sIPV	Sabin strain–based inactivated poliovirus vaccine
IPV	Inactivated poliovirus vaccine
OPV	Oral poliovirus vaccine
DTaP	Diphtheria–tetanus–acellular pertussis vaccine
DT	Diphtheria–tetanus vaccine
Hib	Haemophilus influenzae type b vaccine
MMR	Measles–mumps–rubella vaccine
BCG	Bacille Calmette–Guérin vaccine
EV71	Enterovirus 71 vaccine
VAPP	Vaccine-associated paralytic poliomyelitis
VDPV	Vaccine-derived poliovirus
AEFI	Adverse events following immunization
CNAEFIS	China National Adverse Events Following Immunization Surveillance System
WHO	World Health Organization
GPEI	Global Polio Eradication Initiative
RR	Relative risk
aRR	Adjusted rate ratio
CI	Confidence interval
NB	Negative binomial (regression)
NHC	National Health Commission of China
NMPA	National Medical Products Administration
CDC	Center for Disease Control and Prevention