The UK's National Cyber Security Centre (NCSC) said the hackers "almost certainly" operated as "part of Russian intelligence services".
It did not specify which organisations had been targeted, or whether any information had been stolen.
But it said vaccine research had not been hindered by the hackers.
Russia has denied responsibility.
"We do not have information about who may have hacked into pharmaceutical companies and research centres in Great Britain. We can say one thing - Russia has nothing at all to do with these attempts," said Dmitry Peskov, a spokesman for President Putin, according to the Tass news agency ...
Read the full text bbci.co.uk