Coronavirus antibody prevalence falling in England, REACT study shows (Imperial college and Ipsos MORI, 27th October)
N = 365,000 antibody tests
Positive tests = 17,576
30% of whom did not report any COVID-19 symptoms
20 June and 28 September
Three rounds
Decline between rounds 1 and 3 in all age groups
Decline was largest in people who didn’t report a history of COVID-19
Asymptomatics
Dropped by 64.0% between rounds one and three
Antigen diagnosed group
Decrease of 22.3% between rounds one and three
Overall decline
Percentage testing positive, 6.0% to 4.8% and then 4.4% (a 26.5% reduction across the study period)
All areas of the country and age groups, but higher in London (9% at round 3)
But not in health workers
Decline was largest in people 75 and older
Professor Paul Elliott
Our study shows that over time there is a reduction in the proportion of people testing positive for antibodies.
Testing positive for antibodies does not mean you are immune to COVID-19.
It remains unclear what level of immunity antibodies provide, or for how long this immunity lasts.
If someone tests positive for antibodies:
they still need to follow national guidelines including …
social distancing measures
getting a swab test if they have symptoms
and wearing face coverings where required
Implications for immunity
SARS, 2002 – 2003
8,000 infections
774 deaths
Guangdong, southern China
Toronto
Hong Kong
Taipei, Singapore
Hanoi
SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls (Nature 15th July)
Memory T cells induced by previous pathogens can greatly influence future infections
Individuals convalescing from COVID-19
n = 36
All had N protein recognising T cells
Patients who recovered from SARS (One, 2003)
n = 23
Possess long-lasting memory T cells, reactive to the N protein of SARS-CoV
These have lasted for 17 years
These T cells displayed robust cross-reactivity to the N protein of SARS-CoV-2
We also detected SARS-CoV-2-specific T cells in individuals with no history of SARS or COVID-19 (n = 37)
In some people with no previous SARS one or two, or exposure to contacts
SARS-CoV-2-specific T cells in uninfected donors exhibited a different pattern of immunodominance
Targeting different proteins on the N protein
These proteins are highly conserved in animal betacoronaviruses
But have low homology to ‘common cold’ human-associated coronaviruses
So
Infection with betacoronaviruses induces multi-specific and long-lasting T cell immunity against the structural N protein
Vaccine, early months of next year, Matt Hancock
Oxford, AstraZeneca, AZD1222
30 million doses under UK manufacture
Roll-out first half of 2021
Some people vaccinated 2020
Immune response similar across all age groups
Strong immune response in elderly
Encouraging to see immunogenicity responses were similar between older and younger adults (AZ)
Lower levels of side-effects in older adults
Elderly usually have a reduced immune response (e.g. influenza vaccine)
Antibodies and T-cells
Brazil, India, South Africa, UK, US
Medicines and Healthcare products Regulatory Agency
Food and Drug Administration
Art work from Charles
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