Coronavirus (COVID-19): state of the epidemic - 1 April 2022

Resilience: Vaccinations, Antibody Estimates, and Variants

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.

From 24 March 2022, PHS began reporting the number of people who have received a fourth dose of Covid-19 vaccination and they will include further updates as the Spring/Summer vaccination programme rolls out. In addition, the methodology of counting the vaccine uptake statistics have been reviewed to be in line with other UK nations. This means that from 24 March 2022, the deceased and those who no longer live in Scotland will no longer be included in vaccine uptake statistics. As a result of this change, figures in the current report might appear lower than figures reported the previous week. More details on the methodology changes are available on PHS website.

By 30 March, almost 4.4 million people had received their first dose, an estimated 90.4% of the population aged 12 and older, and almost 4.1 million people had received their second dose, an estimated 85.5% of the population aged 12 and older. Almost 3.5 million people in Scotland had received a third vaccine dose, an estimated 72.1% of the population aged 12 and older^[60].

The JCVI now advise a spring booster dose of the COVID-19 vaccine for: adults aged 75 years and over, residents in care homes for older adults, and individuals aged 12 years and over who have a weakened immune system^[61]. By 30 March, 79,884 fourth dose vaccinations had been administered, with 34.3% of all care home residents having received their fourth dose^[62].

For more analysis on vaccination numbers, see previous publications. Further analysis on vaccinations will be provided in our next release, to align with ONS publications of antibody estimates based on the Covid Infection Survey.

Antibodies Estimates

Estimates on the proportion of people in the private residential population in Scotland that would test positive for antibodies against SARS-CoV-2 are published by the ONS Covid-19 Infection Survey. The next scheduled release of antibody data from the Covid-19 Infection Survey will be incorporated into our next publication. For information on the most recent estimates, see earlier Covid Infection Survey publications.

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. 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 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. The high level of protection against mortality was also restored after the booster dose with vaccine effectiveness of 95% two or more weeks following vaccination for those aged 50 and older^[63].

Vaccine effectiveness against symptomatic disease with Omicron BA.2 compared to Omicron BA.1, showed similar results, with BA.1 having an effectiveness of below 20% and BA.2 having an effectiveness of above 20% after 25 or more weeks following the second dose. The booster dose of vaccine increased effectiveness to around 70% for BA.1 and BA.2 at two to four weeks following a booster vaccine. Effectiveness dropped to around 50% for BA.1 and BA.2 15 weeks after vaccination. Vaccine effectiveness against hospitalisation ranged from 83% for BA.1 to 87% for BA.2 at 14 to 34 days after the booster dose, and dropped to 73% for BA.1 and 70% for BA.2 after 70 days. These estimates have large overlapping confidence intervals^[64].

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^{[65] [66]}, with the most recent estimate of the risk of presentation to emergency care or hospital admission with Omicron approximately half of that for Delta^[67]. A recent, non-peer reviewed UK study revealed that risk of COVID-19 related death was 67% lower for Omicron when compared with Delta^[68].