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The week 6 national Influenza and COVID-19 surveillance report from Public Health England (PHE) was published yesterday and provides data on national seroprevalence of SARS-CoV-2.
Prof Paul Hunter, Professor in Medicine, The Norwich School of Medicine, University of East Anglia, said:
“The antibody data contained in the “Weekly national Influenza andCOVID-19 surveillance report Week 6 report” covers analyses on blood donations up to week 4 (week ending 31st January). From figure 53 it looks like the latest estimate of seroprevalence (the proportion of people who test Antibody positive) by age group was for the week ending 24th January.
“This seroprevalence data is an indication of the proportion of people who have had either a previous natural infection or vaccination. This infection may not have been recent. Also this proportion will be an underestimate as some people will have already lost antibody especially if they had their infection several months ago.
“Having said that it is notable that the prevalence has increased in recent weeks in all age groups reflecting the very high infection rate in January. And although the prevalence in the 70+ age groups has increased more than in most other age groups it is only when you compare this with the PCR prevalence also published today by ONS in its COVID-19 infection survey that the significance of this increased seroprevalence becomes clear. From the ONS report no firm conclusions about the impact of vaccination can be drawn but it is clear that during most of January, infection rates were lower in the 70+ age group compared to all other age groups. So for Ab prevalence to have increased in this older age group as much as it did, immunization must have played an important role.
“That Ab prevalence in this group was still only about 10% is nothing to worry about as we know it can take a while for older people to develop antibodies to immunisation. I would expect Antibody prevalence to increase substantially in the older age groups over the next few weeks.”
Prof Richard Tedder, Senior Research Investigator in Medical Virology, Imperial College London, said:
“The observation that the elderly age group are increasingly seropositive for antibody to the coronavirus, using a relatively insensitive assay such as EuroImmun, is nevertheless comforting, indicating a demonstrable impact of the government’s targeted immunisation for the elderly. It is however necessary to be careful in extrapolating from a serological reactivity induced by immunisation to actual protection against infection and resulting protection against illness. That said these observations are important and ‘pointing’ in the right direction. It also demonstrates the value of undertaking post immunisation antibody testing as a routine exercise.”
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www.sciencemediacentre.org/tag/covid-19
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