drug ineffective; covid-19; break through bleeding; this is a spontaneous report received from a contactable reporter(s) (consumer or other non hcp) from the regulatory authority-web and product quality group. regulatory number: nl-lrb-00737609. a 42 year-old female patient received bnt162b2 (comirnaty), administration date 02aug2021 (lot number: ff0688) at the age of 42 years as dose 2, 0.3 ml single and administration date 15jun2021 (lot number: unknown) as dose 1, 0.3 ml single for covid-19 immunisation. the patient's relevant medical history and concomitant medications were not reported. the following information was reported: drug ineffective (medically significant) with onset 18nov2021, outcome "unknown", described as "drug ineffective"; covid-19 (medically significant) with onset 18nov2021, outcome "unknown", described as "covid-19"; intermenstrual bleeding (non-serious) with onset 02aug2021, outcome "not recovered", described as "break through bleeding". the patient underwent the following laboratory tests and procedures: sars-cov-2 test positive: (18nov2021) positive. no follow-up attempts are possible; information about lot/batch number cannot be obtained. no further information is expected