GlaxoSmithKline (GSK) and Canada-based Medicago announced that their experimental COVID-19 vaccine induced antibody levels 10 times higher than those seen in patients after recovery from the disease.

The companies reported interim phase 2 study results showing Medicago’s plant-based vaccine combined with GSK’s adjuvant produced similar immune responses across all ages with no serious adverse events.

The vaccine entered a phase 3 study in March to evaluate a two-dose regimen in up to 30,000 participants. Enrollment began in U.S., Canada, the UK and Brazil, but is expected to include up to 10 countries.

The vaccine candidate has received FDA Fast-Track designation and is being assessed by Health Canada under a rolling review.