After GSK PLC (LSE:GSK, NYSE:GSK) shares fell sharply on the back of US authorities restricting doses of respiratory syncytial virus (RSV) vaccine, analysts argued that the reaction seemed over the top.
Shares in Pfizer and Moderna, which also make RSV vaccines, fell 2% and 11% in New York overnight.
The US Centers for Disease Control and Prevention’s (CDC) advisory committee on immunization practices (ACIP) unanimously voted to restrict RSV vaccine recommendation to defined at-risk 60-74s, whilst expanding use for all 75 and older.
The committee saw a potentially elevated risk of neuroinflammatory condition Guillain-Barré syndrome (GBS).
These decisions may cut the 2024-25 addressable US market from around 80 million people aged 60-plus as well as circa 13 million at-risk aged 50-59, to perhaps circa 55 million, said analysts at Jefferies, with around 10 million dosed last season.
This was despite evidence suggesting Arexvy does not statistically increase risk, the Jefferies analysts noted, adding that as additional real-world safety data accumulate “the recommendation may be expanded”.
Sean Conroy at Shore Capital said his near-term forecasts are “unlikely to be at risk given most of the initial uptake is expected to be in the higher risk and more frail populations who are likely the most motivated to take preventative vaccines.”
Second, he said the decision “doesn’t preclude future ACIP recommendations being more permissive once GSK can further demonstrate the safety, efficacy, and cost-effectiveness” of the vaccines.
Moderna RSV data was presented to the ACIP, which Jefferies said was “as expected”, though the data was less competitive at 50% protection compared to GSK’s Arexvy’s 67%-75%.
The ACIP meeting is ongoing and Moderna’s Phase III data “should support a positive recommendation for use for people over 60+ yo later today”, the Jefferies team added.
