Study, we evaluate the presence of TIGIT in bone marrow using instant digital pathology. AIMS Aims of this study are to develop a valid and reproducible workflow for instant digital pathology, to demonstrate the presence of TIGIT-positive T lymphocytes in bone marrow of patients with MM and to evaluate its correlation with clinical features PATIENTS and Methods 18 patients with newly diagnosed MM not previously treated, were evaluated in this study. The sample was enrolled from November 2022 to May 2023. Bone marrow blood was loaded on a porous matrix able to retain cells (Cytomatrix, UCS Diagnostics srl, Rome) for real time assessment of sample adequacy, morphological details preservation, and composition of hematopoietic subpopulations, using an ex-vivo fluorescent confocal microscope (FCM). Expert pathologists compared the digital FCM images with permanent Formalin Fixed Paraffin Embedded (FFPE) sections of the matrix and trephine bone marrow biopsy. Immunohistochemistry for TIGIT (TG-1 Clone, OncoDianova) was performed on matrix FFPE sections. RESULTS Our results showed that 15/17 (88%) patients resulted positive for TIGIT and 2/17 (12%) were negative. TIGIT expression was found mainly on CD8+ T lymphocytes, TIGIT positivity was correlated with parameters that define the aggressiveness of myeloma disease such as PC &amp;gt; 60% or FLC &amp;gt; 100, ISS score, R-ISS score, cytogenetic risk and LDH &amp;gt; 220mU/ml. Among the patients defined as “ultra-High Risk”, 9/10 (90%) resulted positive for TIGIT. Comparing TIGIT with the MM International Staging System (ISS), we observed that all patients with scores II and III were positive for TIGIT (100%) while 78% of them with ISS I results positive. Conclusions Our results suggest that FCM can be applied immediate evaluation of bone marrow aspirates, preserving the cellular sample for final histological analysis. “Furthermore, our data shows the positivity of TIGIT in 88% of patients, demonstrating the presence of this immune checkpoint in the bone marrow microenvironment. These data will need to be confirmed in a larger group of patients, but they open up the possibility of new target treatments in multiple myeloma

Brain metastasis-associated fibroblasts secrete fucosylated PVR/CD155 that induces breast cancer invasion

Brain metastasis cancer-associated fibroblasts (bmCAFs) are emerging as crucial players in the development of breast cancer brain metastasis (BCBM), but our understanding of the underlying molecular mechanisms is limited. In this study, we aim to elucidate the pathological contributions of fucosylation (the post-translational modification of proteins by the dietary sugar L-fucose) to tumor-stromal interactions that drive the development of BCBM. Here, we report that patient-derived bmCAFs secrete high levels of polio virus receptor (PVR), which enhance the invasive capacity of BC cells. Mechanistically, we find that HIF1α transcriptionally upregulates fucosyltransferase 11, which fucosylates PVR, triggering its secretion from bmCAFs. Global phosphoproteomic analysis of BC cells followed by functional verification identifies cell-cell junction and actin cytoskeletal signaling as modulated by bmCAF-secreted, -fucosylated PVR. Our findings delineate a hypoxia- and fucosylation-regulated mechanism by which bmCAFs contribute to the invasiveness of BCBM in the brain.

A circulating vaccine-derived poliovirus type 2 outbreak in a chronic conflict setting: a descriptive epidemiological study in South Sudan – 2020 to 2021

BackgroundIn this study, we describe the epidemiological profile of an outbreak of the circulating Vaccine Derived Polio Virus type 2 in South Sudan from 2020 to 2021.MethodWe conducted a retrospective descriptive epidemiological study using data from the national polio/AFP surveillance database, the outbreak investigation reports, and the vaccination coverage survey databases stored at the national level.ResultsBetween September 2020 and April 2021, 59 cases of the circulating virus were confirmed in the country, with 50 cases in 2020 and 9 cases in 2021. More cases were males (56%) under five (93%). The median age of the cases was 23.4 ± 11.9 months, ranging from 1 to 84 months. All states, with 28 out of the 80 counties, reported at least one case. Most of the cases (44, 75%) were reported from five states, namely Warrap (31%), Western Bahr el Ghazal (12%), Unity (12%), Central Equatoria (10%), and Jonglei (10%). Four counties accounted for 45.8% of the cases; these are Gogrial West with 12 (20%), Jur River with 5 (8.5%), Tonj North with 5 (8.5%), and Juba with 5 (8.5%) cases.The immunization history of the confirmed cases indicated that 14 (24%) of the affected children had never received any doses of oral polio or injectable vaccines either from routine or during supplemental immunization before the onset of paralysis, 17 (28.8%) had received 1 to 2 doses, while 28 (47.5%) had received 3 or more doses (Fig. 4). Two immunization campaigns and a mop-up were conducted with monovalent Oral Polio Vaccine type 2 in response to the outbreak, with administrative coverage of 91.1%, 99.1%, and 97% for the first, second, and mop-up rounds, respectively.ConclusionThe emergence of the circulating vaccine-derived poliovirus outbreak in South Sudan was due to low population immunity, highlighting the need to improve the country’s routine and polio immunization campaign coverage.

Strengthening immunization programs through innovative sub-national public-private partnerships in selected provinces in the Democratic Republic of the Congo

BackgroundLow immunization coverage rates in the Democratic Republic of Congo (DRC) have been reflective of challenges with vaccine access, support and delivery in the country. Motivated by measles and vaccine-derived polio virus (VDPV) outbreaks in 2016–17 and low vaccination rates, the provinces of Haut Lomami and Tanganyika were identified as pilot locations for an innovative approach focused on establishing a consortium of partners supporting local government. This approach was formalized through Memorandums of Understanding (MoUs) between the Bill and Melinda Gates Foundation and Provincial governments in 2018. A third province, Lualaba, established an MoU in 2021. MoU implementationThese MoUs were 5-year partnerships designed to aid provinces in meeting four key objectives: 80 % immunization coverage, management/elimination of polio/cVDPV outbreaks, improvement of vaccine accessibility, and transfer of immunization service management to provincial leadership. OutcomesDuring the MoU period, Haut-Lomami saw an increase in full immunization coverage, from 35.7 % (MICS 2018) to 88.9 % (VCS 2021–22), the highest in country. A sharp drop in percentage of zero-dose children was observed in the 3 provinces, confirming improved access to immunization services. Tanganyika saw initial improvement in full immunization coverage, followed by a drop in the VCS 2021–22 due to COVID-19 and healthcare worker strikes. Coverage improved in Tanganyika in the 2023 VCS. The 3 provinces increased their financial contributions to routine immunization and are now the top contributing provinces. While no cVDPV cases were recorded in 2020 and 2021, cVDPV1 and cVDPV2 outbreaks are afflicting the 3 provinces since 2022. ConclusionsUltimately, the provincial MoUs were successful in bolstering provincial autonomy and capacity building with the biggest success being a drop in zero-dose children. While not all objectives have been met, the MoU approach served as an innovative program for key aspects of strengthening routine immunization in the DRC.

Comparative Evaluation of HEP-2(Cincinnati) and Vero cell lines sensitivity to Bivalent Oral Polio Virus Vaccine (Type 1 and Type 3) by using In-vitro Microtitration Potency Assay

Comparative Evaluation of HEP-2(Cincinnati) and Vero cell lines sensitivity to Bivalent Oral Polio Virus Vaccine (Type 1 and Type 3) by using In-vitro Microtitration Potency Assay

Evaluation of Direct Detection Protocols for Poliovirus from Stool Samples of Acute Flaccid Paralysis Patients.

Polio surveillance in the Global Polio Eradication Initiative has been conducted with virus isolation from stool samples of acute flaccid paralysis (AFP) cases. Under the current biorisk management/regulations, challenges arise in the timelines of the report, sensitivity of the test and containment of poliovirus (PV) isolates. In the present study, we evaluated protocols of previously reported direct detection (DD) methods targeting the VP1 or VP4-VP2 regions of the PV genome in terms of sensitivity and sequencability. An optimized protocol targeting the entire-capsid region for the VP1 sequencing showed a high sensitivity (limit of detection = 82 copies of PV genome) with a simpler and faster reaction than reported ones (i.e., with the addition of all the primers at the start of the reaction, the RT-PCR reaction finishes within 2.5 h). The DD methods targeting the VP1 region detected PV in 60 to 80% of PV-positive stool samples from AFP cases; however, minor populations of PV strains in the samples with virus mixtures were missed by the methods. Sequencability of the DD methods was primarily determined by the efficiency of the PCRs for both Sanger and nanopore sequencing. The DD method targeting the VP4-VP2 region showed higher sensitivity than that targeting the VP1 region (limit of detection = 25 copies of PV genome) and successfully detected PV from all the stool samples examined. These results suggest that DD methods are effective for the detection of PV and that further improvement of the sensitivity is essential to serve as an alternative to the current polio surveillance algorithm.

Wastewater Surveillance in Europe for Non-Polio Enteroviruses and Beyond.

Wastewater surveillance (WWS) was developed in the early 1960s for the detection of poliovirus (PV) circulation in the population. It has been used to monitor several pathogens, including non-polio enteroviruses (NPEVs), which are increasingly recognised as causes of morbidity in children. However, when applying WWS to a new pathogen, it is important to consider the purpose of such a study as well as the suitability of the chosen methodology. With this purpose, the European Non-Polio Enterovirus Network (ENPEN) organised an expert webinar to discuss its history, methods, and applications; its evolution from a culture-based method to molecular detection; and future implementation of next generation sequencing (NGS). The first simulation experiments with PV calculated that a 400 mL sewage sample is sufficient for the detection of viral particles if 1:10,000 people excrete poliovirus in a population of 700,000 people. If the method is applied correctly, several NPEV types are detected. Despite culture-based methods remaining the gold standard for WWS, direct methods followed by molecular-based and sequence-based assays have been developed, not only for enterovirus but for several pathogens. Along with case-based sentinel and/or syndromic surveillance, WWS for NPEV and other pathogens represents an inexpensive, flexible, anonymised, reliable, population-based tool for monitoring outbreaks and the (re)emergence of these virus types/strains within the general population.

PATTERN AND BURDEN OF VARIOUS MYTHS REGARDING POLIO VACCINE AMONG THE PARENTS OR LEGAL GUARDIANS WHO REFUSED POLIO VACCINATION TO THEIR CHILD

Polio is still prevalent worldwide and is yet to be eradicated from Pakistan despite the best efforts of various national and international organizations such as WHO, UNICEF, and UNESCO. A study was conducted to determine the different myths surrounding polio vaccination among parents or legal guardians who refused to vaccinate their children. The study aimed to identify the pattern and burden of various myths regarding the polio vaccine among the parents or legal guardians who refused polio vaccination to their children. This descriptive cross-sectional study was conducted at the Department of Community Medicine, Nishtar Medical University, Multan, in major areas of Multan City from June 25, 2022, to June 24, 2023. Field visits were made to the homes of parents or legal guardians of households who refused polio vaccination on the last 2 consecutive campaigns by EPI. Of the 241 respondents, 154 (63.9%) were males, and 87 (36.1%) were female respondents. The mean age of the study cases was 31.12 ± 4.59 years. The mean number of children was 4.12 ± 1.02, ranging from a minimum of 2 to a maximum of 7. Most of the study participants were illiterate, with only 12 % having education up to the matriculation level, and none having educational level more than matriculation. Of the 241 study cases, 87 (36.1 %) were jobless, 32% were laborers, 12.4% were shopkeepers, 3.7 % had their own business, 11.6 % were farmers, and 4.1 % had private jobs. Of the 241 study participants, 4.1% were Urdu speaking, 23.7% were Punjabi, 44 % were Saraiki, 15.8% were Baloch, and 12.4% were Pathans. The study results showed that 16.6% of the participants reported that the vaccine was unnecessary, and 52.3% reported that the vaccine was harmful. Most parents or guardians who refused to vaccinate their children against the polio virus believed that the vaccine was harmful and unnecessary. The myth that the vaccine is harmful and will make their child sterile was more prevalent. In contrast, the myth that the vaccine is unnecessary was significantly associated with the gender of respondents, education, socioeconomic status, occupation, and ethnicity. On the other hand, the myth that the vaccine is harmful was significantly associated with increasing age, socioeconomic status, education, occupation, and ethnicity.

Predictors of timeliness of vaccination among children of age 12–23 months in Boricha district, Sidama region Ethiopia, in 2019

BackgroundTraditional measurement of vaccine coverage can mask the magnitude of timely uptake of vaccine. Hence, the optimal measurement of timeliness is unclear due to variations in vaccine schedule among countries in the world. In Ethiopia, Oral Polio Virus (OPV), Pentavalent, Tetanus, H. influenza type B, Hepatitis B, and Pneumonia-Conjugate Vaccine (PCV) are basic vaccines which are taken at birth, six weeks, ten weeks, and fourteen weeks respectively. Despite its importance, information is scarce about on-time vaccination in the study area. Therefore, this study aimed to assess prevalence and factors associated with on-time vaccination among children of age 12–23 months in Boricha district, Sidama Ethiopia, in 2019.MethodsA community based survey was conducted in Boricha district, Sidama region Ethiopia from January 1–30 in 2019. Study participants were selected using stratified multistage sampling technique. Kebeles were stratified based on residence. First, Kebeles were selected using random sampling. Then, systematic random sampling was employed to reach each household. Data were collected using structured and interviewer administered questionnaire. Logistic regression analysis was employed to identify factors associated with timely vaccination. Then, independent variables with p-value < 0.25 in COR were fitted further into multivariate logistic regression analysis model to control the possible cofounders. AOR with 95% CI and p-value < 0.05 was computed and reported as the level of statistical significance.ResultsFrom a total of 614 study participants, only 609 study participants have responded to questions completely making a response rate of 99.2%. Prevalence of timeliness of vaccination was 26.8% (95% CI: 25, 28) in this study. Factors like children of women with formal education (AOR = 5.3, 95%CI,2.7, 10.4), absence of antenatal care visit (AOR = 4.2,95%CI, 1.8,9.8), home delivery (AOR = 6.2,95%CI,4.0,9.3), lack of postnatal care (AOR = 3.7,95%CI,1.1,13.3), and lack of information about when vaccines completion date (AOR = 2.0, 95% CI,1.13,3.8) were factors influences timely vaccination among children of age 12–23 months.ConclusionPrevalence of on-time vaccination among children of age 12–23 months is lower than national threshold. Therefore, sustained health education on vaccination schedule and reminder strategies should be designed and implemented. Furthermore, maternal and child health care services should be enhanced and coordinated to improve on-time uptake of vaccine.

Sabin polio virus protein 1 (VP1) evolution in patients with acute flaccid paralysis from 2010 to 2016 in Uganda

Acute flaccid paralysis (AFP) is a rare side effect of the oral polio vaccine but can be associated with outbreaks and permanent disability in patients harboring circulating vaccine-derived polioviruses (cVDPVs). With the advancement of polio abolition in a glimpse, cVDPVs are causing outbreaks and slowing the polio eradication process. The polio virus protein 1 (VP1) contains the binding site that is key for virus transmission. Understanding the evolution of VP1 among AFP patients could yield more insight into the early events of cVDPVs. Polioviruses were identified from stool specimens of AFP patients using cell culture; and confirmed by the real time RT PCR intra-typic differentiation and vaccine-derived poliovirus assays. Seventy-nine (79) Sabin-like poliovirus 1 (SL1) and 86 Sabin-like poliovirus 3 (SL3) were sequenced. The VP1 amino acid substitutions T106A in Sabin poliovirus 1 and A54V in Sabin poliovirus 3 were common among the AFP patients as has been found in previous studies. Other substitutions that were associated with AFP were: T290A and A54T in SL1 and SL3 respectively. Nucleotide mutations that were common among the AFP patients included T402C, C670A, and T816C in SL1, and G22A, C375Y, A472R, and A694T in SL3 polioviruses. Characterizing mutations that are associated with AFP could contribute to efforts pursued to mitigate the risk of vaccine-derived polioviruses and promote development of safer vaccines.

The state of specific immunity of population of the Republic of Tajikistan to measles, rubella, poliomyelitis viruses

Relevance. To achieve the goals of measles and rubella elimination and poliomyelitis eradication programs, immunization coverage of at least 95% of the target population is required. Objective data on the state of specific herd immunity are provided only by the results of serosurveys. In the Republic of Tajikistan, such monitoring is not carried out regularly. Therefore, the purpose of the study was to assess the actual state of the specific herd immunity to measles, rubella, and poliomyelitis viruses.&#x0D; Materials and methods. The blood sera of 563 children and adults collected in 7 cities and 13 districts of Tajikistan in 2020 were investigated. The level of antibodies (ABs) to measles and rubella viruses was determined using enzyme immunoassay. Test systems VectoKor-IgG (VECTOR-BEST, Russia) and Ecolab, Russia were used to determine ABs to measles and rubella virus, respectively. Neutralizing antibodies (nABs) to the 3 types of poliovirus (PV) were determined in 359 sera using a neutralization reaction with Sabin strains of types 1, 2, 3.&#x0D; Results. The conducted serosurvey showed the level of the specific herd immunity to rubella to be 87.9% in total population, including 86.2% in children, 93.1% in adolescents, and 93.5% and adults, that is sufficient to prevent transmission of the rubella virus. The proportion of individuals seropositive to measles was 54.5%, which is not enough to prevent sustained secondary transmission of infection and the resumption of circulation of the endemic strain of measles virus. The children under 15 years of age should be considered a population at risk of the infection, since children accounted for 38% among seronegative individuals.&#x0D; In general, less than 95% of the examined patients had nABs to PV: 94.4% to PV1, 86.1% to PV2, 83.6% to PV3; 3.3% did not have antibodies to all three types of PV. The level of herd immunity varied in the examined groups depending on the vaccination schedule and the composition of the poliovirus vaccines used: nABs to PV2 had 59.6% of children born during the period when vaccines containing PV2 were not used, and 85.7% of children born after the introduction of trivalent IPV. Deficiency in immunity to PV2 was the cause of a polio outbreak in 2021 caused by circulating vaccine-derived PV type 2.&#x0D; Conclusion. A high level of humoral immunity to the rubella virus was determined. Shortcomings of routine immunization against measles and polio associated with insufficient coverage and lack of IPV have been identified. Conducting regular serological monitoring in the Republic of Tajikistan is advisable to obtain objective information about the level of herd immunity, identify vulnerable groups of the population, and plan additional immunization activities.