UK HEALTH SECURITY AGENCY (UKHSA)
The findings in a nutshell
Published in late January 2022, this report presents data on COVID-19 cases, hospitalisations and deaths by vaccination status in the UK. The ‘vaccine effectiveness’ section of the report is our focus and summarised below.
Overview of the paper
Several studies of vaccine effectiveness have been conducted in the UK against different COVID-19 variants. Vaccine effectiveness is estimated by comparing rates of disease in vaccinated individuals to rates in unvaccinated individuals. As we are finding in Australia, vaccine effectiveness against symptomatic disease is reduced with the Omicron variant (current dominant variant) compared to with the Delta variant (Delta more common in 2021). Early evidence shows that following the first two doses of the vaccination, there is a rapid ‘waning’ or reduction in effectiveness against the Omicron variant. However, protection against hospitalisation remains high, particularly after a third or booster dose.
Having a booster dose increases antibodies – which is particularly important for Omicron because only some of those antibodies are protective. Emerging evidence suggests protection from symptomatic Omicron infection is restored to 60-75% two to four weeks after a Pfizer or Moderna booster dose. Robust longer-term estimates for booster vaccine effectiveness against infection with the Omicron variant are not yet available. After a Moderna booster (after either primary vaccination course), vaccine effectiveness against hospitalisation for COVID-19 was 90 to 95% up to nine weeks after vaccination.
However, early evidence shows that third-dose protection also wanes, down to 30-40% against Omicron infection after 15 weeks. So, unfortunately breakthrough infections will still be common. Interestingly, vaccine effectiveness is generally slightly higher in younger compared to older age groups.
Post implementation real world vaccine effectiveness studies are needed to understand vaccine effectiveness against different outcomes (such as severe disease, Long COVID syndrome and onwards transmission), effectiveness in different subgroups of the population and against different variants as well as to understand the duration of protection.
Implications for Australian workplaces
Over time, COVID-19 vaccinations will continue to be optimised and improved in the context of effectiveness. For the protection of all Australian workers, it is important for individuals to continue to follow current guidelines regarding vaccinations, particularly maintaining immunity through recommended booster doses. There is an ongoing role for Australian employers in facilitating access to information about vaccination and the vaccinations themselves. Information regarding the currently available Australian COVID vaccines is continuously updated and can be found here.
To find out more about COVID-19 vaccine surveillance report read the full article here.
Date published: 27 January 2022