Dr Carrie St John Wright outlines what we know about administering the third Covid vaccine dose to vulnerable groups
The Joint Committee on Vaccinations and Immunology (JCVI) has set out plans for the Covid booster campaign, set to take place from September. Most notably, it has said a ‘synergistic approach to the delivery of Covid-19 and influenza vaccination could support delivery and maximise uptake of both vaccines’.1
The JCVI proposes a two-stage process:
• Stage 1, from September 2021:
– adults aged 16 years and over who are immunosuppressed
– those living in residential care homes for older adults
– all adults aged 70 years or over
– adults aged 16 years and over who are considered clinically extremely vulnerable
– frontline health and social care workers.
• Stage 2, following as soon as possible after stage 1, likely around 17 December:
– all adults aged 50 years and over
– adults aged 16 to 49 years who are in an influenza or Covid-19 at-risk group (those who would usually be offered a flu jab and those who would be viewed as clinically vulnerable for Covid)3,4
– adult household contacts of immunosuppressed individuals.
As younger adults will only recently have received their first and second doses, the booster for this group will be considered in due course.
There is good evidence that a full course of any Covid-19 vaccine used in the UK will provide good protection against severe disease for at least six months for the majority, and there is some evidence that longer-lasting protection may be afforded.1 The JCVI is looking at clinical trials and real-world effectiveness data on the durability of protection beyond six months and at clinical trial data on immune responses following a third vaccination, so advice may alter with time.
The UK Government has funded the CovBoost trial, which will look at seven vaccines being considered for the booster programme, around 10 to 12 weeks after the second dose. It is likely to report in September. Vaccines being trialled include Oxford AstraZeneca, Pfizer BioNTech, Moderna, Novavax, Valneva, Janssen and Curevac, alongside a control group.
The JCVI said it will review the use of the vaccines that have not yet received UK regulatory approval.
Co-administration with the flu vaccine
Vaccines designed to counter specific variants will not be available in time for booster revaccination this autumn, and will be considered by JCVI ‘in due course’.1 Trial data on mixing vaccines are also to be taken into consideration when available. The data on the immune benefits of mixing vaccines and of boosters are still being looked at as part of the ComCov and CovBoost studies.
Because of last year’s lockdowns and social distancing, there is a concern that there may be a lower level of population immunity against influenza.
The JCVI says this winter flu season ‘could be up to 50% larger than typically seen’ and may begin earlier than usual. To mitigate this, it has advised extension of the influenza vaccination programme to adults aged 50 years and over for winter 2021-22.1
The JCVI says adverse effects from co-administering the flu and Covid vaccines are unlikely, quoting as-yet unpublished evidence from the National Immunisation Schedule Evaluation Consortium. Co-administering both vaccines at the same appointment will allow more efficient use of resources and a better service for patients, as well as helping to improve uptake of both jabs, the committee says.
This will only be possible where supply, regulation and alignment of cohorts allows. Enhanced service information from NHS England came out in July and does not allow for Covid vaccinations to be given in GP practices. It has been suggested that co-administration with flu vaccines will be achieved by practices pooling their flu vaccines to be given at PCN level with Covid boosters. However, as previously stated, trial data are awaited so information on this will be released as it becomes available.
Those who are severely immunocompromised – for instance those with solid organ transplants – have been prioritised for booster jabs as they may not respond as well to Covid vaccines and are at much higher risk of severe disease. The JCVI advises that severely immunosuppressed adults should be offered booster vaccines at the start of the booster programme.
Unless otherwise eligible, adult household contacts of immunosuppressed individuals should be offered booster revaccination alongside those in stage two.
NHS England has said local systems should ‘continue to deliver routine vaccination programmes for children and for adults, maintain an “evergreen” offer to all adults who have not yet had a first Covid vaccination, and complete any second doses not yet delivered’.
It also wants ‘every contact to count’, suggesting that GPs could do other screening at these appointments, including BP or AF checks. It is unclear what evidence there is for this or whether the NICE screening committee has indicated it would be helpful.
Delivery will be achieved by spreading capacity across community pharmacy, vaccination centres and general practice to ensure there is enough time for ‘business as usual’ in general practice. Maximum use will be made of community pharmacy, pop-up centres, and mobile units, recognising that ease of access improves vaccine uptake.7
What we need to know
Other data that will soon become available and will require further consideration by the JCVI include:
- The safety and effectiveness of Covid-19 vaccines used in the UK and internationally.
- Clinical trial and real-world effectiveness data on the durability of protection beyond six months.
- Clinical trial data on immune responses following a third vaccination (booster revaccination).
- Clinical trial data on reactogenicity and immunogenicity following booster revaccination with the same or alternative Covid-19 vaccines.
- Clinical trial data on other Covid-19 vaccines in development.
- The emergence of any new variants of concern in the UK or internationally.
- Data on the duration of immunity following a primary course.
- A better understanding of the immune correlates of protection.
- Data on the effects of ongoing SARS-CoV2 circulation in the population and its potential to confer long-term immunity which has potential public health benefits.2
Dr Carrie St John Wright is a GP and appraiser in Bristol.
- Department of Health and Social Care, 2021. JCVI interim advice on a potential coronavirus (Covid-19) booster vaccine programme for winter 2021 to 2022.
- Department of Health and Social Care, 2021. Most vulnerable could be offered booster Covid-19 vaccines from September.
- Public Health England, October, 2020. The Green Book, chp 19: influenza.
- Public Health England, July, 2021. The Green Book, chp 14a: Covid-19.
- Department of Health and Social Care. New government-funded clinical trial looking at different Covid-19 ‘booster’ vaccines launches in the UK. 2021.
- Mahon B. AstraZeneca jab recipients to get different booster shot. The Times, 30 July, 2021.
- NHS England, 2021. COVID-19 Vaccination Autumn / Winter (Phase 3) planning.