What happened

Shares of Dynavax Technologies (DVAX -1.82%) are on the move after the company's vaccine adjuvant was featured in a positive clinical trial readout. Investors excited about the results have pushed the biotech stock 26.6% higher as of 12:02 p.m. EDT on Wednesday. 

So what 

Today, Dynavax's collaboration partner, Clover Biopharmaceuticals, reported positive results from the pivotal Spectra trial with Clover's COVID-19 vaccine candidate, SCB-2019. This is a protein-based vaccine that employs a booster, or adjuvant, from Dynavax. 

Happy person raises hands in triumph.

Image source: Getty Images.

The Spectra trial enrolled over 30,000 adults in five countries spread across four continents. Clearly, delta and other variants of concern had already taken over when the trial enrolled volunteers. None of those who tested positive were infected with the original virus responsible for COVID-19.

Against the delta variant, SCB-2019 was 79% effective against COVID-19 of any severity. The stock would have risen much further, but overall efficacy was only 67% against COVID-19 infection of any variety.

Now what

Dynavax investors shouldn't be too disappointed with the relatively low overall efficacy rate. The more established vaccines from Moderna and Pfizer were tested before today's variants of concern had taken over. 

The Spectra trial with SCB-2019 is sponsored by the Coalition for Epidemic Preparedness Innovations, or CEPI. This is one of the entities behind the Covax initiative to expand vaccine access worldwide. 

There's a good chance that Covax will pick up what Dynavax and Clover are putting down. None of the volunteers randomized to receive SCB-2019 were hospitalized or died from any COVID-19 variant.