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Aims: The bivalent oral poliovirus vaccine (bOPV; Sabin types 1 and 3) replaced the trivalent OPV (Sabin types 1, 2 and 3) globally in April 2016. A routine schedule of 1 dose of inactivated poliovirus vaccine and 3 subsequent doses of bOPV was implemented in Jiangsu simultaneously. The schedule was changed to 2 inactivated poliovirus vaccines + 2 bOPV on 1 September 2019. Although OPV type 2 has been removed, challenges persist because of adverse events following immunization (AEFIs) with bOPV. Therefore, we analysed and evaluated the safety profile of bOPV administered in children based on passive postmarketing AEFI surveillance. Methods: We collected all bOPV‐related AEFI reports in Jiangsu from the Chinese National AEFI Information System (CNAEFIS) between May 2016 and April 2020. We obtained the administered doses of bOPV from the Jiangsu Provincial Electronic Immunization Registries System. A descriptive analysis was performed. Results: In total, 2084 bOPV‐related AEFIs were retrieved from the CNAEFIS. The overall reporting rate was 24.16 per 100 000 doses. Most AEFIs were nonserious. The most frequently reported symptoms were fever, rash and gastrointestinal disorders. Only 1.34% of AEFIs were serious, which thrombocytopenic purpura accounted for the largest category. Seventeen serious adverse events, including 2 vaccine‐associated paralytic poliomyelitis (VAPP) cases, were considered to be related to bOPV vaccination. The rate of VAPP was 0.2 per million doses. Conclusion: AEFI analysis showed that bOPV was well tolerated. The events most frequently reported were nonserious. However, bOPV can still cause VAPP. Attention should be given to risks related to bOPV. [ABSTRACT FROM AUTHOR]

Polytetrafluoroethylene (PTFE) porous hollow-fiber membranes were prepared by a method involving billet preform, paste extrusion, stretching, and sintering. The influence of stretching parameters including stretching ratio, temperature, and speed was systematically investigated. The structure and properties of these membranes were characterized by field emission scanning electron microscopy, filtration performance, and mechanical strength test. The results indicate that the stretching ratio is the most significant influencing factor for the formation of various regions in the stress-strain curve. With increasing stretching ratio, the porosity, maximum pore size, and ethanol flux increase remarkably while bovine serum albumin rejection is reduced. These findings have the potential to facilitate PTFE membrane fabrication with finely tuned microporous structure for various application processes. [ABSTRACT FROM AUTHOR]