Ministers are under pressure to revise official Covid-19 workplace guidance in response to evidence that the new viral variant spreading across the UK is much more infectious than previous forms of the coronavirus.
Officials at Public Health England and the Health and Safety Executive are reviewing the guidelines, as scientists warned that the increased transmissibility of the B.1.1.7 variant could be at the higher end of initial estimates of between 40 and 80 per cent.
“The estimates on the transmission advantage are tightening,” said Professor Neil Ferguson, of Imperial College London. “A 60 to 70 per cent increase is now [scientists’] central estimate.”
Scientists said there was no evidence that B.1.1.7 is transmitted in a significantly different way from previous coronavirus strains or that it spreads more easily among children. The variant is just more contagious in every setting where people meet.
The Trades Union Congress on Tuesday called for an update to the workplace safety rules, pointing out the regulations had not been reviewed since March 2020 to account for “new virus strains or new scientific knowledge about how the virus is spread”.
While most office staff have been urged to work from home there are still millions of people going to work in factories, haulage, construction, hospitals and elsewhere.
“The UK is now battling a strain that is far more easily transmitted,” the TUC said. “Yet the rules have not been fully updated and . . . this is putting workers at risk.”
Scientists’ conclusions about the increased transmissibility of the B.1.1.7 variant have been drawn primarily from epidemiological modelling of the way the strain has rapidly supplanted existing forms of coronavirus since its first known appearance in Kent in late September. At the same time virologists have shown that some of its 17 mutations enable the variant to enter human cells more easily.
Although B.1.1.7 infections seemed to increase even faster among children than adults during the final months of the year, virologists said this was more likely a consequence of social rather than biological factors. The rapid spread of B.1.1.7 occurred while schools were open but most adult routes of transmission were locked down.
“While this variant may not be singling out children in any way, the effect of a general increase in transmissibility across all ages may still affect children uniquely but for societal reasons (schools) rather than biological ones,” said Prof Ferguson.
Peter Openshaw, professor of medicine at Imperial, added: “Paediatricians are looking for an actual increase in Covid disease in children and they are not seeing one.”
One important factor that makes B.1.1.7 more transmissible is that people who are infected with the variant produce much more of the virus in their upper respiratory tract. “The amount of virus secreted per millilitre is increased three- to 10-fold,” said Prof Openshaw. The virus is expelled in tiny droplets when infected people exhale, whether or not they have obvious Covid-19 symptoms.
Another factor is the “increased stickiness of the variant virus”, said Professor Lawrence Young, a virologist at Warwick Medical School. Mutations make the spike protein with which the virus enters human cells “more sticky and this increases the efficiency of infection”.
Despite these mutations, scientists suggested that the government’s messaging on how to minimise the spread of the virus — such as the slogan “hands, face, space” — may not need to change.
“Whatever the mutation, standard measures to restrict transmission — hands, face, space — will prevent infection with this and other variants,” said Prof Young. “These viruses predominantly infect as a consequence of person-to-person contact so restricting contact, wearing face masks and avoiding overcrowded, poorly ventilated inside spaces will prevent transmission.”
But even with such precautions the risk of infection during many activities is now higher, according to Jeffrey Barrett, director of the Covid-19 Genomics Initiative at the Wellcome Sanger Institute. “Our estimate of risk of any activity needs to go up by 50 per cent,” he said. “A 20 minute shopping trip is now probably as risky as a 30 minute trip was before.”
The TUC said it wants workplace safety guidance updated to reduce the number of people permitted in a space at any time, the required wearing of face coverings in all indoors workplaces, a return to 2m social distancing instead of 1.5m and a new safety threshold for ventilation of indoor workplaces with outside air.
The union organisation also called on the government to improve efforts to enforce Covid safety measures, pointing out that during the first lockdown all Health and Safety Executive inspections were stopped.
“With new strains of coronavirus spreading like wildfire, workplace safety rules must catch up,” said Frances O’Grady, TUC general secretary. “Nobody should be put at unnecessary risk because safety policy is behind the science — and unfit to cope with new Covid-19 strains.”