BACK

Research letter looking at spike-antibody level waning after second doses of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines

This article was published on
July 22, 2021

This explainer is more than 90 days old. Some of the information might be out of date or no longer relevant. Browse our homepage for up to date content or request information about a specific topic from our team of scientists.

A research letter published in The Lancet looks at spike-antibody waning after the second dose of either the Pfizer-BioNTech or Oxford-AstraZeneca COVID-19 vaccine.

A research letter published in The Lancet looks at spike-antibody waning after the second dose of either the Pfizer-BioNTech or Oxford-AstraZeneca COVID-19 vaccine.

Publication

Spike-antibody waning after second dose of BNT162b2 or ChAdOx1

Not peer-reviewed
This work has not been scrutinised by independent experts, or the story does not contain research data to review (for example an opinion piece). If you are reporting on research that has yet to go through peer-review (eg. conference abstracts and preprints) be aware that the findings can change during the peer review process
Peer-reviewed
This work was reviewed and scrutinised by relevant independent experts.

What our experts say

Context and background

Resources

Media briefing

Media Release

Expert Comments: 

Prof Eleanor Riley

The decline in antibody concentrations in the immediate few weeks after vaccination is exactly what I would expect to see. In the absence of ongoing antibody synthesis, antibody concentrations decay at a predictable, exponential rate. This is not necessarily a problem.

The two key parameters are firstly,  the minimum concentration of antibodies required for protection and secondly, how quickly antibody concentrations can increase again in the face of infection (the so-called memory response). This study does not answer these questions and, indeed, they are perhaps the most crucial questions we need to answer in order to determine the need for booster doses. As the authors themselves say “the clinical implications of waning antibody levels are not yet clear and it remains crucial to establish S-antibody thresholds associated with protection against infection and disease”.

mRNA vaccines such as the Pfizer/BioNtech vaccine are designed to induce high concentrations of antibodies. Viral vectored vaccines (such as the Oxford AstraZeneca vaccine) tend to induce lower antibody response but stronger T cell responses. The differences in antibody concentrations induced by the two vaccines is thus not surprising and not a cause for concern.

However, emerging evidence suggests that antibodies are particularly important for blocking infection and preventing onward transmission of the virus whereas T cells may be particularly relevant for preventing severe disease and death. Maintaining sufficient antibody concentrations to reduce transmission will be important to limit the amount of circulating virus but maybe less important for protection against severe disease.

Q&A

No items found.