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expert reaction to announcement from JCVI recommending that an additional booster dose is offered to all adults over-75 and the most vulnerable over-12s in the UK this spring

The Joint Committee on Vaccination and Immunisation (JCVI) has advised additional boosters be offered to people aged 75 and over, residents in care homes for older adults, and those aged 12 and over who are immunosuppressed this spring.


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

 “It’s a day for announcements on COVID today, and while we wait to hear the strategy for ‘living with COVID’, the JCVI have released a statement concerning their advice for further vaccination for adults. Those reviewing the data from the UKHSA weekly reports might be a tad surprised to note the focus for a ‘spring’ booster restricted to adults of 75 and over and those living in care home settings. Given that the 65 -74 year old age group (at 6.7 million) is larger than the entire population aged 75 and older (5.7 million – source ONS population 2020), one might have imagined this might have offset the (not so much) lower hospitalisation rate in this age range when expressed in hospitalisations per 100,000 population. Regrettably, the data which support the assertion of a faster decline of booster effectiveness vs hospitalisation in the 75 and older age group is unpublished. To be completely convincing, it would be helpful for this information – enough, it seems, to drive policy – to be shared with those of us that are affected by the decisions made on our behalf. With community infection rate still stubbornly high, there is ample opportunity yet for another variant with higher case fatality rate to emerge before the proposed ‘autumn’ campaign – and if it does perhaps this advice may yet be regretted, given that it’s a long time to wait for autumn.”


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

“This is a sensible thing to do. We know that immunity contracts over time and that this is usually more pronounced in older people, who are also most likely to develop serious disease. Therefore, giving these people an additional boost to their immunity makes sense to help protect them disease.

“We never expected vaccines to provide long-term protection against infection, therefore ensuring that vaccine policy focusses on reducing disease burden is sensible, and this means focusing efforts on older people, together with other at-risk groups.”


Dr Peter English, Retired Consultant in Communicable Disease Control, Former Editor of Vaccines in Practice, past Chair of the BMA Public Health Medicine Committee, said:

“This is a very reasonable decision.

“We know that, after each dose of a Covid vaccine (at least up to dose 4, and probably further doses) the immune response is enhanced in several ways.

“The first is that antibody levels increase rapidly (are “boosted”). Antibodies can prevent infection by neutralising the virus before it can get into cells. They are very specific – they are most effective against the variants they were developed to counter; if the virus mutates, higher concentrations of antibody may be required to have the same neutralising effectiveness.  Reinforcing doses increase “avidity” – the strength with which antibodies bind to the virus’ antigens, increasing their effectiveness.

“Unless the immune system is triggered by exposure (to virus or vaccine), antibody levels gradually fall away. The concentration of antibodies will eventually fall below the level needed to prevent infection – especially if changes to the virus mean that higher quantities are needed for neutralisation.

“Reinforcing doses also enhance the immune system more broadly, increasing the cellular response (which includes T-cells). This helps or enables antibodies to be released more quickly on re-exposure, and a more rapid, vigorous and effective response to infection, so that infections are stopped early, usually before severe illness can occur. It also helps to broaden the immune response, so that the cellular immune response will better recognise closely related viruses (such as variants).

“The people being offered fourth doses are those in whom the vaccines are likely to have been least effective due to disease, immune-suppressive medication, or age (“immune senescence”). They are less likely to be as well protected by prior vaccination; and, if infected, they are more likely to be seriously ill if they encounter the infection. They are, therefore, the people who are most likely to benefit from this extra dose.”



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



Declared interests

Dr Peter English: “Dr English is on the editorial board of Vaccines Today: an unpaid, voluntary, position.  While he is also a member of the BMA’s Public Health Medicine Committee (and its chair until Oct 2020), this comment is made in a personal capacity.  Dr English sometimes receives honoraria for acting as a consultant to various vaccine manufacturers, most recently to Seqirus.”

None others received.


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