I en sekundær undersøgelse af uønskede hændelser (Adverse Event Monitoring Substudy) fik en undergruppe af patienter fra SPS- undersøgelsen (n=3345 modtog ZOSTAVAX og n=3271 modtog placebo) udleveret vaccinationsindberetningskort til registrering af uønskede reaktioner, der forekom fra dag 0 til dag 42 efter vaccination; disse patienter blev desuden overvåget rutinemæssigt mht. sikkerhed.
In the Adverse Event Monitoring Substudy, a subgroup of individuals from the SPS (n=3345 received ZOSTAVAX and n=3271 received placebo) were provided vaccination report cards to record adverse reactions occurring from Days 0 to 42 postvaccination in addition to undergoing routine safety monitoring throughout the study.