Shares of CureVac NV dropped more than 50% in the extended session Wednesday after the German biotech company said its COVID-19 vaccine candidate is 47% effective in preventing the disease.
messenger RNA-based vaccine would compete with similarly designed vaccines from Pfizer Inc
as well as Moderna Inc.
which have shown efficacy above 90% and have already been given to millions of people worldwide.
CureVac said that its “pivotal” study, conducted in 10 countries and involving about 40,000 people, showed the vaccine candidate’s being a poor match against a “fast changing environment” of at least 29 COVID-19 variants, with the original coronavirus strain “almost completely absent.”
Moreover, initial scrutiny of the vaccine candidate’s efficacy showed it to be likely dependent on a person’s age and on which strain they contract, the company said. CureVac is continuing toward a final analysis of some 80 additional cases, and the overall vaccine efficacy could change, it said.
“While we were hoping for a stronger interim outcome, we recognize that demonstrating high efficacy in this unprecedented broad diversity of variants is challenging,” Chief Executive Franz-Werner Haas said in a statement.
“In addition, the variant-rich environment underlines the importance of developing next-generation vaccines as new virus variants continue to emerge,” he said.
Earlier this week, Novavax Inc.
said its vaccine candidate against COVID-19 was 90% effective in preventing the disease.
Some 146 million people in the U.S. have been fully vaccinated against COVID, or about 43% of the population, but the vaccination rates in several other countries are lower and many poorer countries struggle to provide enough vaccines for their residents.
More than 3.8 million people around the world have died of COVID-19, including more than 600,000 in the U.S., which surpassed that 600,000 level on Tuesday.
Variants, some more contagious, more lethal, or both, have emerged in several countries.
On Tuesday, the U.S. Centers for Disease Control and Prevention reclassified the Delta variant of COVID-19, first emerging in India, to one “of concern,” from a less concerning designation of “of interest.”
Other “of concern” variants include the Alpha variant, which first emerged in the U.K., the Beta, first detected in South Africa, and the Gamma, first found in Brazil.