Merck is halting the development of its two candidate SARS-CoV-2 vaccines, according to NPR.
In a statement, Merck says Phase 1 clinical studies indicated that its candidate vaccines were well tolerated, but the immune response they generated were not as strong as those elicited by either natural infection or other SARS-CoV-2 vaccines. This, Stat News notes, is a blow to the firm, which had hoped that its approach using viral vectors — one of which it uses in its Ebola vaccine — would lead to long-lasting immunity following a single dose.
NPR adds that Merck will instead focus on further developing two COVID-19 treatments, one of which it hopes will protect the respiratory system from the effects of the disease.
"We're disappointed by this result," Nick Kartsonis, a senior vice president for infectious disease and vaccines at Merck Research Laboratories, tells Stat News. "But it also allows us to continue to focus on our therapeutic candidates and move those forward. And, you know, we are open to continue the work to see if we can address the pandemic in any way we can add value."