Safety monitoring
ADVERSE EVENTS, EVENTS, ADVERSE REACTIONS, MISCARRIAGE
Participants were observed for 30 minutes after each vaccination for the occurrence of any immediate reactions. All the participants were trained to record any solicited and unsolicited adverse events, medication administration, and other vaccinations occurred within 30 days after vaccination on the diary card distributed. Serious adverse events (SAEs) occurring within the 66-month study period were collected regularly by safety assessors. Adverse reactions, defined as adverse events related to vaccination, were judged by investigators with physician qualification according to the implementation rules, as described previously [All the participants in the trial should have negative urine pregnancy test results before each vaccination and were requested to avoid pregnancy within eight months after the first dose. Women with a positive test result should be suspended the vaccination and may continue two weeks after the end of pregnancy (delivery or miscarriage). All pregnancy events during the study period were recorded in detail through periodic telephone or in-person investigations. For pregnant women planning to deliver, regular telephone follow-up should be conducted at least once every three months. The last telephone survey should be conducted one month after the end of delivery.