9:31 PM 31st December 2021
COVID-19 Variants Identified In The UK - 31 December 2021
UKHSA publishes updated Omicron hospitalisation and vaccine efficacy analysis
The UK Health Security Agency (UKHSA) has published a new variant technical briefing containing updated analysis on Omicron hospitalisation risk and vaccine efficacy against symptomatic disease and hospitalisation.
Protection against hospitalisation from vaccines is good against the Omicron variant. One dose of any vaccine was associated with a 35% reduced risk of hospitalisation among symptomatic cases with the Omicron variant, 2 doses with a 67% reduction up to 24 weeks after the second dose and a 51% reduced risk 25 or more weeks after the second dose. A third dose was associated with a 68% (95% confidence interval 52 to 82%) reduced risk of hospitalisation when compared to similar unvaccinated individuals. When the reduced risk of hospitalisation was combined with vaccine effectiveness against symptomatic disease, the vaccine effectiveness against hospitalisation was estimated as 52% after one dose, 72% 2 to 24 weeks after dose 2, 52% 25+ weeks after dose 2 and 88% 2 weeks after a booster dose.
"This is more promising data which reinforces just how important vaccines are.
As set out last week, the effectiveness of all vaccines against symptomatic infection continues to be lower in all periods against Omicron compared to Delta. The latest data confirmed that among those who had received 2 doses of AstraZeneca, there was no effect against Omicron from 20 weeks after the second dose. Among those who had received 2 doses of Pfizer or Moderna, effectiveness dropped from around 65 to 70% down to around 10% by 20 weeks after the second dose. Two to 4 weeks after a booster dose, vaccine effectiveness ranged from around 65 to 75%, dropping to 55 to 70% at 5 to 9 weeks and 40 to 50% from 10+ weeks after the booster.
Working alongside Cambridge University MRC Biostatistics unit, UKHSA analysed 528,176 Omicron cases and 573,012 Delta cases between 22 November and 26 December to assess the risk of hospitalisation in England after testing positive for Omicron. This analysis found that the risk of presentation to emergency care or hospital admission with Omicron (testing for symptomatic or asymptomatic infection) was approximately half of that for Delta, while the risk of hospital admission alone with Omicron was approximately one-third of that for Delta. In this analysis, the risk of hospitalisation is lower for Omicron cases with symptomatic or asymptomatic infection after 2 and 3 doses of vaccine, with an 81% (95% confidence interval 77 to 85%) reduction in the risk of hospitalisation after 3 doses compared to unvaccinated Omicron cases.
This analysis is not an assessment of hospital severity, which will take further time to assess.
Health and Social Care Secretary Sajid Javid said:
"This is more promising data which reinforces just how important vaccines are. They save lives and prevent serious illness. This analysis shows you are up to 8 times more likely to end up in hospital as a result of COVID-19 if you are unvaccinated.
"It is never too late to come forward for your first dose and it’s vital that everyone comes forward to get boosted now as we head into the new year."
Susan Hopkins, Chief Medical Adviser at UKHSA, said:
"The latest set of analysis is in keeping with the encouraging signs we have already seen.
"However, it remains too early to draw any definitive conclusions on hospital severity, and the increased transmissibility of Omicron and the rising cases in the over 60s population in England means it remains highly likely that there will be significant pressure on the NHS in coming weeks.
"The data once again shows that coming forward for your jab, particularly your third dose, is the best way of protecting yourself and others against infection and severe disease."