Poliomyelitis, or polio, is a highly infectious disease and can result in permanent flaccid paralysis of the limbs. Singapore was certified polio-free by the World Health Organization (WHO) on 29 October 2000, together with 36 other countries in the Western Pacific Region. The last imported case of polio in Singapore was in 2006. Fortunately, polio is vaccine-preventable-the world saw the global eradication of wild poliovirus types 2 and 3 achieved in 2015 and 2019, respectively. However, in late 2022, a resurgence of paralytic polio cases from vaccine-derived poliovirus (VDPV) was detected in countries like Israel and the US (specifically, New York); VDPV was also detected during routine sewage water surveillance with no paralysis cases in London, UK. Without global eradication, there is a risk of re-infection from importation and spread of wild poliovirus or VDPV, or new emergence and circulation of VDPV. During the COVID-19 pandemic, worldwide routine childhood vaccination coverage fell by 5% to 81% in 2020-2021. Fortunately, Singapore has maintained a constantly high vaccination coverage of 96% among 1-year-old children as recorded in 2021. All countries must ensure high poliovirus vaccination coverage in their population to eradicate poliovirus globally, and appropriate interventions must be taken to rectify this if the coverage falters. In 2020, WHO approved the emergency use listing of a novel oral polio vaccine type 2 for countries experiencing circulating VDPV type 2 outbreaks. Environmental and wastewater surveillance should be implemented to allow early detection of "silent" poliovirus transmission in the population, instead of relying on clinical surveillance of acute flaccid paralysis based on case definition alone.
Child ; Humans ; Infant ; Public Health Surveillance ; Pandemics ; Wastewater ; Wastewater-Based Epidemiological Monitoring ; COVID-19/epidemiology* ; Poliomyelitis/prevention & control* ; Poliovirus ; Poliovirus Vaccine, Oral ; Vaccination ; Global Health

The eradication of poliomyelitis is a landmark achievement in the history of public health, providing strong protection for children's health. The introduction of the Chinese Regulations for the Manufacture and Control of Live Poliovirus Vaccine is a prerequisite and safeguard for the large-scale production and use of domestically produced live poliovirus vaccines, serving as an indispensable component of vaccine safety. This article, based on archival documents, letters, collections of essays, and oral interviews, examines the historical experience of the development of Chinese Regulations for the Manufacture and Control of Live Poliovirus Vaccine. It contends that the emphasis on localization and the active engagement in international cooperation are critical factors in the swift introduction of Chinese Regulations for the Manufacture and Control of Live Poliovirus Vaccine.
Child ; Humans ; Poliovirus Vaccine, Inactivated ; Poliomyelitis/epidemiology* ; Disease Outbreaks ; China

OBJECTIVES: Investigations into the epidemiology of acute flaccid paralysis (AFP) are an essential strategic component of the Global Poliomyelitis Eradication Initiative of the World Health Organization (WHO), and are part of the certification process for polio eradication worldwide. This is an epidemiological report of AFP incidence in children less than 15 years old in southwest Iran. METHODS: This was a retrospective cohort study, carried out based on WHO guidelines, in which we reviewed non-polio AFP cases recorded from January 2006 to December 2010 in different regions of Khuzestan Province, southwest Iran. In this study, the records of all children under 15 years old with AFP were evaluated. RESULTS: During a 5-year period, 137 cases of AFP were reported (incidence rate, 2.21 per 100,00 children <15 years old). More than 50% (73 of 137) of the cases were boys, and 52.6% (72 of 137) were under 5 years of age, with a mean age of 5.39±3.98 years. The incidence of AFP was significantly higher in older children (p=0.001). The most common cause of paralysis was Guillain-Barré syndrome (117 of 137). None of the cases were diagnosed with acute poliomyelitis. CONCLUSIONS: In this study, we found that the incidence rate of AFP in the region was almost in agreement with the expected incidence of AFP in children less than 15 years old; therefore, the AFP surveillance program in Khuzestan Province is satisfactory in terms of reliability and effectiveness. Nevertheless, routine vaccination against polio and ensuring that patients with AFP receive follow-up are essential for eradicating polio.
Certification ; Child ; Cohort Studies ; Epidemiology ; Follow-Up Studies ; Guillain-Barre Syndrome ; Humans ; Incidence ; Iran* ; Paralysis* ; Poliomyelitis ; Retrospective Studies ; Vaccination ; World Health Organization

INTRODUCTIONThis study reviewed the epidemiological trends of poliomyelitis from 1946 to 2010, and the impact of the national immunisation programme in raising the population herd immunity against poliovirus. We also traced the efforts Singapore has made to achieve certification of poliomyelitis eradication by the World Health Organisation.

MATERIALS AND METHODSEpidemiological data on all reported cases of poliomyelitis were obtained from the Communicable Diseases Division of the Ministry of Health as well as historical records. Coverage of the childhood immunisation programme against poliomyelitis was based on the immunisation data maintained by the National Immunisation Registry, Health Promotion Board. To assess the herd immunity of the population against poliovirus, 6 serological surveys were conducted in 1962, 1978, 1982 to 1984, 1989, 1993 and from 2008 to 2010.

RESULTSSingapore was among the fi rst countries in the world to introduce live oral poliovirus vaccine (OPV) on a mass scale in 1958. With the comprehensive coverage of the national childhood immunisation programme, the incidence of paralytic poliomyelitis declined from 74 cases in 1963 to 5 cases from 1971 to 1973. The immunisation coverage for infants, preschool and primary school children has been maintained at 92% to 97% over the past decade. No indigenous poliomyelitis case had been reported since 1978 and all cases reported subsequently were imported.

CONCLUSIONSingapore was certified poliomyelitis free along with the rest of the Western Pacific Region in 2000 after fulfilling all criteria for poliomyelitis eradication, including the establishment of a robust acute flaccid paralysis surveillance system. However, post-certification challenges remain, with the risk of wild poliovirus importation. Furthermore, it is timely to consider the replacement of OPV with the inactivated poliovirus vaccine in Singapore's national immunisation programme given the risk of vaccine-associated paralytic poliomyelitis and circulating vaccine-derived polioviruses.

Adolescent ; Certification ; Child ; Child, Preschool ; Disease Eradication ; organization & administration ; Female ; Humans ; Infant ; Male ; Poliomyelitis ; epidemiology ; prevention & control ; virology ; Poliovirus ; immunology ; Singapore ; epidemiology

To find out epidemiological feature of paralytic cases caused by type 2 vaccine-derived poliovirus (VDPV) and the excretion status of the case and to explore the enterovirus infection status among healthy children under five years old around the case in Zhaotong city, Yunnan Province in 2010. Field epidemiological studies at the epidemic area were conducted and a total of 108 stool samples were collected, three from the case, seven from the close contacts and 98 from the healthy children. VDPV was not isolated again from the case; Sabin-like PV strains or VDPV were not isolated from the close contacts and the healthy children; An active search for acute flaccid paralysis cases was conducted in the area, which indicated that the VDPV did not cause virus circulation in local area. Twenty one (20.0%) NPEVs were isolated from 105 stool samples. Among the 21 NPEV isolates, 11 isolates (52.4%) were HEV-A (3 serotypes), 10 isolates (47.6%) were HEV-B (4 serotypes).
Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Male ; Phylogeny ; Poliomyelitis ; epidemiology ; etiology ; Poliovirus ; classification ; isolation & purification ; Poliovirus Vaccines ; adverse effects

Background: Trivalent poliomyelitis vaccine was produced from strains which had been supported by Japan. One of the standards of vaccine quality required by WHO is potency and thermostability. Follow that potency at 370C and within 48 hours is not less effective than potency at -200C exceedingly 0,5 lgCCID50. Objectives: To assess the potency of Trivalent poliomyelitis vaccine and the thermostability of mokey vaccine preserved at 370C within 48 hours. Subjects and method: 12 lots of trivalent poliomyelitis vaccine (included 3 types) produced in January 2007 were evaluated by microneutralization technique. Results: Potency of 12 type I lots were all 106,0 CCID50/0,1ml and the disparity of potency at two temperatures were all < 0,5 lgCCID50/0,1ml. Potency of 12 type II lots were all 105,0 CCID50/0,1ml and the disparity of potency at two temperatures were all < 0,5 lgCCID50/0,1ml. Potency of 12 type III lots were all 105,5 CCID50/0,1ml and the disparity of potency at two temperatures were all < 0,5 lgCCID50/0,1ml. Conclusion: 12 final poliovaccine lots produced in Center for research and production of vaccines and biologicals \ufffd?Ha Noi in 2007 met WHO requirements for potency and thermostability.
Poliomyelitis ; Nonpoliovirus ; Poliovirus Vaccines/ therapeutic use ; Oliomyelitis/ immunology ; epidemiology

OBJECTIVETo analyze the event and cause of vaccine derived polio virus (VDPV) circle happened at Yaoshang Village, Wanlan Township, Zhenfeng County, Qianxinan Prefecture, Guizhou Province in August 2004.

METHODSVirus isolation was performed for stool specimens collected from two children cases with acute flaccid paralysis (AFP) reported at Yaoshang Village and 21 normal children under five years old in the same village. And, routine immunization coverage at the Village and AFP incidence and performance of AFP surveillance system in Zhenfeng County were investigated, as well.

RESULTSVaccine derived polio virus 1 (VDPV1) was identified in the feces of two affected children at Yaoshang Village and three other normal children at the same village. Totally, seven cases of AFP have been underreported in Zhenfeng County since 2002. Routine immunization coverage was rather low at Wanlan Township, and nearly nil at Yaoshang Village.

CONCLUSIONSOral polio vaccine (OPV) with attenuated live virus has been used in China for many years to prevent polio. Circulation of VDPV in Zhenfeng County issues a new challenge to eradication of polio. It is necessary to strengthen routine immunization and AFP surveillance to prevent occurrence of VDPV event.

Child, Preschool ; China ; epidemiology ; Feces ; virology ; Humans ; Incidence ; Infant ; Male ; Poliomyelitis ; epidemiology ; transmission ; virology ; Poliovirus ; immunology ; isolation & purification ; Poliovirus Vaccine, Inactivated ; adverse effects ; Poliovirus Vaccine, Oral ; adverse effects

OBJECTIVETo study the circulating vaccine-derived poliovirus (cVDPVs) that occurred in Zhenfeng county, Guizhou province in 2004 and to discover wild-poliovirus, vaccine-derived poliovirus (VDPVs) and other vaccine-associated poliovirus which could cause clinical poliomyelitis.

METHODSField epidemiological studies at the epidemic area and collecting acute flaccid paralysis (AFP) case and contact stool specimen for virus identification and nucleotide sequencing. Analysis on data related to annual reports on stool specimens surveillance which involved AFP case and contacts in the resent years in Zhenfeng county.

RESULTSType-I VDPVs had been isolated from 2 AFP cases and 3 contact stool specimen in Wanlan village of Zhenfeng. After the first cVDPVs case was identified, there were 3 cases identified of having other vaccine-associated poliovirus of type-I or type-II in the 5 case of AFP that met the criteria of clinical poliomyelitis. The result of virological surveillance on polio showed that the EV isolation rate (55.1%) of Zhenfeng county was higher than the rate from the whole province of the same year (23.2%). The poliovirus (PV) isolation rate (36.8%) was obviously higher in 2004 than in the previous years. In the 16 PVs strains, the type-I accounted for 43.8% which was significantly higher than the average level (18.3%) from the whole province.

CONCLUSIONSData indicated that the type-I VDPVs had been circulating (cVDPVs) in Zhenfeng county in Guizhou province. Clinical poliomyelitis was caused by non-VDPVs. The increased PV infection and the decreasing rate of vaccination in the general population were responsible for the epidemic of type-I cVDPVs at this time. Monitoring and evaluation on the rate of routine immunization program and prediction of the trend of epidemic should be strenthened.

Adolescent ; Animals ; Cell Line ; Child, Preschool ; China ; epidemiology ; Disease Outbreaks ; Feces ; virology ; Humans ; Infant ; Infant, Newborn ; Male ; Paraplegia ; epidemiology ; etiology ; virology ; Poliomyelitis ; prevention & control ; Poliovirus ; immunology ; physiology ; Poliovirus Vaccines ; immunology ; Vaccination ; statistics & numerical data

The rate of immunization was high and maintained continuously 11 years in the Northern Region. Evident, efficacy is the decreasing of incidence of EPI diseases, especially poliomyelitis, neonatal tetanus, and diphtheria. During continuous 8 years (from 1994 to 2001), there has been no wild poliovirus in the Northern Region, and the Region was certificated as polio-free in 2000. Neonatal tetanus has also been eliminated at the provincial level since 1995 and at district level since 1999. The other EPI diseases have been considerably reduced
Epidemiology ; immunization ; poliomyelitis ; Tetanus ; Diphtheria

The serology epidemiological investigation on 2-10 years old children in 3 geographic areas of Thanh Hoa province after immunized by oral OPV vaccine showed a rate of protective antibody of 76.5% to all 3 types. There is no difference in the rate of children having protective antibody to type 1 and 2 but type 3 in these 3 areas. A difference of GMT among children in 3 geographic areas, and the last level is in Yen Dinh district. GMT to each polio virus type was higher than the protective immunity level (>8)
Poliomyelitis ; Child ; Diseases ; epidemiology ; Poliovirus Vaccine, Oral