Vaccine efficacy was calculated as 1 minus the hazard ratio for HIV-1 infection, which was estimated using a sex-stratified Cox proportional-hazards (Cox PH) model and tested using a sex-stratified log-rank test. Vaccine efficacy was also measured using a ratio of cumulative incidences (CIR) of HIV-1 infection in the vaccine group as compared with the placebo group, which was calculated using Nelson-Aalen cumulative hazard estimates and tested using a Wald test.

Graded according to the Division of AIDS (DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events, Version 2.1 \[July 2017\]. The maximum grade observed for each symptom over the time frame is presented.

Graded according to the Division of AIDS (DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events, Version 2.1 \[July 2017\]. The maximum grade observed for each symptom over the time frame is presented.

Graded according to the Division of AIDS (DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events, Version 2.1 \[July 2017\]. The maximum grade observed for each symptom over the time frame is presented.

For participants reporting multiple AEs over the time frame, the maximum relationship is counted.

For participants reporting multiple AEs over the time frame, the maximum severity grade is counted.

Measured as outlined in Version 2.0 (January 2010) of the Manual for Expedited Reporting of Adverse Events to DAIDS (DAIDS EAE Manual).

Adverse events of special interest (AESI) were described in Appendix J of the protocol. AESI for this protocol include but are not limited to potential immune-mediated diseases.

A new chronic medical condition is defined as a new onset or exacerbation of medical condition requiring 2 or more visits to a medical provider during a period of at least 30 days.

From the termination form, early study termination associated with an AE or reactogenicity reasons are tabulated by treatment group.

From the study product discontinuation form, study product discontinuation reasons are tabulated by treatment group.

Per the 23 January 2020 DSMB finding that monitoring boundaries for non-efficacy have been met, Primary outcome 1 has been superseded by this primary outcome. Vaccine efficacy was calculated as 1 minus the hazard ratio for HIV-1 infection, which was estimated using a sex-stratified Cox proportional-hazards (Cox PH) model and tested using a sex-stratified log-rank test. Vaccine efficacy was also measured using a ratio of cumulative incidences (CIR) of HIV-1 infection in the vaccine group as compared with the placebo group, which was calculated using Nelson-Aalen cumulative hazard estimates and tested using a Wald test.

Serum IgG responses were measured on a Bio-Plex instrument using a standardized custom Luminex assay, run at 1:50 dilution. The readout is background-subtracted mean fluorescent intensity (MFI), with background adjustment for an antigen-specific plate level control. For each sample, response magnitude is net MFI, defined as experimental antigen MFI minus reference antigen MFI. Net MFI \< 1 is set to 1, and net MFI \> 22,000 is set to 22,000. Data are excluded if blood draw date was outside the allowable window, a participant was HIV-infected, reference antigen \> 5,000 MFI, or baseline net MFI \> 6,500. Samples from post-enrollment visits have positive responses if they meet three criteria: (1) net MFI greater than or equal to an antigen-specific response threshold (defined as the maximum of 100 and the 95th percentile of baseline net MFI), (2) net MFI values are greater than 3 times baseline net MFI, and (3) experimental antigen MFI values are greater than 3 times baseline MFI.

Serum IgG responses were measured on a Bio-Plex instrument using a standardized custom Luminex assay, run at 1:50 dilution. The readout is background-subtracted mean fluorescent intensity (MFI), with background adjustment for an antigen-specific plate level control. For each sample, response magnitude is net MFI, defined as experimental antigen MFI minus reference antigen MFI. Net MFI \< 1 is set to 1, and net MFI \> 22,000 is set to 22,000. Data are excluded if blood draw date was outside the allowable window, a participant was HIV-infected, reference antigen \> 5,000 MFI, or baseline net MFI \> 6,500. Comparisons were performed among positive responders only (positivity criteria are described in Outcome 1).

Serum IgA responses were measured on a Bio-Plex instrument using a standardized custom Luminex assay, run at 1:10 dilution. The readout is background-subtracted mean fluorescent intensity (MFI), with background adjustment for an antigen-specific plate level control. For each sample, response magnitude is net MFI, defined as experimental antigen MFI minus reference antigen MFI. Net MFI \< 1 is set to 1, and net MFI \> 22,000 is set to 22,000. Data are excluded if blood draw date was outside the allowable window, a participant was HIV-infected, reference antigen \> 5,000 MFI, or baseline net MFI \> 6,500. Samples from post-enrollment visits have positive responses if they meet three criteria: (1) net MFI greater than or equal to an antigen-specific response threshold (defined as the maximum of 100 and the 95th percentile of baseline net MFI), (2) net MFI values are greater than 3 times baseline net MFI, and (3) experimental antigen MFI values are greater than 3 times baseline MFI.

Serum IgA responses were measured on a Bio-Plex instrument using a standardized custom Luminex assay, run at 1:10 dilution. The readout is background-subtracted mean fluorescent intensity (MFI), with background adjustment for an antigen-specific plate level control. For each sample, response magnitude is net MFI, defined as experimental antigen MFI minus reference antigen MFI. Net MFI \< 1 is set to 1, and net MFI \> 22,000 is set to 22,000. Data are excluded if blood draw date was outside the allowable window, a participant was HIV-infected, reference antigen \> 5,000 MFI, or baseline net MFI \> 6,500. Comparisons were performed among positive responders only (positivity criteria are described in Outcome 1).

New chronic conditions are adverse events that require medical intervention for \>= 30 days.

For each local laboratory measure, summary statistics were presented by treatment group and timepoint for the overall population.

For each local laboratory measure, summary statistics were presented by treatment group and timepoint for the overall population.

For each local laboratory measure, summary statistics were presented by treatment group and timepoint for the overall population.

For each local laboratory measure, summary statistics were presented by treatment group and timepoint for the overall population.

For each local laboratory measure, summary statistics were presented by treatment group and timepoint for the overall population.

The number (percentage) of participants with local laboratory values recorded as meeting Grade 1 AE criteria or above as specified in the DAIDS AE Grading Table were tabulated by treatment arm for each post-vaccination time point.