The world is facing a surge in hospitalisations and deaths from the omicron variant of the coronavirus that could be as bad as in previous waves, even if omicron is only a third as severe as the delta variant – and so far, data from England does not suggest it is any less severe, according to a team at Imperial College London.
What’s more, countries are fast running out of time to do anything to limit the impact. The UK is in a better position than most countries because it has already rolled out vaccine boosters to older people but has less time left to act, says team member Neil Ferguson.
“Time is of the essence,” says Ferguson. “I think if we are going to have to make additional decisions, they probably will need to be made within the next week or two to have a substantial impact.”
“The key message coming from this is: countries need to prepare,” says team member Azra Ghani. That means rolling out boosters as fast as possible and implementing additional measures such as mask wearing and social distancing, she says.
Independent SAGE, a self-appointed group of experts who provide covid-19 advice aimed at the UK government, says a “circuit-breaker” should be implemented throughout the UK immediately to prevent omicron from spiralling out of control. It is calling for indoor hospitality to shut, no indoor gatherings between households, no outdoor gatherings of more than 6 people and a return to 10-day isolation for people who have come into close contact with cases. But the UK government has said that no further measures would be introduced.
The Imperial team used data from the UK and from lab studies to estimate how much less protection people have against omicron than delta, in terms of preventing infection, severe disease requiring hospitalisation and death.
There are many uncertainties but the team concludes that people who had two vaccine doses or past infections have lost almost all protection against infection and a substantial amount of protection against severe disease and death.
Providing booster shots will therefore be vital, but that alone may not be enough, says Ghani. The team estimates that 60 days after having a Pfizer booster, protection against severe disease could be as low as 80 per cent for omicron, compared with 95 per cent with delta.
“With omicron and the reduced vaccine efficacy we are seeing, it’s very likely that most places will need booster doses,” she says. “But even with these in place we could still see peaks [in deaths] that match previous peaks [of the pandemic].”
Despite this troubling data, we are not back to square one on vaccine coverage, says Danny Altmann at Imperial College London and Independent SAGE.
“[With just] two vaccine doses you’re really extremely susceptible,” he says. However, “I think for most people most of the time, a boost gets you into the protective zone, so we’re in danger but not back to square one.”
Christina Pagel at University College London and Independent SAGE agrees. “Two doses of vaccine, whether AstraZeneca or Pfizer, do little to prevent omicron infection. A booster does help, it’s a lot better than two doses, but it’s still not as good as a booster would have been for delta. However, vaccines should still help significantly against severe disease.”
However, vaccine coverage is still quite low, says Pagel. London, which is the UK’s omicron hotspot, has the highest proportion of unvaccinated people (31 per cent) and the lowest proportion of boosted people (27 per cent) in England. And no place in the UK has over 50 per cent of people boosted, she says.
In separate research, an international team tested the effectiveness of six vaccines against omicron. It found that all of them – Pfizer, Moderna, AstraZeneca, Sinopharm, Johnson & Johnson and Sputnik – produced fewer antibodies that neutralise omicron than the original coronavirus, and the latter three produced hardly any. The research has yet to be peer-reviewed.
The team says that UK data so far do not suggest the risk of becoming severely ill is any lower with omicron than with delta. However, this means the risk to people with no immunity, Ferguson made clear. Because most people do now have immunity, the proportion requiring hospitalisation should be lower than in previous waves, but this is factored into the modelling.
“People should not be complacent,” he says. “If you have enough cases per day, the resulting number of hospitalisations, we think, can still pose potentially major challenges for any health system.”
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