Correspondence

Letter to the profession from the UK Chief Medical Officers regarding the UK COVID-19 vaccination programmes

Published 31 December 2020

Dear colleagues,

Thank you for your remarkable commitment to the health of our nation in the most difficult of circumstances; the COVID-19 pandemic is undoubtedly the biggest health crisis in a generation, and certainly in our professional lifetimes. We are at a critical point in the pandemic as the emergence of a novel variant of SARS-CoV-2 with a markedly higher growth rate is rapidly shifting the epidemiological curve in the wrong direction across much of the UK in the middle of winter.

Authorisation of first the Pfizer and now the AZ vaccine (AZD1222) for use is incredibly welcome. Both are highly effective vaccines from clinical trial data and are anticipated to have sizeable effects on preventing severe disease and hospitalisation. Getting vaccines deployed as rapidly as possible into as many older, clinically vulnerable patients, and also frontline health and social care workers is essential. The Joint Committee on Vaccination and Immunisation (JCVI) has put forward a prioritisation scheme, attached, of which you will all be aware.

We wanted to lay out to you the scientific and public health rationale for the dosing schedule for the AZ vaccine and the change to the dosing schedule for the second dose of the Pfizer vaccine. As with all decisions during this pandemic it is about balance of risks and benefits.

1. We have to ensure that we maximise the number of eligible people who receive the vaccine. Currently the main barrier to this is vaccine availability, a global issue, and this will remain the case for several months and, importantly, through the critical winter period. The availability of the AZ vaccine reduces, but does not remove, this major problem. Vaccine shortage is a reality that cannot be wished away.

2. We are confident that based on publicly available data as well as data available to the JCVI, the statutory independent body, that the first dose of either Pfizer or AZ vaccine provides substantial protection within 2-3 weeks of vaccination for clinical disease, and in particular severe COVID disease. The JCVI has issued a new evidence statement today.

3. The second vaccine dose is likely to be very important for duration of protection, and at an appropriate dose interval may further increase vaccine efficacy. In the short term, the additional increase of vaccine efficacy from the second dose is likely to be modest; the great majority of the initial protection from clinical disease is after the first dose of vaccine.

4. In terms of protecting priority groups, a model where we can vaccinate twice the number of people in the next 2 to 3 months is obviously much more preferable in public health terms than one where we vaccinate half the number but with only slightly greater protection.
5. This is why the JCVI has recommended that first doses of vaccine are prioritised for as many people as possible on the Phase 1 JCVI priority list, in advance of second doses which will subsequently provide more assured longer-term protection. It is a classic public health approach centred on doing as much good for as many people in the shortest possible timeframe, within the available vaccine supplies, against a background of immediate disease activity and still high population sero-susceptibility (despite the disease burden seen).
6. The JCVI is confident 12 weeks is a reasonable dosing interval to achieve good longer-term protection.
7. The position is strongly supported by the UK Chief Medical Officers on public health grounds of maximising benefit.

We recognise that the request to re-schedule second appointments is operationally very difficult, especially at short notice, and will distress patients who were looking forward to being fully immunised. However, we are all conscious that for every 1000 people boosted with a second dose of COVID-19 vaccine in January (who will as a result gain marginally on protection from severe disease), 1000 new people can't have substantial initial protection which is in most cases likely to raise them from 0% protected to at least 70% protected. Whilst the NHS, through all of your work, has so far vaccinated over 1 million UK patients with a first dose,approximately 30 million UK patients and health and social care workers eligible for vaccination in Phase 1 remain totally unprotected and many are distressed or anxious about the wait for their turn. These unvaccinated people are far more likely to end up severely ill, hospitalised on in some cases dying without vaccine. Halving the number vaccinated over the next 2-3 months because of giving two vaccines in quick succession rather than with a delay of 12 weeks does not provide optimal public health impact.

We have to follow public health principles and act at speed if we are to beat this pandemic which is running rampant in our communities and we believe the public will understand and thank us for this decisive action. We hope this has your support.

We attach a statement from the JCVI laying out their thinking in more detail.

Once again, many thanks.

Yours sincerely,

Dr Frank Atherton, Chief Medical Officer, Wales

Dr Michael McBride, Chief Medical Officer, Northern Ireland

Dr Gregor Smith, Chief Medical Officer, Scotland

Professor Chris Whitty, Chief Medical Officer, England

Professor Jonathan Van-Tam, Deputy Chief Medical Officer, England