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expert reaction to EMA recommendations on extra doses and boosters

The European Medicines Agency (EMA) has announced new recommendations on extra COVID-19 vaccine doses for people with severely weakened immune systems, and booster doses for people aged 18 years and older.


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

“The Committee on Human Medicinal Products (CHMP) of the EMA has been reviewing information on third doses of COVID vaccines for immunecompromised patients and data on booster doses since early September. Today’s press release announces the outcome of today’s extraordinary meeting of the CHMP at which they have approved third doses of the two mRNA vaccines for immunecompromised patients and booster shots in adults 18 and older. The principle difference is that the third dose of vaccine would be given 4-8 weeks after the second vaccine dose in immunocompromised, whereas booster shots would be given 6 months or so after completion of the primary course. Here in the UK, JCVI considered the question of a third dose for immunecompromised patients in August and issued recommendations on 1 September. Booster shots for adults over 50 and high risk adults/adolescents aged 16-49 to be given 6 months (at least) after the completion of a primary course were recommended by JCVI on 14 September. In both recommendations JCVI expressed a preference for mRNA vaccines for this third shot but the AZ vaccine can also be used where appropriate, to facilitate administration. The roll out of these additional doses has already commenced in the UK. In the US, the Advisory Committee on Immunisation Practices and FDA amended the emergency use approvals of the mRNA vaccines to include a third dose of vaccine for immunecompromised patients in August. However, booster vaccine shots of the Pfizer BioNTech vaccine was not approved until September, and ACIP has recommended boosters in individuals aged 65 and older, high risk adults aged 50 to 64 but allows booster vaccines in younger adults over 18 based on individual risks due to background chronic illnesses or occupational exposure. We can expect national immunisation committees in various member states across the EU to make similar determinations based on their own national interests. While these may vary, it is likely that most countries will recommend booster vaccinations for patients at high risk of severe COVID as a basis for use. Use of vaccine boosters is controversial, with WHO continuing to ask that broad use of vaccine boosters be avoided in order to enable provision of additional vaccine doses for countries that have not so far been able to start vaccination campaigns and are unable to vaccinate their populations without increased international help. In addition, some immune compromised individuals may still not respond to vaccination even if given a third shot. In these cases, passive immunisation using one of the monoclonal antibody combination products might be considered as an adjunct to prevent illness post exposure to a COVID case. The coming weeks will see how the member states of the EU will react now that CHMP has extended approvals for the mRNA vaccines. We are likely to see some variation among the member states, but I expect the majority will recommend boosters for higher risk individuals as the winter approaches.”


Dr Benjamin Neuman, Professor of Biology and GHRC Chief Virologist, Texas A&M University, said:

“This decision is welcome, and very much in line with the science.  Recent studies show that antibody levels decline at about the same rates in young and old, and that a third shot boosts antibody levels far higher than two shots.  The benefits of a third shot on increased antibody levels appear to be consistent across age groups, and while risk of death and adverse events from COVID-19 is still skewed toward the older age group, the risks of not boosting still apply to the wider age range.”


Dr Simon Clarke, Associate Professor in Cellular Microbiology at the University of Reading, said:

“This decision by the European Medicines Agency underlines the importance of using three doses of Covid-19 vaccines in adults of all ages.  Claims that most of the immune response is derived from the first dose may well be technically correct, but that does not mean that it offers sufficient protection.

“While the UK booster programme is aimed at over 50s and people who work in frontline health and social care settings, and those with certain conditions, it’s worth noting that Israel also offer boosters to younger adults and has recently made getting one necessary to obtain a ‘green pass’ which allows entry to restaurants, gyms and many other venues.

“While vaccine passports in various forms are being hotly debated in the UK, we risk ignoring the need for booster jabs.  If they become commonplace in the European Union, they may end up being required for travel and will become necessary almost by default.  The UK vaccination programme has been overtaken by several other countries and we may be further left behind if we don’t act quickly enough.”



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



Declared interests

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). These are my personal views and do not reflect those of either institution.”

None others received.

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