Coronavirus (COVID-19): state of the epidemic - 11 February 2022

Resilience: Vaccinations and Antibody Estimates

Vaccinations

Vaccinations started in Scotland on 8 December 2020 and there has been a very high uptake. COVID-19 vaccines protect most people against severe outcomes of a Covid-19 infection, but some people will still get sick because no vaccine is 100% effective. The current evidence suggests that you may test positive for COVID-19 or be reinfected even if you are vaccinated, especially since the emergence of the Omicron variant in the UK. The major benefit of vaccination against Omicron is to protect from severe disease. For more information, see the PHS weekly report.

As at 9 February, around 4.4 million people had received their first dose, which is an estimated 92.1% of the population in Scotland aged 12 and older. Around 4.1 million people had received their second dose, which is an estimated 86.5% of the population aged 12 and older. Additionally, over 3.3 million people in Scotland had received a third vaccine dose or booster, which is an estimated 69.6% of the population aged 12 and older.

As at 9 February, booster vaccine uptake is at least 92% for those aged 60 or over, 89% for those aged 55 to 59, 84% for those aged 50 to 54,73% for those aged 40 to 49, 56% for those aged 30 to 39, 46% for those aged 18 to 29, 11% for those aged 16-17 and 1% for those aged 12 to 15. By Local Authority, the highest uptake of dose 3 or booster of the Covid-19 vaccination as at 9 February was seen in East Dunbartonshire (80%), Argyll and Bute and Shetland (79% each), Orkney and Scottish Borders (78% each), Na h-Eileanan Siar and Dumfries and Galloway (77% each) and South Ayrshire and East Renfrewshire (76% each). The lowest uptake of dose 3 or booster by 9 February was seen across Glasgow (58%), Dundee (62%) and Aberdeen (63%).

In their report published on 2 February 2022, Public Health Scotland provided an analysis on vaccination equality in Scotland^[47]. Vaccination data are from 8 December 2020 to 30 January 2022, and the analysis contains comparisons by ethnicity and socio-economic deprivation by age bands. These analyses highlight differences in uptake between demographic groups and areas, but they do not examine causative factors for the inequalities, which will be numerous and complex

The analysis shows that across all age groups, vaccination uptake for the third or booster dose has been the highest among White ethnic groups. Vaccine uptake was lowest in African ethnic groups, except for those aged 40 to 49 and 50 to 54 years. In these two age groups, vaccination uptake was the lowest among the Caribbean or Black group. There is variation across age within each ethnic group, with higher uptake in older age groups. These trends mirror the uptake of the second dose of the vaccine, as the third or booster dose relies on previous doses being administered.

There is evidence of a drop-off in vaccine uptake between the different doses, meaning that after having either the first or the second dose of the vaccine, a person chose not to have a further dose. When it comes to the difference between the first and the second dose of the vaccine, the proportion of individuals choosing not to have a second dose was highest in the African ethnic group, where 10.5% less of the population aged over twelve receiving the second dose compared to the first. Similarly, drop off between the second dose and the third or booster dose was highest in the African ethnic group, with 31.2% less of the population aged over 16 receiving their third or booster dose compared to their second dose. Across all doses, the difference in uptake between subsequent doses was lowest among the White ethnic group.

Analysis by socio-economic deprivation shows that, across all age groups, uptake of the third or booster dose of vaccination was higher among individuals living the least deprived areas in Scotland. The gap in uptake between the least and most deprived areas ranges from 4.5% in the 80+ age group, to 27.3% in the 40 to 49 age group. These results mirror the uptake of the second dose of the vaccine, as the third or booster dose relies on previous doses being administered.

The drop-off in vaccine uptake between the second and the third dose is the biggest in younger age groups living in more deprived areas. In the most deprived areas, 20.2% less of the population aged over 16 received their third or booster vaccine compared to their second dose. The equivalent figure for those living in the least deprived areas is 9.6%. This pattern is also visible in the vaccine drop-off between the first and the second dose of the vaccine.

More information can be found in the Public Health Scotland Covid-19 weekly statistical report published 2 February 2022. A more detailed breakdown of vaccination uptake by ethnicity, including data for individual NHS Boards, and a more detailed breakdown of vaccination uptake by SIMD decile, including data for individual NHS Boards, can be found in the supplementary tables accompanying the report.

Antibodies Estimates

The ONS Covid-19 Infection Survey estimated that in the week beginning 10 January 2022, 98.3% (95% credible interval: 97.8% to 98.7%) of the adult population (aged 16 or older) living in private residential households in Scotland would have tested positive for antibodies against SARS-CoV-2 at the standard threshold, as a result of having the infection in the past or being vaccinated. This compares to:

• 98.1% in England (95% credible interval: 97.7% to 98.4%),
• 97.7% in Wales (95% credible interval: 97.1% to 98.3%),
• 98.7% in Northern Ireland (95% credible interval: 97.8% to 99.1%).

In Scotland, estimates for the percentage of adults (aged 16+) testing positive for antibodies at the standard antibody threshold ranged from 97.3% in those aged 80 and over (95% credible interval: 95.2% to 98.4%) to 99.1% in those aged 65 to 69 (95% credible interval: 98.7% to 99.4%), in the week beginning 10 January 2022.

The percentage of children who would have tested positive for antibodies against SARS-CoV-2 at the standard antibody threshold is estimated to be 92.9% (95% credible interval: 86.5% to 96.4%) for those aged 12 to 15 years and 72.7% (95% credible interval: 56.9% to 85.0%) for those aged 8 to 11 years in Scotland in the week beginning 10 January 2022^[48].

Vaccine Effectiveness Against Omicron

The Omicron variant (parent Pango lineage B.1.1.529) can be separated into three main groups: BA.1, BA.2 and BA.3. The original Omicron lineage, BA.1, is dominant in the UK, however, there are increasing numbers of BA.2 sequences identified both in the UK and internationally^[49]. Details of risk assessments for both BA.1 and BA.2 carried out by UKHSA can be found on the UK government's website^[50] and in the State of the Epidemic reports (4 Feb & 28 Jan 2022).

The UKHSA reported that vaccine effectiveness against symptomatic disease, hospitalisation or mortality with the Omicron variant is lower compared to the Delta variant, and that it wanes rapidly. Vaccine effectiveness against all outcomes is restored after the booster dose with effectiveness against symptomatic disease ranging initially from around 60 to 75% and dropping to around 25 to 40% after 15 weeks. Vaccine effectiveness against hospitalisation after a Pfizer booster started at around 90% dropping to around 75% after 10 to 14 weeks. Moderna booster restored vaccine effectiveness against hospitalisation to around 90 to 95% up to 9 weeks after vaccination. The high level of protection against mortality was also restored after the booster dose with vaccine effectiveness over 90% 2 or more weeks following vaccination for those aged 50 and older^[51].

Vaccine effectiveness against symptomatic disease with BA.2 compared to BA.1, showed similar results with BA.1 having an effectiveness of around 10% and BA.2 having an effectiveness of around 18% after 25 or more weeks following the second dose. These estimates have large overlapping confidence intervals. The booster dose of vaccine increased effectiveness to around 69% for BA.1 and 74% for BA.2 at 2 to 4 weeks following a booster vaccine. Effectiveness dropped to around 49% for BA.1 and 46% for BA.2 10 weeks after vaccination^[52].

More data on vaccine effectiveness against the Omicron variant can be found in the UKHSA vaccine surveillance reports

There is evidence that there is reduced overall risk of hospitalisation for Omicron compared to Delta^{[53] [54]}, with the most recent estimate of the risk of presentation to emergency care or hospital admission with Omicron was approximately half of that for Delta^[55].