UK Omicron emergency announced

Omicron emergency

No one should be in any doubt, there is a tidal wave of Omicron coming

It is now clear that two doses of vaccine are simply not enough to give the level of protection we all need.

But the good news is that our scientists are confident that with a third dose, a booster dose, we can all bring our level of protection back up

At this point our scientists cannot say that Omicron is less severe

a wave of Omicron through a population that was not boosted would risk a level of hospitalisation that could overwhelm our NHS and lead sadly to very many deaths

Aged 18 and over, in England, third jabs from this week

Three months since second dose

A third booster dose prevents around 75% of people getting any Covid symptoms from Omicron

Live data, hospital patients who have tested positive

Omicron cases have now been found in hospital

Nadhim Zahawi

Warned of the danger of tens of thousands of hospitalisations,

even if omicron were to prove half as severe as delta

SARS-CoV-2 variants of concern and variants under investigation in England

Technical briefing 31

Data cut off, 6 December

260 confirmed cases of Omicron VOC-21NOV-01 (B.1.1.529),

Identified through sequencing or genotyping in England.

Additional possible cases identified through S gene target failure

Higher risk of transmission from secondary attack rates

Risk of household transmission from an Omicron index case compared to a Delta index case 3.2

Risk of a close contact becoming a secondary case, adjusted odds ratio 2.09

Household secondary attack

Omicron, 21.6%

Delta, 10.7%

Three to eight-fold increased risk of reinfection with the Omicron variant.

A 20 to 40-fold reduction in neutralising activity by Pfizer 2-dose vaccinee sera for Omicron

At least 10 fold loss of activity when compared to Delta

Greater reduction in activity was seen for AZ 2- dose sera

An mRNA booster dose resulted in an increase in neutralising activity irrespective of primary vaccination type

Data are urgently required on the durability of neutralising activity

A moderate to high vaccine effectiveness of 70 to 75% is seen in the early period after a booster dose.

With previous variants, vaccine effectiveness against severe disease, has been higher than effectiveness against mild disease

Lateral flow, similar sensitivity to detect Omicron compared to Delta

Modelling the potential consequences of the Omicron SARS-CoV-2 variant in England

Growth rate of the Omicron variant

Level of immune escape

Intrinsic transmissibility

Immune escape of Omicron

5.1-fold to 12.8-fold reduction in neutralisation relative to Delta

Intrinsic transmissibility

Omicron variant is growing in England at an exponential growth rate of r = 0.29 per day

This corresponds to a 2.4-day doubling time

Reproduction number Rt = 4.0

Generation interval of 5.5 days

Surge in SARS-CoV-2 transmission beginning in late December 2021

Infections exceeding peak levels recorded during the January 2021 wave in England

The most optimistic scenario, 1 December to 30 April in England

Omicron has low immune escape and booster jabs are highly effective

20.9 million infections

175,000 hospital admissions

24,700 deaths

Most pessimistic scenario, 1 December and 30 April in England

34.2 million infections

492,000 hospital admissions

74,900 deaths

Conclusions and discussion

Without the implementation of further control measures,

hospital admissions resulting from the Omicron wave of transmission,

could exceed the peak levels recorded in England during the previous winter wave in 2020-2021

In populations with high levels of immunity such as England and South Africa

Omicron variant has the potential to cause significant disruption

In populations with low levels of immunity such Africa

Omicron may or may not out compete delta

Link to free download of my 2 textbooks

Campbell's Pathophysiology Notes, Amazon orders for the UK,

Campbell's Physiology Notes