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1.
MMWR Morb Mortal Wkly Rep ; 72(23): 613-620, 2023 Jun 09.
Article in English | MEDLINE | ID: covidwho-20243279

ABSTRACT

Since the Global Polio Eradication Initiative (GPEI) was established in 1988, the number of wild poliovirus (WPV) cases has declined by >99.9%, and WPV serotypes 2 and 3 have been declared eradicated (1). By the end of 2022, WPV type 1 (WPV1) transmission remained endemic only in Afghanistan and Pakistan (2,3). However, during 2021-2022, Malawi and Mozambique reported nine WPV1 cases that were genetically linked to Pakistan (4,5), and circulating vaccine-derived poliovirus (cVDPV) outbreaks were detected in 42 countries (6). cVDPVs are oral poliovirus vaccine-derived viruses that can emerge after prolonged circulation in populations with low immunity allowing reversion to neurovirulence and can cause paralysis. Polioviruses are detected primarily through surveillance for acute flaccid paralysis (AFP), and poliovirus is confirmed through stool specimen testing. Environmental surveillance, the systematic sampling of sewage and testing for the presence of poliovirus, supplements AFP surveillance. Both surveillance systems were affected by the COVID-19 pandemic's effects on public health activities during 2020 (7,8) but improved in 2021 (9). This report updates previous reports (7,9) to describe surveillance performance during 2021-2022 in 34 priority countries.* In 2022, a total of 26 (76.5%) priority countries met the two key AFP surveillance performance indicator targets nationally compared with 24 (70.6%) countries in 2021; however, substantial gaps remain in subnational areas. Environmental surveillance expanded to 725 sites in priority countries, a 31.1% increase from the 553 sites reported in 2021. High-quality surveillance is critical to rapidly detect poliovirus transmission and enable prompt poliovirus outbreak response to stop circulation. Frequent monitoring of surveillance guides improvements to achieve progress toward polio eradication.


Subject(s)
COVID-19 , Enterovirus , Poliomyelitis , Poliovirus , Humans , Pandemics , alpha-Fetoproteins , Disease Eradication , Population Surveillance , Global Health , COVID-19/epidemiology , Poliomyelitis/epidemiology , Poliomyelitis/prevention & control , Poliomyelitis/diagnosis , Poliovirus/genetics , Poliovirus Vaccine, Oral , Disease Outbreaks/prevention & control , Immunization Programs
2.
MMWR Morb Mortal Wkly Rep ; 71(49): 1541-1546, 2022 Dec 09.
Article in English | MEDLINE | ID: covidwho-2272481

ABSTRACT

Afghanistan and Pakistan are the two remaining countries with endemic wild poliovirus type 1 (WPV1) transmission (1). During 2019-2020, these countries reported their highest numbers of WPV1 cases since 2014 and experienced outbreaks of type 2 circulating vaccine-derived poliovirus (cVDPV2) (2-4).* In Afghanistan, the number of WPV1 cases nearly doubled, from 29 in 2019 to 56 in 2020; 308 cVDPV2 cases were reported during 2020. After years of active conflict, the Afghanistan government was fully replaced by the Taliban de facto government on August 15, 2021. This report describes activities and progress toward polio eradication in Afghanistan during January 2021-September 2022 and updates previous reports (3,4). During January-December 2021, four WPV1 and 43 cVDPV2 cases were detected, representing decreases of 93% from 56 cases and 86% from 308 cases, respectively, during 2020. During January-September 2022 (reported as of October 20), two WPV1 cases and zero cVDPV2 cases were detected. Although no supplementary immunization activities (SIAs)† occurred during July-October 2021, SIAs resumed during November 2021 in all districts after the political transition, and 3.5-4.5 million previously unreachable persons have been vaccinated since. However, restrictions on how SIAs are conducted are still in place in the critical South Region provinces of Kandahar, Helmand, and Uruzgan. If efforts to vaccinate all children are enhanced and expanded, Afghanistan has an opportunity to interrupt WPV1 transmission during 2023.


Subject(s)
Child , Humans , Afghanistan/epidemiology , Pakistan
3.
MMWR Morb Mortal Wkly Rep ; 72(14): 366-371, 2023 Apr 07.
Article in English | MEDLINE | ID: covidwho-2252235

ABSTRACT

Circulating vaccine-derived poliovirus (cVDPV) outbreaks* can occur when oral poliovirus vaccine (OPV, containing one or more Sabin-strain serotypes 1, 2, and 3) strains undergo prolonged circulation in under-vaccinated populations, resulting in genetically reverted neurovirulent virus (1,2). Following declaration of the eradication of wild poliovirus type 2 in 2015 and the global synchronized switch from trivalent OPV (tOPV, containing Sabin-strain types 1, 2, and 3) to bivalent OPV (bOPV, containing types 1 and 3 only) for routine immunization activities† in April 2016 (3), cVDPV type 2 (cVDPV2) outbreaks have been reported worldwide (4). During 2016-2020, immunization responses to cVDPV2 outbreaks required use of Sabin-strain monovalent OPV2, but new VDPV2 emergences could occur if campaigns did not reach a sufficiently high proportion of children. Novel oral poliovirus vaccine type 2 (nOPV2), a more genetically stable vaccine than Sabin OPV2, was developed to address the risk for reversion to neurovirulence and became available in 2021. Because of the predominant use of nOPV2 during the reporting period, supply replenishment has frequently been insufficient for prompt response campaigns (5). This report describes global cVDPV outbreaks during January 2021-December 2022 (as of February 14, 2023) and updates previous reports (4). During 2021-2022, there were 88 active cVDPV outbreaks, including 76 (86%) caused by cVDPV2. cVDPV outbreaks affected 46 countries, 17 (37%) of which reported their first post-switch cVDPV2 outbreak. The total number of paralytic cVDPV cases during 2020-2022 decreased by 36%, from 1,117 to 715; however, the proportion of all cVDPV cases that were caused by cVDPV type 1 (cVDPV1) increased from 3% in 2020 to 18% in 2022, including the occurrence of cocirculating cVDPV1 and cVDPV2 outbreaks in two countries. The increased proportion of cVDPV1 cases follows a substantial decrease in global routine immunization coverage and suspension of preventive immunization campaigns during the COVID-19 pandemic (2020-2022) (6); outbreak responses in some countries were also suboptimal. Improving routine immunization coverage, strengthening poliovirus surveillance, and conducting timely and high-quality supplementary immunization activities (SIAs) in response to cVDPV outbreaks are needed to interrupt cVDPV transmission and reach the goal of no cVDPV isolations in 2024.


Subject(s)
Disease Outbreaks , Poliomyelitis , Poliovirus Vaccine, Oral , Child , Humans , Poliomyelitis/epidemiology , Poliomyelitis/prevention & control , Poliovirus/genetics , Poliovirus Vaccine, Oral/adverse effects
4.
Vaccine ; 41 Suppl 1: A48-A57, 2023 04 06.
Article in English | MEDLINE | ID: covidwho-2243472

ABSTRACT

After six years without any detection of poliomyelitis cases, Angola reported a case of circulating vaccine-derived poliovirus type 2 (cVDPV2) with paralysis onset date of 27 March 2019. Ultimately, 141 cVDPV2 polio cases were reported in all 18 provinces in 2019-2020, with particularly large hotspots in the south-central provinces of Luanda, Cuanza Sul, and Huambo. Most cases were reported from August to December 2019, with a peak of 15 cases in October 2019. These cases were classified into five distinct genetic emergences (emergence groups) and have ties with cases identified in 2017-2018 in the Democratic Republic of Congo. From June 2019 to July 2020, the Angola Ministry of Health and partners conducted 30 supplementary immunization activity (SIA) rounds as part of 10 campaign groups, using monovalent OPV type 2 (mOPV2). There were Sabin 2 vaccine strain detections in the environmental (sewage) samples taken after mOPV2 SIAs in each province. Following the initial response, additional cVDPV2 polio cases occurred in other provinces. However, the national surveillance system did not detect any new cVDPV2 polio cases after 9 February 2020. While reporting subpar indicator performance in epidemiological surveillance, the laboratory and environmental data as of May 2021 strongly suggest that Angola successfully interrupted transmission of cVDPV2 early in 2020. Additionally, the COVID-19 pandemic did not allow a formal Outbreak Response Assessment (OBRA). Improving the sensitivity of the surveillance system and the completeness of AFP case investigations will be vital to promptly detect and interrupt viral transmission if a new case or sewage isolate are identified in Angola or central Africa.


Subject(s)
COVID-19 , Poliomyelitis , Poliovirus , Humans , Sewage , Angola/epidemiology , Pandemics , COVID-19/epidemiology , Poliomyelitis/prevention & control , Poliovirus Vaccine, Oral/adverse effects , Disease Outbreaks/prevention & control
5.
MMWR Morb Mortal Wkly Rep ; 71(33): 1065-1068, 2022 Aug 19.
Article in English | MEDLINE | ID: covidwho-1994638

ABSTRACT

On July 18, 2022, the New York State Department of Health (NYSDOH) notified CDC of detection of poliovirus type 2 in stool specimens from an unvaccinated immunocompetent young adult from Rockland County, New York, who was experiencing acute flaccid weakness. The patient initially experienced fever, neck stiffness, gastrointestinal symptoms, and limb weakness. The patient was hospitalized with possible acute flaccid myelitis (AFM). Vaccine-derived poliovirus type 2 (VDPV2) was detected in stool specimens obtained on days 11 and 12 after initial symptom onset. To date, related Sabin-like type 2 polioviruses have been detected in wastewater* in the patient's county of residence and in neighboring Orange County up to 25 days before (from samples originally collected for SARS-CoV-2 wastewater monitoring) and 41 days after the patient's symptom onset. The last U.S. case of polio caused by wild poliovirus occurred in 1979, and the World Health Organization Region of the Americas was declared polio-free in 1994. This report describes the second identification of community transmission of poliovirus in the United States since 1979; the previous instance, in 2005, was a type 1 VDPV (1). The occurrence of this case, combined with the identification of poliovirus in wastewater in neighboring Orange County, underscores the importance of maintaining high vaccination coverage to prevent paralytic polio in persons of all ages.


Subject(s)
COVID-19 , Poliomyelitis , Poliovirus Vaccine, Oral , Poliovirus , Humans , New York/epidemiology , Poliomyelitis/epidemiology , Poliomyelitis/prevention & control , Poliovirus Vaccine, Oral/adverse effects , Public Health , SARS-CoV-2 , Wastewater
6.
MMWR Morb Mortal Wkly Rep ; 71(15): 538-544, 2022 Apr 15.
Article in English | MEDLINE | ID: covidwho-1789730

ABSTRACT

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.


Subject(s)
COVID-19 , Poliomyelitis , Poliovirus , Disease Eradication , Global Health , Humans , Immunization Programs , Pandemics , Paralysis/epidemiology , Poliomyelitis/diagnosis , Poliomyelitis/epidemiology , Poliomyelitis/prevention & control , Poliovirus Vaccine, Oral , Population Surveillance , alpha-Fetoproteins
7.
MMWR Morb Mortal Wkly Rep ; 71(3): 85-89, 2022 Jan 21.
Article in English | MEDLINE | ID: covidwho-1637158

ABSTRACT

Wild poliovirus types 2 and 3 were declared eradicated in 2015 and 2019, respectively, and, since 2017, transmission of wild poliovirus type 1 (WPV1) has been detected only in Afghanistan and Pakistan. In 2020, these countries reported their highest number of WPV1 cases since 2014 and experienced outbreaks of type 2 circulating vaccine-derived poliovirus (cVDPV2)* (1); in Afghanistan, the number of WPV1 cases reported increased 93%, from 29 in 2019 to 56 in 2020, with 308 cVDPV2 cases reported. This report describes the activities and progress toward polio eradication in Afghanistan during January 2020-November 2021 and updates previous reports (2-4). Despite restrictions imposed by antigovernment elements since 2018, disruption of polio eradication efforts by the COVID-19 pandemic, and civil and political instability, eradication activities have resumed. During January-November 2021, four WPV1 cases and 43 cVDPV2 cases were detected, representing decreases of 93% from 56 and 85% from 281, respectively, during the same period in 2020. After the assumption of nationwide control by the current de facto government of Afghanistan during August 2021, health officials committed to oral poliovirus vaccine (OPV) campaigns nationwide, with the potential to vaccinate approximately 2.5 million children against poliovirus who were previously not accessible for ≥2 years. Although challenges remain, vigorous, sustained polio eradication efforts in Afghanistan could result in substantial progress toward eradication during 2022-2023.


Subject(s)
Disease Eradication , Immunization Programs , Poliomyelitis/epidemiology , Poliomyelitis/prevention & control , Population Surveillance , Adult , Afghanistan/epidemiology , Child , Child, Preschool , Disease Outbreaks/prevention & control , Humans , Infant , Poliovirus/isolation & purification , Poliovirus Vaccine, Oral/administration & dosage
8.
MMWR Morb Mortal Wkly Rep ; 70(39): 1359-1364, 2021 Oct 01.
Article in English | MEDLINE | ID: covidwho-1444552

ABSTRACT

When the Global Polio Eradication Initiative began in 1988, wild poliovirus (WPV) transmission was occurring in 125 countries; currently, only WPV type 1 (WPV1) transmission continues, and as of August 2021, WPV1 transmission persists in only two countries (1,2). This report describes Pakistan's progress toward polio eradication during January 2020-July 2021 and updates previous reports (3,4). In 2020, Pakistan reported 84 WPV1 cases, a 43% reduction from 2019; as of August 25, 2021, Pakistan has reported one WPV1 case in 2021. Circulating vaccine-derived poliovirus (cVDPV) emerges as a result of attenuated oral poliovirus vaccine (OPV) virus regaining neurovirulence after prolonged circulation in underimmunized populations and can lead to paralysis. In 2019, 22 cases of cVDPV type 2 (cVDPV2) were reported in Pakistan, 135 cases were reported in 2020, and eight cases have been reported as of August 25, 2021. Because of the COVID-19 pandemic, planned supplementary immunization activities (SIAs)* were suspended during mid-March-June 2020 (3,5). Seven SIAs were implemented during July 2020-July 2021 without substantial decreases in SIA quality. Improving the quality of polio SIAs, vaccinating immigrants from Afghanistan, and implementing changes to enhance program accountability and performance would help the Pakistan polio program achieve its goal of interrupting WPV1 transmission by the end of 2022.


Subject(s)
Disease Eradication , Poliomyelitis/prevention & control , Population Surveillance , Adolescent , Child , Child, Preschool , Humans , Immunization Programs , Immunization Schedule , Infant , Pakistan/epidemiology , Poliomyelitis/epidemiology , Poliovirus/isolation & purification , Poliovirus Vaccine, Oral/administration & dosage , Vaccination/statistics & numerical data
9.
MMWR Morb Mortal Wkly Rep ; 70(18): 667-673, 2021 May 07.
Article in English | MEDLINE | ID: covidwho-1218743

ABSTRACT

When the Global Polio Eradication Initiative (GPEI) was established in 1988, an estimated 350,000 poliomyelitis cases were reported worldwide. In 2020, 140 wild poliovirus (WPV) cases were confirmed, representing a 99.99% reduction since 1988. WPV type 1 transmission remains endemic in only two countries (Pakistan and Afghanistan), but outbreaks of circulating vaccine-derived poliovirus (cVDPV) occurred in 33 countries during 2019-2020 (1,2). Poliovirus transmission is detected primarily through syndromic surveillance for acute flaccid paralysis (AFP) among children aged <15 years, with confirmation by laboratory testing of stool specimens. Environmental surveillance supplements AFP surveillance and plays an increasingly important role in detecting poliovirus transmission. Within 2 weeks of COVID-19 being declared a global pandemic (3), GPEI recommended continuing surveillance activities with caution and paused all polio supplementary immunization activities (4). This report summarizes surveillance performance indicators for 2019 and 2020 in 42 priority countries at high risk for poliovirus transmission and updates previous reports (5). In 2020, 48% of priority countries* in the African Region, 90% in the Eastern Mediterranean Region, and 40% in other regions met AFP surveillance performance indicators nationally. The number of priority countries rose from 40 in 2019 to 42 in 2020.† Analysis of 2019-2020 AFP surveillance data from 42 countries at high risk for poliovirus transmission indicates that national and subnational nonpolio AFP rates and stool specimen adequacy declined in many priority countries, particularly in the African Region, suggesting a decline in surveillance sensitivity and quality. The findings in this report can be used to guide improvements to restore a sensitive surveillance system that can track poliovirus transmission and provide evidence of interruption of transmission.


Subject(s)
Disease Eradication , Global Health/statistics & numerical data , Poliomyelitis/prevention & control , Population Surveillance , Humans , Poliomyelitis/epidemiology
10.
MMWR Morb Mortal Wkly Rep ; 69(46): 1748-1752, 2020 Nov 20.
Article in English | MEDLINE | ID: covidwho-937754

ABSTRACT

Pakistan and Afghanistan are the only countries where wild poliovirus type 1 (WPV1) is endemic (1,2). In 2019, Pakistan reported 147 WPV1 cases, approximately 12 times the number reported in 2018. As of September 15, 72 cases had been reported in 2020. Since 2019, WPV1 transmission has also spread from Pakistan's core poliovirus reservoirs (Karachi, Peshawar, and Quetta block) to southern districts of Khyber Pakhtunkhwa (KP), Punjab, and Sindh provinces. Further, an outbreak of circulating vaccine-derived poliovirus type 2 (cVDPV2), first detected in July 2019, has caused 22 paralytic cases in 2019 and 59 as of September 15, 2020, throughout the country. The coronavirus disease 2019 (COVID-19) pandemic has substantially reduced delivery of polio vaccines through essential immunization (formerly routine immunization) and prevented implementation of polio supplementary immunization activities (SIAs)* during March-July 2020. This report describes Pakistan's progress in polio eradication during January 2019-September 2020 and updates previous reports (1,3,4). The Pakistan polio program has reinitiated SIAs and will need large, intensive, high-quality campaigns with strategic use of available oral poliovirus vaccines (OPVs)† to control the surge and widespread transmission of WPV1 and cVDPV2.


Subject(s)
Disease Eradication , Poliomyelitis/prevention & control , Population Surveillance , Adolescent , Child , Child, Preschool , Humans , Immunization Schedule , Infant , Pakistan/epidemiology , Poliomyelitis/epidemiology , Poliovirus Vaccines/administration & dosage , Vaccination/statistics & numerical data
11.
MMWR Morb Mortal Wkly Rep ; 69(40): 1464-1468, 2020 Oct 09.
Article in English | MEDLINE | ID: covidwho-842550

ABSTRACT

Wild poliovirus type 1 (WPV1) transmission is ongoing only in Afghanistan and Pakistan (1). Following a decline in case numbers during 2013-2016, the number of cases in Afghanistan has increased each year during 2017-2020. This report describes polio eradication activities and progress toward polio eradication in Afghanistan during January 2019-July 2020 and updates previous reports (2,3). Since April 2018, insurgent groups have imposed bans on house-to-house vaccination. In September 2019, vaccination campaigns in areas under insurgency control were restarted only at health facilities. In addition, during March-June 2020, all campaigns were paused because of the coronavirus disease 2019 (COVID-19) pandemic. The number of WPV1 cases reported in Afghanistan increased from 21 in 2018 to 29 in 2019. During January-July 2020, 41 WPV1 cases were reported as of August 29, 2020 (compared with 15 during January-July 2019); in addition, 69 cases of circulating vaccine-derived poliovirus type 2 (cVDPV2), and one case of ambiguous vaccine-derived poliovirus type 2 (aVDPV2) (isolates with no evidence of person-to-person transmission or from persons with no known immunodeficiency) were detected. Dialogue with insurgency leaders through nongovernmental and international organizations is ongoing in an effort to recommence house-to-house campaigns, which are essential to stopping WPV1 transmission in Afghanistan. To increase community demand for polio vaccination, additional community health needs should be addressed, and polio vaccination should be integrated with humanitarian services.


Subject(s)
Disease Eradication , Poliomyelitis/prevention & control , Population Surveillance , Adolescent , Afghanistan/epidemiology , Child , Child, Preschool , Humans , Immunization Programs , Immunization Schedule , Infant , Poliomyelitis/epidemiology , Poliovirus/isolation & purification , Poliovirus Vaccine, Oral/administration & dosage , Vaccination/statistics & numerical data
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