Apparently China waited months before reporting a vaccine revertant poliovirus:
13 Jul 2019 China: Vaccine-Derived Type 2 Polio
(not secure)
outbreaknewstoday.com/china-reports-polio-case-from-sichuan-province-pakistan-records-9-more-wpv1-cases-88868/
'....on April 25....'
13 Jul 2019 China: Vaccine-Derived Type 2 Polio
(not secure)
outbreaknewstoday.com/china-reports-polio-case-from-sichuan-province-pakistan-records-9-more-wpv1-cases-88868/
'....on April 25....'