Shares in GSK slid on Wednesday despite the UK drugmaker reporting better than expected financial results, as investors were unnerved by weaker sales of its respiratory syncytial virus (RSV) and shingles vaccines and recently launched medications.

Britain’s second-biggest pharmaceutical company reported a 19% decline in pre-tax profit to £1.9bn in the July to September quarter and £318m of restructuring charges, with more to come. Core operating profit and core earnings per share rose 5% and 1% respectively, however, beating analysts’ expectations.

Shares dived as much as 7% at one point on Wednesday, and despite later paring back such losses to a 3.8% drop, it was the second-biggest faller on the FTSE 100 index of blue-chip businesses.

Luke Miels, who took over from Emma Walmsley as GSK’s chief executive in January, has announced a number of acquisitions , including a £7.9bn US cancer specialist and a major cost-saving programme in July to speed up drug development.

GSK said turnover in the third…