RE: Rns for Mologic antibody test -merchant3 Sep 2020 13:16
"- the Mologic IgA, IgM and IgG COVID-19 Triple Anitbody Test. This is a Lateral Flow Assay POC test. This was the one CEd by Mologic in June but which has just been CEd by ODX under the Visitec label and is the subject of the RNS this morning."
From the lancet today:
"The article, by three researcher from the MRC Biostatistics Unit at Cambridge, University Hospital Wales in Cardiff, and St George’s, University of London, is here (pdf). And here is an extract from a summary on the MRC Biostatistics Unit’s website.
https://www.bmj.com/content/bmj/370/bmj.m3364.full.pdf
Seroprevalence surveys estimate the proportion of the population that have previously been infected with a virus by measuring the presence of antibodies produced to fight off the virus. This is important for calculating severity measures such as the hospitalisation rate and fatality rate, as well as to understand the impact of public health policies, such as social distancing and mask wearing. They also inform our progress towards herd immunity, and the likelihood of a “second wave” of infections. Large-scale UK seroprevalence surveys have generally provided low estimates of virus spread, suggesting that 15% of those in London and only 4% of those in the south west and south east of England have been exposed to the virus.
However, there are several reasons why these surveys may not capture all those who have developed an immune response to the virus. There are several different classes of antibodies. Seroprevalence surveys typically only measure IgG and sometimes IgM antibodies, which represent the dominant antibody classes in the bloodstream. They do not typically measure IgA antibodies, which represent the main antibody class in mucous secretions, including saliva and the protective fluid around the eyes, respiratory tract, and digestive tract. As the main site of viral entry into the body is the respiratory tract, failure to measure IgA antibodies may result in false negative tests. A previous survey in Luxembourg found IgG antibodies in 1.9% of individuals, whereas IgA antibodies were found in 11.0%, over five times as many. Another survey of local residents in Ischgl, Austria used a combination of IgG and IgA antibody testing. Positive antibody tests were obtained for 42.4% of residents in Ischgl, far higher than other population-based surveys of infection hotspots. Additionally, most large seroprevalence surveys have been based on blood samples only. In a survey of UK healthcare workers, 15% of those tested for IgG, IgA and IgM antibodies provided a positive saliva test but a negative blood test."
From the PDF - "mucosal and bloodborne immune responses
may provide complementary information crucial for
accurate assessment of viral exposure in both
individuals and populations"
BOTH NEEDED
Aberdeenman
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