An Outbreak of Type Π Vaccine-Derived Poliovirus in Sichuan Province, China: Emergence and Circulation in an Under-Immunized Population
نویسندگان
چکیده
BACKGROUND During August 2011-February 2012, an outbreak of type Π circulating vaccine-derived poliovirus (cVDPVs) occurred in Sichuan Province, China. METHODS A field investigation of the outbreak was conducted to characterize outbreak isolates and to guide emergency response. Sequence analysis of poliovirus capsid protein VP1 was performed to determine the viral propagation, and a coverage survey was carried out for risk assessment. RESULTS One clinical compatible polio case and three VDPV cases were determined in Ngawa County, Ngawa Tibetan and Qiang Autonomous Prefecture, Sichuan Province. Case patients were unimmunized children, 0.8-1 years old. Genetic sequencing showed that the isolates diverged from the VP1 region of the type Π Sabin strain by 5-12 nucleotides (nt) and shared the same 5 nt VP1 substitutions, which indicate single lineage of cVDPVs. Of the 7 acute flaccid paralysis cases (all>6 months) reported in Ngawa Prefecture in 2011, 4 (57.1%) cases (including 2 polio cases) did not receive oral attenuated poliovirus vaccine. Supplementary immunization activities (SIAs) were conducted in February-May, 2012, and the strain has not been isolated since. CONCLUSION High coverage of routine immunization should be maintained among children until WPV transmission is globally eradicated. Risk assessments should be conducted regularly to pinpoint high risk areas or subpopulations, with SIAs developed if necessary.
منابع مشابه
Alarm of Circulating Wild Poliovirus and Of Vaccine-Derived Poliovirus in Middle East Countries as a Potential Risk for Re-Emerging of Polio in Iran
Poliomyelitis is a highly infectious viral disease which is mainly transmitted via contaminated food and drinking water by human feces, especially in situations of poor hygiene and sanitation (1). This disease is caused by 3 types of wild poliovirus (WPV) (types 1, 2 and 3), and immunity against one type does not create immunity against other types. In our country according National Immuni...
متن کاملVaccine-Derived Poliovirus Outbreaks and Events — Three Provinces, Democratic Republic of the Congo, 2017
The last confirmed wild poliovirus (WPV) case in Democratic Republic of the Congo (DRC) had paralysis onset in December 2011 (1). DRC has had cases of vaccine-derived polioviruses (VDPVs) documented since 2004 (Table 1) (1-6). After an outbreak of 30 circulating VDPV type 2 (cVDPV2) cases during 2011-2012, only five VDPV2 cases were reported during 2013-2016 (Table 1) (1-6). VDPVs can emerge fr...
متن کاملLimited and localized outbreak of newly emergent type 2 vaccine-derived poliovirus in Sichuan, China.
From August 2011 to February 2012, an outbreak caused by type 2 circulating vaccine-derived poliovirus (cVDPV) occurred in Aba County, Sichuan, China. During the outbreak, four type 2 VDPVs (≥0.6% nucleotide divergence in the VP1 region relative to the Sabin 2 strain) were isolated from 3 patients with acute flaccid paralysis (AFP) and one close contact. In addition, a type 2 pre-VDPV (0.3% to ...
متن کاملOutbreak of Type 2 Vaccine-Derived Poliovirus in Nigeria: Emergence and Widespread Circulation in an Underimmunized Population
Wild poliovirus has remained endemic in northern Nigeria because of low coverage achieved in the routine immunization program and in supplementary immunization activities (SIAs). An outbreak of infection involving 315 cases of type 2 circulating vaccine-derived poliovirus (cVDPV2; >1% divergent from Sabin 2) occurred during July 2005-June 2010, a period when 23 of 34 SIAs used monovalent or biv...
متن کاملReemergence of recombinant vaccine-derived poliovirus outbreak in Madagascar.
BACKGROUND After the 2001-2002 poliomyelitis outbreak due to recombinant vaccine-derived polioviruses (VDPVs) in the Toliara province of Madagascar, another outbreak reoccurred in the same province in 2005. METHODS We conducted epidemiological and virological investigations for each polio case patient and for their contacts. RESULTS From May to August 2005, a total of 5 cases of acute flacc...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 9 شماره
صفحات -
تاریخ انتشار 2014