-
The Pan African Medical Journal 2023Polio is an infectious and disabling life-threatening disease caused by the poliovirus. This disease is prevented through vaccination. Though this viral infection has...
Polio is an infectious and disabling life-threatening disease caused by the poliovirus. This disease is prevented through vaccination. Though this viral infection has been eliminated in most parts of the world, a few countries are still endemic to wild poliovirus. In 2020, the World Health Organization (WHO) African Region, including Cameroon, was certified free of wild poliovirus. Some countries recurrently report circulating vaccine-derived poliovirus cases (cVDPV) despite recorded achievements. Also, the risk of importing poliovirus from endemic settings remains, particularly in the context of coronavirus disease (COVID-19). This study aimed to assess the state of polio in Cameroon and identify the situation during COVID-19. A data review was conducted from February to March 2023. Data on polio cases and vaccination coverage per region of Cameroon were reviewed from 2014 to 2022. Data were analyzed with Microsoft Excel, and the results were presented as proportions. The last wild poliovirus was reported in Cameroon in 2014, and the country benefitted from a response. No case of poliovirus was detected in the country from 2015 to 2018. After that, an increasing number of type two cVDPV were reported across 50% of the country's regions from 2019 to 2022. The outbreaks benefitted from responses with various oral polio vaccines, including the type two novel oral polio vaccine (nOPV-2). Though wild polioviruses have been eliminated in most countries, including Cameroon, cVDPV remains a significant problem. There is an urgent need to strengthen disease surveillance and vaccination to prevent cVDPV-2 in this country, particularly in the COVID-19 context.
Topics: Humans; Cameroon; Pandemics; COVID-19; Poliomyelitis; Poliovirus; Disease Outbreaks; Poliovirus Vaccine, Oral; Blindness
PubMed: 37663631
DOI: 10.11604/pamj.2023.45.90.35332 -
BMC Infectious Diseases May 2017The international spread of wild poliomyelitis outbreaks continues to threaten eradication of poliomyelitis and in 2014 a public health emergency of international...
BACKGROUND
The international spread of wild poliomyelitis outbreaks continues to threaten eradication of poliomyelitis and in 2014 a public health emergency of international concern was declared. Here we describe a risk scoring system that has been used to assess country-level risks of wild poliomyelitis outbreaks, to inform prioritisation of mass vaccination planning, and describe the change in risk from 2014 to 2016. The methods were also used to assess the risk of emergence of vaccine-derived poliomyelitis outbreaks.
METHODS
Potential explanatory variables were tested against the reported outbreaks of wild poliomyelitis since 2003 using multivariable regression analysis. The regression analysis was translated to a risk score and used to classify countries as Low, Medium, Medium High and High risk, based on the predictive ability of the score.
RESULTS
Indicators of population immunity, population displacement and diarrhoeal disease were associated with an increased risk of both wild and vaccine-derived outbreaks. High migration from countries with wild cases was associated with wild outbreaks. High birth numbers were associated with an increased risk of vaccine-derived outbreaks.
CONCLUSIONS
Use of the scoring system is a transparent and rapid approach to assess country risk of wild and vaccine-derived poliomyelitis outbreaks. Since 2008 there has been a steep reduction in the number of wild poliomyelitis outbreaks and the reduction in countries classified as High and Medium High risk has reflected this. The risk of vaccine-derived poliomyelitis outbreaks has varied geographically. These findings highlight that many countries remain susceptible to poliomyelitis outbreaks and maintenance or improvement in routine immunisation is vital.
Topics: Africa; Asia; Disease Outbreaks; Humans; Mass Vaccination; Poliomyelitis; Poliovirus; Poliovirus Vaccines; Public Health; Risk Assessment; Spatio-Temporal Analysis
PubMed: 28549485
DOI: 10.1186/s12879-017-2443-4 -
The Journal of Infectious Diseases Nov 2014To strengthen the Nigeria polio eradication program at the operational level, the National Stop Transmission of Polio (N-STOP) program was established in July 2012 as a... (Review)
Review
To strengthen the Nigeria polio eradication program at the operational level, the National Stop Transmission of Polio (N-STOP) program was established in July 2012 as a collaborative effort of the National Primary Health Care Development Agency, the Nigerian Field Epidemiology and Laboratory Training Program, and the US Centers for Disease Control and Prevention. Since its inception, N-STOP has recruited and trained 125 full-time staff, 50 residents in training, and 50 ad hoc officers. N-STOP officers, working at national, state, and district levels, have conducted enumeration outreaches in 46,437 nomadic and hard-to-reach settlements in 253 districts of 19 states, supported supplementary immunization activities in 236 districts, and strengthened routine immunization in 100 districts. Officers have also conducted surveillance assessments, outbreak response, and applied research as needs evolved. The N-STOP program has successfully enhanced Global Polio Eradication Initiative partnerships and outreach in Nigeria, providing an accessible, flexible, and culturally competent technical workforce at the front lines of public health. N-STOP will continue to respond to polio eradication program needs and remain a model for other healthcare initiatives in Nigeria and elsewhere.
Topics: Centers for Disease Control and Prevention, U.S.; Disease Eradication; Epidemiological Monitoring; Health Policy; Humans; International Cooperation; Nigeria; Poliomyelitis; Poliovirus Vaccines; United States
PubMed: 25316824
DOI: 10.1093/infdis/jiu199 -
PLoS Pathogens Jun 2015
Review
Topics: History, 20th Century; History, 21st Century; Poliomyelitis; Poliovirus; Virus Replication
PubMed: 26042673
DOI: 10.1371/journal.ppat.1004825 -
Vaccine Aug 2017The European Region, certified polio-free in 2002, remains at risk of wild poliovirus reintroduction and emergence of circulating vaccine-derived polioviruses (cVDPV)... (Review)
Review
BACKGROUND
The European Region, certified polio-free in 2002, remains at risk of wild poliovirus reintroduction and emergence of circulating vaccine-derived polioviruses (cVDPV) until global polio eradication is achieved, as demonstrated by the cVDPV1 outbreak in Ukraine in 2015.
METHODS
We reviewed epidemiologic, clinical and virology data on cVDPV cases, surveillance and immunization coverage data, and reports of outbreak-related surveys, country missions, and expert group meetings.
RESULTS
In Ukraine, 3-dose polio vaccine coverage declined from 91% in 2008 to 15% by mid-2015. In summer, 2015, two unrelated children from Zakarpattya province were paralyzed by a highly divergent cVDPV1. The isolates were 20 and 26 nucleotide divergent from prototype Sabin strain (with 18 identical mutations) consistent with their common origin and ∼2-year evolution. Outbreak response recommendations developed with international partner support included conducting three nationwide supplementary immunization activities (SIAs) with tOPV, strengthening surveillance and implementing communication interventions. SIAs were conducted during October 2015-February 2016 (officially reported coverage, round 1-64.4%, round 2-71.7%, and round 3-80.7%). Substantial challenges to outbreak response included lack of high-level support, resistance to OPV use, low perceived risk of polio, widespread vaccine hesitancy, anti-vaccine media environment, economic crisis and military conflict. Communication activities improved caregiver awareness of polio and confidence in vaccination. Surveillance was enhanced but did not consistently meet applicable performance standards. Post-outbreak assessments concluded that cVDPV1 transmission in Ukraine has likely stopped following the response, but significant gaps in population immunity and surveillance remained.
CONCLUSIONS
Chronic under-vaccination in Ukraine resulted in the accumulation of children susceptible to polioviruses and created favorable conditions for VDPV1 emergence and circulation, leading to the outbreak. Until programmatic gaps in immunization and surveillance are addressed, Ukraine will remain at high-risk for VDPV emergence and circulation, as well as at risk for other vaccine-preventable diseases.
Topics: Adolescent; Child; Disease Eradication; Disease Outbreaks; Female; Humans; Infant; Male; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; Poliovirus Vaccines; Ukraine; Vaccination; Vaccination Refusal
PubMed: 28528761
DOI: 10.1016/j.vaccine.2017.04.036 -
Medecine Tropicale Et Sante... Jun 2021In 2019, the Central African Republic identified foci of circulating vaccine-derived poliovirus 2 (PVDV2c). The objective of this work is to describe the vaccination...
OBJECTIVE
In 2019, the Central African Republic identified foci of circulating vaccine-derived poliovirus 2 (PVDV2c). The objective of this work is to describe the vaccination status of children paralyzed by PVDV2c and their contacts and to assess the circulation of this strain in these contacts.
PATIENTS AND METHOD
The study population of this retrospective survey consists of children with acute flaccid paralysis (AFP) and their contacts. We included paralyzed children whose sequencing results showed the presence of PVDV2c.
RESULTS
A total of 21 children paralyzed by PVDVc and 64 contacts were enrolled in the survey. Fourteen out of 21 children who are paralyzed (66%) received at least one dose of bivalent oral polio vaccine (OPV) compared to 36 out of 64 contacts (57%, non-significant difference). Of the vaccinated patients, 7 had received less than three doses. For the injectable polio vaccine (IPV), vaccination coverage for both patients and contacts was 33%.The proportion of children who received both doses of OPV and IPV was 33% among patients and 25% in contacts. Contacts with VDPV2 were vaccinated with OPV and IPV, respectively 55 and 27%. VDPV2 and Sabin 2 were also found in contact stools, 34% and 9% respectively.
CONCLUSION
The absence or inadequacy of IPV vaccination has a serious impact on children by the occurrence of virus derived from the vaccine responsible for life-old paralysis. Protecting children from poliomyelitis requires a combination of a good cold chain, multiple doses and adherence to the vaccine schedule.
Topics: Central African Republic; Child; Humans; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; Poliovirus Vaccines; Retrospective Studies
PubMed: 35586583
DOI: 10.48327/mtsibulletin.2021.114 -
Praxis Feb 2023
Topics: Humans; Disease Progression; Poliomyelitis
PubMed: 36722102
DOI: 10.1024/1661-8157/a003987 -
MMWR. Morbidity and Mortality Weekly... Apr 2022Since the Global Polio Eradication Initiative (GPEI) was established in 1988, the number of reported poliomyelitis cases worldwide has declined by approximately 99.99%....
Since the Global Polio Eradication Initiative (GPEI) was established in 1988, the number of reported poliomyelitis cases worldwide has declined by approximately 99.99%. By the end of 2021, wild poliovirus (WPV) remained endemic in only two countries (Pakistan and Afghanistan). However, a WPV type 1 (WPV1) case with paralysis onset in 2021, was reported by Malawi a year after the World Health Organization (WHO) African Region (AFR) was certified as WPV-free and circulating vaccine-derived poliovirus (cVDPV) cases were reported from 31 countries during 2020-2021 (1,2). cVDPVs are oral poliovirus vaccine-derived viruses that can emerge after prolonged circulation in populations with low immunity and cause paralysis. The primary means of detecting poliovirus transmission is through surveillance for acute flaccid paralysis (AFP) among persons aged <15 years, with confirmation through stool specimen testing by WHO-accredited laboratories, supplemented by systematic sampling of sewage and testing for the presence of poliovirus (environmental surveillance). The COVID-19 pandemic caused disruptions in polio vaccination and surveillance activities across WHO regions in 2020; during January-September 2020, the number of reported cases of AFP declined and the interval between stool collection and receipt by laboratories increased compared with the same period in 2019 (3). This report summarizes surveillance performance indicators for 2020 and 2021 in 43 priority countries* and updates previous reports (4). In 2021, a total of 32 (74%) priority countries met two key surveillance performance indicator targets nationally, an improvement from 2020 when only 23 (53%) met both targets; however, substantial national and subnational gaps persist. High-performing poliovirus surveillance is critical to tracking poliovirus transmission. Frequent monitoring of surveillance indicators could help identify gaps, guide improvements, and enhance the overall sensitivity and timelines of poliovirus detection to successfully achieve polio eradication.
Topics: Humans; COVID-19; Disease Eradication; Global Health; Immunization Programs; Pandemics; Paralysis; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; Population Surveillance
PubMed: 35421079
DOI: 10.15585/mmwr.mm7115a2 -
Expert Review of Vaccines Nov 2022Multiple vaccine options are available for polio prevention and risk management. Integrated global risk, economic, and poliovirus transmission modeling provides a tool...
BACKGROUND
Multiple vaccine options are available for polio prevention and risk management. Integrated global risk, economic, and poliovirus transmission modeling provides a tool to explore the dynamics of ending all use of one or more poliovirus vaccines to simplify the polio eradication endgame.
RESEARCH DESIGN AND METHODS
With global reported cases of poliomyelitis trending higher since 2016, we apply an integrated global model to simulate prospective vaccine policies and strategies for OPV-using countries starting with initial conditions that correspond to the epidemiological poliovirus transmission situation at the beginning of 2022.
RESULTS
Abruptly ending all OPV use in 2023 and relying only on IPV to prevent paralysis with current routine immunization coverage would lead to expected reestablished endemic transmission of poliovirus types 1 and 2, and approximately 150,000 expected cases of poliomyelitis per year. Alternatively, if OPV-using countries restart trivalent OPV (tOPV) use for all immunization activities and end IPV use, the model shows the lowest anticipated annual polio cases and lowest costs.
CONCLUSIONS
Poor global risk management and coordination of OPV cessation remain a critical failure mode for the polio endgame, and national and global decision makers face difficult choices due to multiple available polio vaccine options and immunization strategies.
Topics: Humans; Poliovirus Vaccine, Oral; Poliovirus Vaccine, Inactivated; Disease Eradication; Global Health; Poliomyelitis; Poliovirus
PubMed: 36154436
DOI: 10.1080/14760584.2022.2128108 -
Journal of Clinical Microbiology Feb 2018With poliovirus eradication nearing, few pockets of active wild poliovirus (WPV) transmission remain in the world. Intratypic differentiation (ITD) plays a crucial part...
With poliovirus eradication nearing, few pockets of active wild poliovirus (WPV) transmission remain in the world. Intratypic differentiation (ITD) plays a crucial part in laboratory surveillance as the molecular detection method that can identify and distinguish wild and vaccine-like polioviruses isolated from acute flaccid paralysis cases or environmental sources. The need to detect new variants of WPV serotype 1 (WPV1) and the containment of all serotype 2 polioviruses (PV2) in 2015 required changes to the previous version of the method. The ITD version 5.0 is a set of six real-time reverse transcription-PCR (rRT-PCR) assays that serve as accurate diagnostic tools to easily detect and differentiate PV serotypes and genotypes. We describe the creation and properties of quantitation standards, including 16 control RNA transcripts and nine plaque-isolated viruses. All ITD rRT-PCR assays were validated using these standards, and the limits of detection were determined for each assay. We designed and pilot tested two new assays targeting recently circulating WPV1 genotypes and all PV2 viruses. The WPV1 assay had 99.1% specificity and 100% sensitivity, and the PV2 assay had 97.7% specificity and 92% sensitivity. Before proceeding to the next step in the global poliovirus eradication program, we needed to gain a better understanding of the performance of the ITD 5.0 suite of molecular assays and their limits of detection and specificities. The findings and conclusions in this evaluation serve as building blocks for future development work.
Topics: Disease Eradication; Epidemiological Monitoring; Genotype; Humans; Molecular Typing; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; RNA, Viral; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction; Sensitivity and Specificity; Serogroup
PubMed: 29212703
DOI: 10.1128/JCM.01624-17