PARIS - French biotech firm Valneva said on Friday that no conclusions should be drawn on the effectiveness of its COVID-19 vaccine candidate, known as VLA2001, from a new British study on booster shots.
The study said COVID-19 vaccines made by Pfizer and Moderna that use mRNA technology provide the biggest boost to antibody levels when given 10-12 weeks after the second dose.
Traders cited the study as the reason behind a fall of up to 24% in Valneva's shares on Friday.
"The setting in this study leads us to believe that COV-Boost does not allow any conclusions to be reached regarding the use of VLA2001 as a booster in a real-life setting," Valneva said in an e-mailed statement in response to a Reuters query.
"Valneva believes it is likely that the short interval between the second shot and booster shot could have adversely impacted the results for VLA2001, given that a longer interval is generally required for inactivated vaccines."