Moderna shares slide on concerns over drop in RSV vaccine efficacy

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Moderna

Moderna shares slide on concerns over drop in RSV vaccine efficacy

Feb 9 (Reuters) – Moderna (MRNA.O), opens new tab fell as much as 7% on Friday after Wall Street analysts raised concerns over faster declines in the efficacy of its experimental respiratory syncytial virus (RSV) vaccine when compared with rival shots from GSK (GSK.L), opens new tab and Pfizer (PFE.N).

Data posted on Thursday ahead of an RSV conference next week showed an efficacy of about 63% after 8.6 months in preventing RSV-related respiratory disease, down from 84% at 3.3 months.
 
Moderna’s shares fell to $89 in morning trading, after closing down 5.7% on Thursday.
 
Brokerages TD Cowen and UBS said the data raised questions that the vaccine could show a steeper decline at another long term follow-up of 14 months, giving competitors an edge.
 
The efficacy for GSK’s vaccine, called Arexvy, fell to 77% at 14 months from 83%, while Pfizer’s slipped to 49% in 17 months from 67%, according to TD Cowen.
 
Moderna cautioned against comparing its vaccine, saying the trials for the rival shots used different case definitions for RSV-disease.