London, May 18, 2026, 15:11 (BST)
- GSK shares moved up 0.93% to 1,879.81p. The FTSE 100 gained around 1.0%.
- Japan has cleared GSK’s RSV shot Arexvy for adults 18 to 49 who are at risk. The move expands use of the vaccine.
- GSK said it bought back 1.67 million shares under its buyback programme.
GSK shares traded higher in London on Monday after Japan granted expanded approval for Arexvy, the company’s RSV vaccine. Investors got a new regulatory boost for vaccines as GSK also kept buying back its own shares.
Shares traded at 1,879.81 pence, gaining 0.93%, after starting at 1,855.50p and reaching as high as 1,880.42p, market data show. The FTSE 100 was up 0.99% at 10,296.36.
GSK is counting on wider use for its Arexvy vaccine after choppy demand from buyers. The company last month posted first-quarter sales of £7.6 billion, a gain of 5% at constant exchange rates. But Arexvy sales came in at £0.1 billion, dropping 18%.
GSK said Japan’s Ministry of Health, Labour and Welfare has expanded the use of Arexvy to adults 18 to 49 who face higher risk from RSV. RSV is a respiratory virus that can cause severe illness in some people.
GSK’s head of vaccines and infectious diseases R&D, Sanjay Gurunathan, said the wider approval “can help reduce potentially severe outcomes of RSV.” Arexvy had previous approval in Japan for adults 60 and up, and for at-risk adults 50 to 59, the company said. Investegate
Trial data supported the decision, with at-risk adults ages 18 to 49 showing a non-inferior immune response versus those 60 and older. Non-inferior in this case means the immune response wasn’t significantly worse. GSK reported no new safety concerns, saying the safety profile matched earlier studies.
Arexvy is one of several RSV vaccines on the market. Reuters said in March, after the U.S. label was expanded, that GSK’s shot now faces Moderna’s mRESVIA and Pfizer’s Abrysvo for the 18-49 high-risk adult segment.
GSK said Monday it bought 1,671,851 ordinary shares between May 11 and May 15 via Citigroup, picking up shares at volume-weighted average prices from 1,855.48p to 1,882.24p. The company will keep the repurchased shares as treasury shares instead of cancelling them right away.
GSK’s latest purchases come as part of the final chunk of its £2 billion share buyback. The company is buying back its own shares, which can cut the total number out and boost earnings per share if profits stay level. GSK said this last tranche will be up to around £0.18 billion and should wrap up by June 26.
GSK is still betting on its execution. The company kept its 2026 targets last month, sticking with turnover growth of 3% to 5% and core earnings per share up 7% to 9% at constant exchange rates, which remove currency impacts. Chief Executive Luke Miels said GSK had made “a strong start to 2026.”
But a broader label might not lead to much higher sales right away. Vaccine uptake in Japan will depend on pricing, reimbursement, and policy decisions. Pfizer and Moderna are still strong RSV players. GSK is guiding for 2026 vaccine sales to be flat or down by a low single-digit percentage, so revenue from Japan probably won’t boost the top line much in the near term.
