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New Delhi:The presence of antibodies indicates previous exposure to the SARS-CoV-2 virus but may not always translate into protection against the disease, say scientists, citing imponderables such as what kind of antibodies, how many and how long they last.
As worries over India’s COVID-19 spike mount – the country added 75,809 cases on Tuesday to take its tally to 42,80,422 – scientists are grappling with the pivotal issue of antibodies and trying to understand how they impact on the progression of the disease.
But the jury is still out there with several studies and hypotheses but no consensus yet. The only thing that can be said with any degree of uncertainty is that antibodies are a sign the person has already been infected with the novel coronavirus, the scientists said.
Immunologist Satyajit Rath said he would prefer to “wait and see” where the evidence goes.
Antibody presence in itself tells us nothing about disease progression in individuals, said the scientist from New Delhi’s National Institute of Immunology (NII).
There are neutralising antibodies (nAbs) and also ‘simple’ antibodies. While nAbs produced against the novel coronavirus can block its entry into the host cell, other antibodies are also generated against many parts of the virus, added Vineeta Bal from Pune’s Indian Institute of Science, Education and Research (IISER).
The ‘simple’ antibodies are an indication of host response to viral presence but are not that useful to stop further spread of the virus, Bal told PTI.
“Simple presence of antibodies is a clear indication of previous exposure to SARS-CoV2 but does not necessarily guarantee protection from the disease in the absence of neutralising antibodies,” the immunologist added.
“Presence of nAbs in sufficient concentrations and for longer period is the most likely indicator of protection of the individual from next exposure leading to illness i.e. COVI