ImmunityBio and NantKwest have reported that their COVID-19 vaccine candidate induced neutralizing antibodies and T-cell responses against both the SARS-CoV-2 spike protein and the nucleocapsid proteins that surround the core structure of the virus.

There were no serious adverse events in the low-dose arm of the phase 1 study, the companies said. But the vaccine’s safety is still being assessed in the high-dose cohort.

The early-stage trial at Hoag Hospital in Newport Beach, Calif., included just 20 volunteers.

Based on the promising early results, the companies plan to launch late-stage trials that will include volunteers previously infected with SARS-CoV-2.