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expert reaction to media reports suggesting early phase II data (not yet published) suggests the Oxford COVID-19 vaccine induces an immune responses in older as well as younger adults

There have been reports that early phase II data for the Oxford COVID-19 vaccine trial suggests similar immune responses between older and younger adults.


Prof Stephen Evans, Professor of Pharmacoepidemiology, London School of Hygiene & Tropical Medicine, said:

“In order to comment properly on this we need to see the data.  It is encouraging that the investigators suggest that the immune responses measured in the blood seem to show efficacy both above, as well as below, age 70.  The later phase trials are needed to see if the immune responses translate into clinical efficacy in preventing infection.  These will involve much larger numbers and it is wise to not be too optimistic until those trials have completed.

“Immunogenicity measures antibodies in the blood which may indicate (but do not guarantee) likely protection from the virus multiplying in the body.  We need to see the data before concluding that the responses were “similar”.  There needs to be a sufficient number studied over a wide range of ages.  “Reactogenicity” is the reaction of the body to the vaccine in terms of things like, soreness of the arm, redness, fever and possibly nausea or other things that can occur soon after any vaccine is given.  Usually these effects disappear within a few hours.

“There is often, but not always an association between immunogenicity and reactogenicity, but this varies between vaccines.  If the body over-reacts, which it can do in very rare instances, then that obviously is not good.  Having a high fever that lasts more than a few hours is an example.  The reactogenicity will often be related to the dose of the vaccine, and studies carried out in the first stage of development of a vaccine will result in choosing a dose that does not cause too much reactogenicity.”


Prof Robert Read, Head of Clinical and Experimental Sciences within Medicine at the University of Southampton, and Director of the NIHR Southampton Biomedical Research Centre, said:

“Previous data had shown the vaccine induces an immune response in younger people – it sounds like there is early data suggesting the same happens in older adults, which would be reassuring, but we haven’t seen the data yet.  This is very encouraging, but we still need to wait a little longer for information on protection from natural disease and overall safety in ‘field trials’.  The fact that reactogenicity – adverse events after vaccination, such as sore arm/fever etc. – is said to be relatively low in older adults is also very reassuring.”



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



Declared interests

Prof Stephen Evans: “No conflicts of interest. I am funded (one day per week) by LSHTM. They get funding from various companies, including Astra Zeneca and GSK but I am not funded by them, I have no involvement in obtaining funding from them and I am not an investigator on any grants obtained from them. I am the statistician to the ‘meta-Data Safety and Monitoring Board’ for CEPI. I am paid for my attendance at those meetings and will be paid expenses for travel if that occurs.”

Prof Robert Read: “I don’t have any conflicts.”

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