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Cell Host & Microbe May 2020The live-attenuated oral poliovirus vaccine (OPV or Sabin vaccine) replicates in gut-associated tissues, eliciting mucosa and systemic immunity. OPV protects from...
The live-attenuated oral poliovirus vaccine (OPV or Sabin vaccine) replicates in gut-associated tissues, eliciting mucosa and systemic immunity. OPV protects from disease and limits poliovirus spread. Accordingly, vaccination with OPV is the primary strategy used to end the circulation of all polioviruses. However, the ability of OPV to regain replication fitness and establish new epidemics represents a significant risk of polio re-emergence should immunization cease. Here, we report the development of a poliovirus type 2 vaccine strain (nOPV2) that is genetically more stable and less likely to regain virulence than the original Sabin2 strain. We introduced modifications within at the 5' untranslated region of the Sabin2 genome to stabilize attenuation determinants, 2C coding region to prevent recombination, and 3D polymerase to limit viral adaptability. Prior work established that nOPV2 is immunogenic in preclinical and clinical studies, and thus may enable complete poliovirus eradication.
Topics: Adult; Animals; Chlorocebus aethiops; Disease Models, Animal; Female; Genetic Engineering; HeLa Cells; Humans; Immunogenicity, Vaccine; Male; Mice; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; RNA, Viral; RNA-Dependent RNA Polymerase; Recombination, Genetic; Vaccination; Vaccines, Attenuated; Vero Cells; Virulence
PubMed: 32330425
DOI: 10.1016/j.chom.2020.04.003 -
Bulletin of the World Health... Dec 2023A decrease in vaccine coverage in conflict-affected areas has placed Yemen at higher risk of polio outbreaks caused by vaccine-derived poliovirus strains.
PROBLEM
A decrease in vaccine coverage in conflict-affected areas has placed Yemen at higher risk of polio outbreaks caused by vaccine-derived poliovirus strains.
APPROACH
In response to polio outbreaks, the Yemeni health ministry and partners initiated multiple vaccination campaigns to deliver vaccines to children. We also implemented several measures to enhance communication, education, health promotion and hygiene, especially in camps for internally displaced people.
LOCAL SETTING
In 2009, Yemen achieved polio-free status and maintained it until 2019. However, the ongoing political conflict since 2015, coupled with challenges in delivering the polio vaccine to conflict-affected areas, resulted in two polio outbreaks: 35 cases caused by vaccine-derived poliovirus strain 1 between 2019 and 2021, and 230 cases due to vaccine-derived poliovirus strain 2 between November 2021 and December 2022.
RELEVANT CHANGES
In response to the first outbreak, by the end of 2020, we vaccinated 7.2 million children through nationwide vaccination campaigns, except in Sa'ada governorate due to a ban by the authorities. By the end of 2021, 3 800 313 children younger than 5 years had received polio vaccines. For the second outbreak, by the end of 2022, 4 463 389 vaccines had been given to children younger than 10 years, and 1 217 423 to those younger than 5 years.
LESSONS LEARNT
Vaccination campaigns in conflict-affected areas with low vaccine coverage remain crucial in eradicating polio. Efforts are needed to reach vulnerable groups such as displaced populations. Advocacy, communication and social mobilization actions help ensure broader public inclusion and participation in vaccination efforts to prevent polio outbreaks.
Topics: Child; Humans; Yemen; Poliomyelitis; Poliovirus; Poliovirus Vaccines; Disease Outbreaks
PubMed: 38024246
DOI: 10.2471/BLT.23.290122 -
Pediatrics May 2022The majority of children are prescribed antibiotics in the first 2 years of life while vaccine-induced immunity develops. Researchers have suggested a negative...
BACKGROUND
The majority of children are prescribed antibiotics in the first 2 years of life while vaccine-induced immunity develops. Researchers have suggested a negative association of antibiotic use with vaccine-induced immunity in adults, but data are lacking in children.
METHODS
From 2006 to 2016, children aged 6 to 24 months were observed in a cohort study. A retrospective, unplanned secondary analysis of the medical record regarding antibiotic prescriptions and vaccine antibody measurements was undertaken concurrently. Antibody measurements relative to diphtheria-tetanus-acellular pertussis (DTaP), inactivated polio (IPV), Haemophilus influenzae type b (Hib), and pneumococcal conjugate (PCV) vaccines were made.
RESULTS
In total, 560 children were compared (342 with and 218 without antibiotic prescriptions). Vaccine-induced antibody levels to several DTaP and PCV antigens were lower (P < .05) in children given antibiotics. A higher frequency of vaccine-induced antibodies below protective levels in children given antibiotics occurred at 9 and 12 months of age (P < .05). Antibiotic courses over time was negatively associated with vaccine-induced antibody levels. For each antibiotic course the child received, prebooster antibody levels to DTaP antigens were reduced by 5.8%, Hib by 6.8%, IPV by 11.3%, and PCV by 10.4% (all P ≤ .05), and postbooster antibody levels to DTaP antigens were reduced by 18.1%, Hib by 21.3%, IPV by 18.9%, and PCV by 12.2% (all P < .05).
CONCLUSIONS
Antibiotic use in children <2 years of age is associated with lower vaccine-induced antibody levels to several vaccines.
Topics: Anti-Bacterial Agents; Antibodies, Viral; Child; Child, Preschool; Cohort Studies; Diphtheria-Tetanus-acellular Pertussis Vaccines; Haemophilus Vaccines; Humans; Poliovirus Vaccine, Inactivated; Retrospective Studies; Vaccines, Combined
PubMed: 35474546
DOI: 10.1542/peds.2021-052061 -
Vaccine Oct 2016
Topics: Africa; Disease Eradication; Disease Outbreaks; Humans; Poliomyelitis; Poliovirus Vaccines; Public Health
PubMed: 27595897
DOI: 10.1016/j.vaccine.2016.07.042 -
Epidemiology and Infection Feb 2017Polio cases due to wild virus are reported by only three countries in the world. Poliovirus type 2 has been globally eradicated and the last detection of poliovirus type... (Review)
Review
Polio cases due to wild virus are reported by only three countries in the world. Poliovirus type 2 has been globally eradicated and the last detection of poliovirus type 3 dates to November 2012. Poliovirus type 1 remains the only circulating wild strain; between January and September 2016 it caused 26 cases (nine in Afghanistan, 14 in Pakistan, three in Nigeria). The use of oral polio vaccine (OPV) has been the key to success in the eradication effort. However, paradoxically, moving towards global polio eradication, the burden caused by vaccine-derived polioviruses (VDPVs) becomes increasingly important. In this paper circulation of both wild virus and VDPVs is reviewed and implications for the polio eradication endgame are discussed. Between April and May 2016 OPV2 cessation has been implemented globally, in a coordinated switch from trivalent OPV to bivalent OPV. In order to decrease the risk for cVDPV2 re-emergence inactivated polio vaccine (IPV) has been introduced in the routine vaccine schedule of all countries. The likelihood of re-emergence of cVDPVs should markedly decrease with time after OPV cessation, but silent circulation of polioviruses cannot be ruled out even a long time after cessation. For this reason, immunity levels against polioviruses should be kept as high as possible in the population by the use of IPV, and both clinical and environmental surveillance should be maintained at a high level.
Topics: Afghanistan; Antibodies, Viral; Disease Eradication; Health Policy; Humans; Nigeria; Pakistan; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Inactivated; Poliovirus Vaccine, Oral
PubMed: 27866483
DOI: 10.1017/S0950268816002569 -
The Lancet. Global Health Aug 2021The Global Polio Eradication Initiative, launched in 1988 with anticipated completion by 2000, has yet to reach its ultimate goal. The recent surge of polio cases... (Review)
Review
The Global Polio Eradication Initiative, launched in 1988 with anticipated completion by 2000, has yet to reach its ultimate goal. The recent surge of polio cases urgently calls for a reassessment of the programme's current strategy and a new design for the way forward. We propose that the sustainable protection of the world population against paralytic polio cannot be achieved simply by stopping the circulation of poliovirus but must also include maintaining high rates of population immunity indefinitely, which can be created and maintained by implementing global immunisation programmes with improved poliovirus vaccines that create comprehensive immunity without spawning new virulent viruses. The proposed new strategic goal of eradicating the disease rather than the virus would lead to a sustainable eradication of poliomyelitis while simultaneously promoting immunisation against other vaccine-preventable diseases.
Topics: Disease Eradication; Global Health; Humans; Immunization Programs; Poliomyelitis; Poliovirus Vaccines; Program Evaluation
PubMed: 34118192
DOI: 10.1016/S2214-109X(21)00205-9 -
Nature Reviews. Immunology Dec 2021In August 2020, Africa was declared free of poliomyelitis (polio), bringing to fruition a goal that took more than 30 years to achieve. This Perspective chronicles... (Review)
Review
In August 2020, Africa was declared free of poliomyelitis (polio), bringing to fruition a goal that took more than 30 years to achieve. This Perspective chronicles global, continental, national and community actions taken by diverse stakeholders that finally led to the elimination of transmission of wild poliovirus in Africa. The cascade of events started with the development of polio vaccines and the realization that polio, much like smallpox, could be eradicated. After a 1988 pledge by the World Health Assembly to eradicate polio globally, concerted and deliberate efforts were made in Africa to achieve this goal. This included the use of evidence-based approaches for the harmonization and standardization of public health strategies, using a network of polio laboratories and emergency operation centres and actively pursuing underserved populations. Innovative solutions to counter challenges such as conflict and vaccine hesitancy may be of use in future public health interventions.
Topics: Africa; Animals; Disease Eradication; Global Health; Humans; Poliomyelitis; Poliovirus Vaccines; Vaccination Hesitancy
PubMed: 34697501
DOI: 10.1038/s41577-021-00640-w -
Human Vaccines & Immunotherapeutics Mar 2016Nigeria has made tremendous strides towards eliminating polio and has been free of wild polio virus (WPV) for more than a year as of August 2015. However, sustained... (Review)
Review
Nigeria has made tremendous strides towards eliminating polio and has been free of wild polio virus (WPV) for more than a year as of August 2015. However, sustained focus towards getting rid of all types of poliovirus by improving population immunity and enhancing disease surveillance will be needed to ensure it sustains the polio-free status. We reviewed the pertinent literature including published and unpublished, official reports and working documents of the Global Polio Eradication Initiative (GPEI) partners as well as other concerned organizations. The literature were selected based on the following criteria: published in English Language, published after year 2000, relevant content and conformance to the theme of the review and these were sorted accordingly. The challenges facing the Polio Eradication Initiative (PEI) in Nigeria were found to fall into 3 broad categories viz failure to vaccinate, failure of the Oral Polio Vaccine (OPV) and epidemiology of the virus. Failure to vaccinate resulted from insecurity, heterogeneous political support, programmatic limitation in implementation of vaccination campaigns, poor performance of vaccination teams in persistently poor performing Local Government areas and sporadic vaccine refusals in Northern Nigeria. Sub optimal effectiveness of OPV in some settings as well as the rare occurrence of VDPVs associated with OPV type 2 in areas of low immunization coverage were also found to be key issues. Some of the innovations which helped to manage the threats to the PEI include a strong government accountability frame work, change from type 2 containing OPV to bi valent OPVs for supplementary immunization activities (SIA), enhancing environmental surveillance in key states (Sokoto, Kano and Borno) along with an overall improvement in SIA quality. There has been an improvement in coverage of routine immunization and vaccination campaigns, which has resulted in Nigeria being removed from the list of endemic countries following an absence of new cases for an entire year as of September 2015. However, the last mile remains to be crossed and there is need to further improve and sustain the momentum to complete the journey toward polio elimination.
Topics: Disease Eradication; Humans; Nigeria; Poliomyelitis; Poliovirus Vaccines
PubMed: 26383769
DOI: 10.1080/21645515.2015.1088617 -
MMWR. Morbidity and Mortality Weekly... Jul 2023This report describes the status of introductions globally for eight World Health Organization (WHO)-recommended new and underutilized vaccines, comprising 10 individual...
This report describes the status of introductions globally for eight World Health Organization (WHO)-recommended new and underutilized vaccines, comprising 10 individual vaccine antigens. By 2021, among 194 countries worldwide, 33 (17%) provided all of these 10 WHO-recommended antigens as part of their routine immunization schedules; only one low-income country had introduced all of these recommended vaccines. Universal hepatitis B birth dose; human papillomavirus vaccine; rotavirus vaccine; and diphtheria, tetanus, and pertussis-containing vaccine first booster dose have been introduced by 57%, 59%, 60%, and 72% of all countries worldwide, respectively. Pneumococcal conjugate vaccine, rubella-containing vaccine, measles-containing vaccine second dose, and Haemophilus influenzae type b vaccine have been introduced by 78%, 89%, 94%, and 99% of all countries, respectively. The annual rate of new vaccine introductions declined precipitously when the COVID-19 pandemic started, from 48 in 2019 to 15 in 2020 before rising to 26 in 2021. Increased efforts to accelerate new and underutilized vaccine introductions are urgently needed to improve universal equitable access to all recommended vaccines to achieve the global Immunization Agenda 2021-2030 (IA2030) targets.
Topics: Humans; Infant; Diphtheria-Tetanus-Pertussis Vaccine; Pandemics; Haemophilus Vaccines; COVID-19; Vaccination; Measles Vaccine; Rubella Vaccine; Immunization Schedule; Poliovirus Vaccine, Inactivated; Hepatitis B Vaccines; Vaccines, Combined
PubMed: 37410663
DOI: 10.15585/mmwr.mm7227a2 -
Nature Jul 2023Vaccination with Sabin, a live attenuated oral polio vaccine (OPV), results in robust intestinal and humoral immunity and has been key to controlling poliomyelitis. As...
Vaccination with Sabin, a live attenuated oral polio vaccine (OPV), results in robust intestinal and humoral immunity and has been key to controlling poliomyelitis. As with any RNA virus, OPV evolves rapidly to lose attenuating determinants critical to the reacquisition of virulence resulting in vaccine-derived, virulent poliovirus variants. Circulation of these variants within underimmunized populations leads to further evolution of circulating, vaccine-derived poliovirus with higher transmission capacity, representing a significant risk of polio re-emergence. A new type 2 OPV (nOPV2), with promising clinical data on genetic stability and immunogenicity, recently received authorization from the World Health Organization for use in response to circulating, vaccine-derived poliovirus outbreaks. Here we report the development of two additional live attenuated vaccine candidates against type 1 and 3 polioviruses. The candidates were generated by replacing the capsid coding region of nOPV2 with that from Sabin 1 or 3. These chimeric viruses show growth phenotypes similar to nOPV2 and immunogenicity comparable to their parental Sabin strains, but are more attenuated. Our experiments in mice and deep sequencing analysis confirmed that the candidates remain attenuated and preserve all the documented nOPV2 characteristics concerning genetic stability following accelerated virus evolution. Importantly, these vaccine candidates are highly immunogenic in mice as monovalent and multivalent formulations and may contribute to poliovirus eradication.
Topics: Animals; Mice; Disease Models, Animal; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; Vaccines, Attenuated; Disease Eradication
PubMed: 37316671
DOI: 10.1038/s41586-023-06212-3