Coronavirus (COVID-19): state of the epidemic - 4 March 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.

By 2 March, over 4.4 million people had received their first dose, an estimated 92.3% of the population aged 12 and older, and almost 4.2 million people had received their second dose, an estimated 86.9% of the population aged 12 and older. Over 3.4 million people in Scotland had received a third vaccine dose or booster, which is an estimated 71.9% of the population aged 12 and older^[51].

For more analysis on vaccination numbers, see previous publications. For daily updates on vaccination numbers, see the PHS Covid-19 Daily Dashboard. Further analysis on vaccinations will be provided in our next weekly 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 weekly publication. For information on the most recent estimates, see earlier publications or Covid Infection Survey publications.

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BA.1, was dominant in the UK, however, the BA.2 lineage of Omicron is now the dominant variant within Scotland based on unpublished data generated by PHS. Details of risk assessments for both BA.1 and BA.2 carried out by UKHSA can be found on the UK government's website^[52] and in the State of the Epidemic reports published on 4 February and 28 January 2022. The latest BA.2 risk assessment update issued on 25 February indicates that BA.2 has a growth advantage compared to BA.1, however it is likely that the clinical severity of BA.2 is similar to that of BA.1^[53].

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 of 95% 2 or more weeks following vaccination for those aged 50 and older^[54].

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^[55].

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^{[56] [57]}, 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^[58].