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expert reaction to JCVI advice on booster doses

The UK Joint Committee on Vaccination and Immunisation (JCVI) have released their guidance to government on COVID-19 vaccine booster doses.  


Prof Anthony Harnden, Deputy Chair Joint Committee on Vaccination and Immunisation, said:

“A booster vaccination campaign will offer additional protection to the elderly and clinically vulnerable this coming winter, many of whom received their first vaccination at the start of the campaign last December and January.  Public Health England data offers evidence of waning vaccine effectiveness over time.  JCVI’s preference is for a booster with an mRNA vaccine irrespective of the vaccine type used for the primary course.  These vaccines produce a strong immune response as a booster dose.  The booster Covid vaccines can be co-administered with flu vaccines if logistics permit.  Our advice about a booster programme this winter does not imply there will be future booster programmes.”


Prof Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said:

“I’m pleased to see that the government, in response to JCVI advice, have at last confirmed an autumn COVID19 vaccine booster programme.

“There was evidence that an additional boost, either through natural infection or vaccination, would increase levels of immunity, especially to some of the antibody-resistant variants like the Beta variant.  And no doubt data from the CoV-Boost trial has confirmed that.

“I realise that this would not have been an easy decision, especially when a large proportion of the global population have yet to receive a single dose.  But overcoming the issues of vaccine roll-out in less developed regions is not a trivial undertaking and problems extend beyond availability of vaccines.

“Yes, vaccine protection against serious disease is holding up well in the UK, but giving an extra boost to the most vulnerable will help maintain the upper hand, especially as we approach the more challenging autumn and winter months.”


Prof Daniel Altmann, Professor of Immunology, Department of Immunology and Inflammation, Imperial College London, said:

“On balance this is good news.  Boosters will likely enhance antibody and T cell immunity in most, and more immunity is better than less, especially with a punitive foe such as delta.  It was a given that we need a programme for those groups identified as having typically made poor responses to the first two doses.  To a large extent, real life data such as that from Israel makes an unassailable case for boosters more widely: a population with  longstanding 2-dose Pfizer vaccination was suffering badly from delta breakthrough cases, especially in over 60s.  The booster has brought that curve right back down.”


Dr Doug Brown, Chief Executive of the British Society for Immunology said:

“While we are entering a new era of the COVID-19 pandemic, the risk posed by serious disease is certainly not yet over and we need careful planning to ensure the safety of the population while minimising the impact of the pandemic throughout the autumn and winter.

“In the absence of long term evidence of immunity, offering a booster COVID-19 vaccination to those most vulnerable to COVID-19 will likely provide additional protection from the virus for many across the UK.  Booster doses of the Pfizer-BioNTech and Moderna vaccines have been tested in clinical studies and have been found to be safe and effective at boosting the immune response.

“To inform all future decisions around vaccine use, it is crucial that we continue to collect and scrutinise data on the durability of protection provided by these vaccines and on other important unanswered questions.  We still do not yet fully understand the relationship between the immune response generated by COVID-19 vaccines and effective protection against the virus, and how long that immunity lasts.  Through supporting ongoing and future research studies we will be best informed as to how we can most effectively live with this virus.

“It is also key that we ensure that as many people as possible are vaccinated against COVID-19 as this is the best way to prevent severe disease and the spread of the virus.  Although there has been a high uptake of the vaccines in the UK so far, a significant number of people still need to come forward for a first or second dose.  We must not take our foot off the gas and continue to make every effort to reach these people and encourage them to come forward for a COVID-19 vaccination.

“The UK government has made this decision regarding boosters though this pandemic is not restricted to UK shores.  We must redouble efforts to make COVID-19 vaccines available around the world as this is the most effective way to both protect people as well as prevent the emergence of new variants.”


Prof Penny Ward, Independent Pharmaceutical Physician, Visiting Professor in Pharmaceutical Medicine at King’s College London, said:

“The advice from JCVI today concerning a booster program for covid vaccines among the higher risk adult population is a natural follow on from the observed waning in vaccine effectiveness noted as time from the completion of primary two shot vaccination course extends, particularly in older people.  Despite this being an apparently low fall off (e.g. from 90 to 80% protection), on a population basis that small difference is likely to translate into significant numbers of people needing hospital care for COVID, with all that implies for additional strains within the NHS if nothing further is done.  By intervening now to boost protection against disease – as observed in the emerging data from the booster program in Israel – this risk should be reduced.  Regrettably the data which underlies the JCVI’s preference for mRNA vaccine booster doses has not yet been made public so the precise reason for this recommendation cannot be assessed.  In general, heterologous vaccination is often more effective at boosting immunological response than homologous vaccination so one might have anticipated that, in people over 40 that have received a primary course with an mRNA vaccine might have been recommended to have a booster shot with the AZ vaccine.  The absence of this recommendation suggests that perhaps the immunological response to a booster shot with this vaccine does not achieve the same level as a third shot with an mRNA vaccine, but we will have to wait for the publication of the results of the Cov-Boost trial to understand this recommendation completely.  Nonetheless, where individuals have a specific contraindication to the mRNA vaccines, they can be given a booster shot of the AZ vaccine instead, which implies that there is a boosting effect from the AZ vaccine that is better than not having a booster shot at all.  It would of course have been helpful for the data underlying this decision to have been made public at the same time as the recommendation.  These studies were publicly funded and the analysis has been completed in time to affect decision making and should be made available to prescribers, who will need access to these data to be able to answer questions from patients.

“The issue of global vaccine equity is separate to this decision.  By supporting the development of the AZ vaccine, which is, now, widely produced and available at low cost internationally, and by the financial support given to GAVI and COVAX, the UK government has already contributed significantly to global health and to protecting overseas populations against COVID.  However their first duty, as the government of a democratic nation, is to protect the health and wellbeing of the UK population they serve.”


All our previous output on this subject can be seen at this weblink:


Declared interests

Prof Jonathan Ball: “In receipt of UKRI vaccine development funding.”

Dr Doug Brown: “I am a Trustee of the Association of Medical Research Charities.”

Dr Penny Ward: “No COIs. I am semi-retired, but I am owner/Director of PWG Consulting (Biopharma) Ltd a consulting firm advising companies on drug and device development. Between December 2016 and July 2019 I served as Chief Medical Officer of Virion Biotherapeutics Ltd, a company developing antiviral treatments for respiratory viral diseases. Previous employee of Roche, makers of tocilizumab (anti IL6 antibody) and CMO of Novimmune, makers of empalumab (anti IFN gamma antibody).”

None others received.

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