PARIS—Shares in biotech company Valneva fell again on Wednesday, declining for the seventh day in a row due to a growing belief amongst investors that the COVID-19 Omicron variant might lessen the need for mass vaccination. At 0945 GMT, Valneva shares were down 3 percent at 17.10 euros, meaning the stock has now lost close to 40 percent since its Dec. 27 close of 26.38 euros. It did gain more than 200 percent a year in 2021 and 2020 as Valneva’s COVID-19 vaccine candidate came increasingly closer to approval. It is still awaiting a green light for its shot in the European Union and Britain. “The decline of the share price seems to be mostly driven by retail investors who think that there will be no need of a new vaccination campaign after the Omicron wave”, a Paris-based analyst said. Companies whose COVID-19 vaccines have already been approved have also …