Sales of £9.1bn in the first three months of the year were up 19% on a year ago, boosted mainly by strong demand for its Shringrix shingles treatment and increased demand for many products.
Pharmaceutical sales were up 6% to £4.4bn, vaccines were up 19% to £1.8bn and consumer healthcare revenues rocketed 44% to £2.9bn.
Sales of HIV and respiratory products were lifted towards the end of the quarter by additional demand and customer stock building in Europe and the US related to the Covid-19 pandemic, but this was partly offset by lower sales in China, which GSK said reflected different stages in the progress of the pandemic.
Operating profit rose 41% to £2bn, with underlying earnings per share up 26% to 37.7p.
Analysts on average expected sales of £8.75bn and EPS of 31.5p per share.
Like big pharma rival AstraZeneca earlier in the day, Glaxo kept its 2020 guidance unchanged, expecting a reduction of 1-4% in earnings.
Chief executive Emma Walmsley said: “Responding to the Covid-19 pandemic is at the heart of our purpose as a company and GSK’s portfolio is both highly relevant and needed.
She added: “We have also taken action to deploy our science and technologies. Our primary aim is to develop multiple adjuvanted COVID-19 vaccines, and we are working with companies and institutions across the world to do so.”
The shares were down 0.3% to 1,682p by mid-afternoon.