Kapusinszky 2010.

Methods	Study design: nationwide uncontrolled before‐and‐after study Setting: Hungary National AFP surveillance data from 1992 to 2006. Type 3 polioviruses isolated from the stools of patients with onset of AFP were recovered from archived specimens at the National Institute of Public Health, Budapest, Hungary. Study dates: 1959 to 1992
Participants	Participants: Out of all vaccinated Hungarian children, 90 cases of vaccine‐associated paralytic poliomyelitis (VAPP) were reported, 52 of which were associated with Sabin 3‐related virus (76% of VAPP cases with virologic data). Age: range = 1 to 54 months (mean = 15.6 months, median = 9 months)
Interventions	Before (from 1959 to 1992, duration 396 months) O: (mOPV1, mOPV2, mOPV3) separated by 6 weeks at age 2‐38 months After (from 1992 to 2006, duration 168 months) IOOOOO: IPV at 3 months, 5 tOPV
Outcomes	Frequency of the VAPP cases and the molecular characterization of these poliovirus isolates, reported at any time during the follow‐up Follow‐up: 15 years
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Blinding of participants and personnel (performance bias) All outcomes	Low risk
Blinding of outcome assessment (detection bias) All outcomes	Low risk
ITS/UBA: blinded assessment of primary outcome(s)	Unclear risk	Comment: AFP and virological testing are objective outcomes; however, VAPP requires interpretation.
ITS/UBA: reliable primary outcome measure(s)	Low risk	Comment: In Hungary, the surveillance of AFP continued permanently with high standards. Additianalyy, there was a molecular characterization of poliovirus isolates from children who contracted VAPP.
UBA: follow‐up of professionals	Low risk	Comment: national AFP surveillance suggests a complete nationwide follow‐up. The follow‐up period was long enough.
UBA: follow‐up of patients	Low risk	Comment: national AFP surveillance suggests a complete nationwide follow‐up. The follow‐up period was long enough.
Conflict of interest	Unclear risk	Comment: supported by the RiViGene Project (Genomic inventory, forensic markers, and assessment of potential therapeutic and vaccine targets for viruses relevant in biological crime and terrorism; Contract number: SSPE‐CT‐2005‐022639)