Coronavirus (COVID-19) state of the epidemic 26 May 2022

Resilience: Vaccine Uptake, Antibody Estimates, and Vaccine Effectiveness

Vaccine Uptake

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. More information is available on the PHS website.

By 23 May, almost 4.4 million people had received their first dose, an estimated 90.3% of the population in Scotland aged 12 and older. Over 4.1 million people had received their second dose, an estimated 85.9% of the population aged 12 and older. Additionally, almost 3.5 million people in Scotland had received a third vaccine dose, which is an estimated 73.0% of the population aged 12 and older^[48].

The JCVI now advise a spring booster dose of the Covid-19 vaccine for: adults aged 75 years and over (or who will turn 75 by 30 June 2022), residents in care homes for older adults, and individuals aged 12 years and over who have a weakened immune system^[49]. By 23 May, 488,710 fourth dose vaccinations had been administered, with 79.8% of all care home residents having received their fourth dose. It is also estimated that 85.2% of those aged 75 or older have received their fourth dose^[50].

Equality of Covid-19 Vaccination Uptake

Public Health Scotland (PHS) publish analysis on the equality of Covid-19 Vaccination uptake. The latest analysis is summarised in the State of the Epidemic report published on 13 May 2022.

For more information on the analysis, methodology, current processes and data sources, please see the PHS Weekly report published on 11 May 2022. Please note that the vaccine uptake rates in this analysis use different denominators than those in the Vaccine Uptake section, so the figures are not directly comparable.

Covid-19 Antibody Estimates

The analysis of antibody prevalence can be used to identify individuals who have had Covid-19 in the past or who have developed antibodies as a result of vaccination. As detailed by the ONS, there is a clear pattern between vaccination and testing positive for Covid-19 antibodies but the detection of antibodies alone is not a precise measure of the immunity protection given by vaccination.

According to the ONS Covid-19 Infection Survey, the estimated percentage of adults (aged 16 years and above) living in private households in Scotland who had antibodies against COVID-19 at the 179 ng/mL threshold remained high, at 99.1% (95% credible interval: 98.7% to 99.3%), in the week beginning 2 May 2022. This suggests that they had the infection in the past or have been vaccinated^[51]. This compares to:

• 99.1% in England (95% credible interval: 98.8% to 99.3%),
• 98.9% in Wales (95% credible interval: 98.4% to 99.2%),
• 98.9% in Northern Ireland (95% credible interval: 97.9% to 99.4%)^[52].

The estimated percentage of adults (aged 16 years and above) living in private households in Scotland who had antibodies against COVID-19 at the 179 ng/mL threshold remained high across all age groups, in the week beginning 2 May 2022.

The antibody series based on the 800 ng/mL level, and antibody estimates for those aged under 16 years in Scotland, were not updated in the latest release from the ONS as they are undergoing additional quality assurance.

Vaccine Effectiveness Against Omicron

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. High 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; however, from 20 or more weeks after the booster dose vaccine, effectiveness against symptomatic disease has almost no effect. Vaccine effectiveness against hospitalisation ranged from 85% to 95% up to six months after the booster dose with little variation between the type of vaccine used for priming or boost. High levels of protection against mortality were also restored after the booster dose, with a vaccine effectiveness of 94% two or more weeks following vaccination, and dropping to around 88% from 10 weeks after the vaccination for those aged 50 and older^[53].

More data on vaccine effectiveness against the Omicron variant can be found in the UKHSA vaccine surveillance reports. There is a reduced overall risk of hospitalisation for Omicron compared to Delta^{[54] [55]}, with the most recent estimate of the risk of presentation to emergency care or hospital admission with Omicron approximately half of that for Delta^[56]. A non-peer reviewed UK study revealed that risk of Covid-19 related death was 67% lower for Omicron when compared with Delta^[57].