June 30 (Reuters) – CureVac (5CV.DE) said its COVID-19 vaccine was 48% effective in the final analysis of its pivotal mass trial, only marginally better than the 47% reported after an initial read-out two weeks ago.

The German biotech firm said that efficacy, measured by preventing symptomatic disease, was slightly better at 53% when excluding trial participants older than 60 years, an age group that is by far the most severely affected.

CureVac said on June 16 its COVID-19 vaccine, known as CVnCoV, proved only 47% effective in an initial trial read-out and that new variants had proved a headwind, denting investor confidence in its ability to take on rival shots.

That wiped billions of euros from its market value.

Wednesday’s news sent U.S.-listed shares of the company 10.2% lower to $66 after the bell.

Late-stage trials of BioNTech/Pfizer (22UAy.DE), (PFE.N) and Moderna (MRNA.O) vaccines, which like CureVac’s are based on mRNA technology, had efficacy rates of well above 90% across all age groups but took place when the original version of the coronavirus was dominant.

Data on their products have, however, so far suggested only somewhat weaker protection against new variants.

The CureVac study, which involved about 40,000 adult volunteers in Europe and Latin America, showed that efficacy was 77% in the age group below 60 years of age when considering only moderate to severe symptoms and excluding mild cases.

CureVac said it had sent the data to the European Medicines Agency (EMA) as part of an ongoing dialogue with the EU drugs regulator.

CureVac previously said that the regulatory hurdle was 50% efficacy in principle but that various other considerations would come into play.

“In this final analysis, CVnCoV demonstrates a strong public health value in fully protecting study participants in the age group of 18 to 60 against hospitalization and death and 77% against moderate and severe disease – an efficacy profile, which we believe will be an important contribution to help manage the COVID-19 pandemic and the dynamic variant spread,” said Chief Executive Officer Franz-Werner Haas.

CureVac had registered 228 infections overall for the final analysis, after 134 cases for the interim analysis.

Public health representatives across the globe are pushing for a fast deployment of available vaccines to counter highly contagious mutations of COVID-19 such as the Delta variant that first emerged in India.

The EMA has said it would not impose a 50% efficacy threshold for vaccines and that full trial data was necessary for it to make a sound assessment on the benefits and risks of a shot. read more

Under CureVac’s only major supply deal for the product tested in the trial, the European Union secured up to 405 million doses of the vaccine in November, of which 180 million are optional.

In a bet on CureVac’s technology, Britain placed a conditional 50 million dose order in February on yet-to-be-developed vaccines that build on the product tested in the trial. read more

CureVac had lined up a network of manufacturing partners including Celonic Group of Switzerland, Novartis (NOVN.S), Bayer (BAYGn.DE), Fareva, Wacker (WCHG.DE) and Rentschler Biopharma SE.

($1 = 0.8377 euros)

Reporting by Ludwig Burger, Editing by Rosalba O’Brien

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