Limiting autumn Covid boosters to the over-80s, and high-risk over-45s, would have been the most cost-effective option, according to a Government impact assessment.
But the Joint Committee on Vaccination and Immunisation (JCVI) decided to take a ‘precautionary’ approach in selecting who should be eligible for a booster jab because of uncertainties in the modelling, including around NHS winter pressures and the risk of a more significant wave of Covid than planned for.
This is the first time that the JCVI has factored cost-effectiveness into its advice on eligibility for Covid-19 vaccines.
Several scenarios were considered for the impact assessment including the JCVI recommended policy of vaccinating the over-65s and those aged 6 months to 64 years and in a clinical risk group. Front line workers and the immunosuppressed were not considered in the analysis.
It found that while the JCVI recommendations were cost-effective overall, there were some cohorts that were not including healthy 65-79-year-olds and those under the age of 45 in a clinical risk group not counting those who are immunosuppressed.
But in the justification for the decision, the committee said: ‘Given the high proportion of older adults with comorbidities and the higher uptake seen in universal age-based programmes, JCVI considers that for autumn 2023, it is appropriate to offer vaccination to all adults aged 65 years and over.’
The committee decided to take this approach during the current pandemic recovery phase due to uncertainties in the number needed to vaccinate and cost-effectiveness estimates but also ‘because of the expected additional benefits of reducing winter pressures on the NHS’.
In addition, further stratification of at-risk groups to those over a certain age would increase the programme’s complexity and could negatively impact uptake, the JCVI added.
The impact assessment also looked at the option of sticking with vaccinating the over 50s as had happened in last year’s booster programme but it was found to have a negative net monetary benefit. The analysis did note that this option also has the greatest unquantified benefits such as protecting NHS capacity and preventing long-Covid.
It estimated that the JCVI approach would prevent 4,090 deaths and 14,720 hospitalisations compared with 4,020 deaths and 13,990 hospitalisations if the more restricted cohorts had been chosen.
A pre-print of a study from the UK Health Security Agency also published this week on the impact of two Covid vaccines used in the spring booster campaign found around a 50% effectiveness against hospitalisation above any remaining protection from previous vaccination.
Researchers compared the Pfizer/BioNTech bivalent vaccine and the Sanofi/GSK monovalent jab which was the first adjuvanted vaccine to be used in the Covid-19 vaccine programme.
They found that both were about 50% effective against hospitalisation initially amongst adults aged 75 years and older waning to about 30% five to nine weeks after vaccination.
Dr Mary Ramsay, director of immunisation at UKHSA said: ‘This study, which estimated the vaccine effectiveness of two of the spring booster vaccines against hospitalisation for those aged 75 and over in England, shows the vaccines significantly boost people’s protection helping keep those most vulnerable out of hospital.
‘Vaccine effectiveness was estimated in addition to the waning protection provided from the previous autumn booster. Both boosters gave around 30-50% additional protection against severe illness and hospitalisation with some waning after ten or more weeks.’