Study of AZD1222 for the Prevention of COVID-19 in Japan

Seroresponse is a binary outcome where a success is when the fold rise in titers compared with baseline is >= 4. The fold rise in titers was calculated as the ratio of the post-vaccination titer level to the baseline titer level. The percentage of participants with a post-vaccination seroresponse (>= 4-fold rise in titers from Day 1 baseline value to Day 57) to the S antigen of AZD1222 as measured by MSD serology assay is reported.

Solicited AEs are local or systemic predefined AEs for reactogenicity assessment. Participants were given an axillary thermometer, tape measure, and access to app for the solicited AE eDiary, with instructions on use, along with the emergency 24-hour telephone number to contact the on-call study physician if needed. Participants were instructed to record for 7 days following administration of each dose of AZD1222, the timing and severity of local and systemic solicited AEs, if applicable, and whether medication was taken to relieve the symptoms.

Solicited AEs are local or systemic predefined AEs for reactogenicity assessment. Participants were given an axillary thermometer, tape measure, and access to app for the solicited AE eDiary, with instructions on use, along with the emergency 24-hour telephone number to contact the on-call study physician if needed. Participants were instructed to record for 7 days following administration of each dose of AZD1222, the timing and severity of local and systemic solicited AEs, if applicable, and whether medication was taken to relieve the symptoms.

An AE is the development of any untoward medical occurrence in a clinical study participant administered medicinal product and which does not necessarily have a causal relationship with this medicinal product. An AE can therefore be any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. An SAE is an AE occurring during any study phase that fulfils one or more of the following criteria: death; immediately life-threatening; in-participant hospitalization or prolongation of existing hospitalization; persistent or significant disability or incapacity; congenital abnormality or birth defect; an important medical event. The AESIs were events of scientific and medical interest specific to the further understanding of the study vaccination safety profile and required close monitoring and rapid communication by the investigators to the sponsor.

Clinical laboratory values were evaluated for each laboratory parameter as applicable including hematology and clinical chemistry. The baseline was defined as the last non-missing measurement taken prior to the first dose of study vaccination (including unscheduled measurements, if any).

Seroresponse is a binary outcome where a success is when the fold rise in titers compared with baseline is >= 4. The fold rise in titers was calculated as the ratio of the post-vaccination titer level to the baseline titer level. The percentage of participants with a post-vaccination seroresponse (>= 4-fold rise in titers from Day 1 baseline value to Day 57) to the RBD antigen of AZD1222 as measured by MSD serology assay is reported.

The GMT was calculated as the antilogarithm of Σ(log base 2 transformed titer/n), i.e. as the anti-logarithm transformation of the mean of the log-transformed titer, where 'n' is the number of participants with titer information.

The fold rise was calculated as the ratio of the post-vaccination titer level to the baseline titer level, where baseline was defined as the last measurement taken before the first dose of study vaccination. The GMFR was calculated as anti-logarithm of Σ (log base 2 transformed (post-vaccination titer/ pre-vaccination titer)/n). Where 'n' is the number of participants with titer information.

Seroresponse is a binary outcome where a success is when the fold rise in titers compared with baseline is >= 4. The fold rise in titers was calculated as the ratio of the post-vaccination titer level to the baseline titer level. The percentage of participants with a post-vaccination seroresponse (>= 4-fold rise in titers from Day 1 baseline value to Day 57) to SARS-CoV-2 nAb of AZD1222 as measured by pseudo-neutralization assay is reported.

The GMT was calculated as the antilogarithm of Σ(log base 2 transformed titer/n), i.e. as the anti-logarithm transformation of the mean of the log-transformed titer, where 'n' is the number of participants with titer information.

The fold rise was calculated as the ratio of the post-vaccination titer level to the baseline titer level, where baseline was defined as the last measurement taken before the first dose of study vaccination. The GMFR was calculated as anti-logarithm of Σ (log base 2 transformed (post-vaccination titer/ pre-vaccination titer)/n). Where 'n' is the number of participants with titer information.

An SAE is an AE occurring during any study phase that fulfils one or more of the following criteria: death; immediately life-threatening; in-participant hospitalization or prolongation of existing hospitalization; persistent or significant disability or incapacity; congenital abnormality or birth defect; an important medical event. The AESIs were events of scientific and medical interest specific to the further understanding of the study vaccination safety profile and required close monitoring and rapid communication by the investigators to the sponsor.