In a disappointing setback for the European Union's vaccination campaign,
German firm CureVac said on Wednesday (June 16) that its COVID-19 vaccine was only 47% effective in a late-stage trial, missing the study's main goal.
The efficacy results are based on 134 COVID-19 cases in the study with about 40,000 volunteers in Europe and Latin America.
At least 13 virus variants accounted for the infections among the study population.
The company added that the interim results suggest the vaccine is effective in younger participants, but did not prove efficacy in those above the age of 60, the age group most at risk for severe COVID.
The stakes for CureVac and prospective buyers of its vaccine in Europe had risen after age limits were imposed on the use of the Johnson & Johnson and AstraZeneca vaccines due to a link to extremely rare but potentially fatal clotting disorders.
The EU secured up to 405 million doses of the vaccine in November, of which 180 million are optional.
The shot was also expected to help in low and middle-income countries that have lagged behind richer nations in the global immunization drive.
Before the emergence of highly effective vaccines, the U.S. Food and Drug Administration had targeted at least 50% efficacy. The World Health Organization had said it was looking for at least 70%.
CureVac's shares sank more than 40% in early trading and were on course for their worst session since their U.S. IPO last August.