Shares of Novavax surged as much as 23% in premarket trading Wednesday after the company announced that an early stage clinical trial of its COVID-19 vaccine produced promising results.

The trial included 131 healthy adults between 18 and 59, and was conducted across two sites in Australia, the company said. Novavax’s COVID-19 vaccine, NVX‑CoV2373, “was generally well-tolerated and elicited robust antibody responses,” the company said Tuesday.

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The vaccine produced neutralizing antibodies in all patients that received it with mild side effects, the study found. Those who received two shots of the vaccine plus a shot of adjuvant, an ingredient designed to boost immune response, had neutralizing antibody levels that were roughly four times higher than those seen in a group of patients who had recovered from COVID-19.

Novavax is one of many companies including Pfizer and Moderna that are racing to produce a COVID-19 vaccine.

Shares of Novavax have surged more than 4,700% year-to-date.

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Foto: Source: Markets Insider