National

Covid-19 variant can evade body’s immunity with or without vaccination: Immunologist

Vinson Kurian Thiruvananthapuram | Updated on May 26, 2021

Satish Ranjan, molecular immunologist and Covid-19 scientific consultant

But the theory that inoculation enhances the disease is unconvincing, says Satish Ranjan

The theory of vaccination-induced antibody likely enhancing disease in vaccinated individuals, reportedly propounded by French virologist and Nobel Prize winner Luc Montagnier, is less than convincing, according to a leading Germany-based molecular immunologist and a Covid-19 scientific consultant.

Luc Montagnier is reported to have called mass vaccination against the coronavirus ‘unthinkable’ and a historical blunder that is ‘creating the variants’ and leading to deaths.

He had further talked about ‘antibody-dependent enhancement’ and said that ‘it is the antibodies produced by the virus that enable an infection to become stronger.’

Track infection ratio in vaccinated vs non-vaccinated: Satish Ranjan

Mutation, a normal phenomenon

Mutation is a normal phenomenon in coronavirus, and it has produced several variants more transmissible than before and which also escape immunity, says Satish Ranjan, molecular immunologist and Covid-19 scientific consultant.

This is evident from the increased number of moderate to severe cases in the second wave in India compared with the first.

During the first Covid wave, a large section of the population was infected, and immunity developed as revealed by the sero-prevalence analysis in many cities. But a larger number of people fell sick in the second wave signalling how emerging variants escaped immunity gained after virus infection.

First Covishield jab triggers ‘good levels’ of antibodies

So, immune escape by variants can happen even in the absence of vaccination, likely driven by naturally produced antibodies. It will be a much better option to determine emerging variants from vaccinated and non-vaccinated individuals to better understand the efficacy of vaccines.

Disease progression in vaccinated and non-vaccinated will not vary to such an extent it poses serious threat to vaccinated individuals. A better understanding of disease pathophysiology will guide us to better treatment, reducing the severity of disease in both vaccinated and non-vaccinated groups, Ranjan said.

Blood capillary damage

It is very important here to understand what antibody-dependent enhancement is. “We need to first appreciate the Covid-19 disease pathophysiology after infection in non-vaccinated individuals,” Ranjan wrote in an email to BusinessLine.

In non-vaccinated individuals, immune cells produce antibodies 4-5 days after coronavirus infection. In most cases (80-90 per cent), the viral load will clear up and patients recover, Ranjan, who was recently appointed as Scientific Advisor to Government of Nagaland, said.

In some cases, the disease progresses and leads to damage of blood capillaries in lungs, generating enhanced risks of blood clotting due to endothelial damage. This may also lead to activation of immune cells leading to a cytokine shower in moderate phase and cytokine storm in severe cases.

These moderate to severe cases are also characterised by breathing problems and may require intensive oxygen support. The role of antibodies produced after 4-5 days of infection in the damage of blood capillaries in lungs is known and this is called ‘antibody-dependent enhancement.’

Vaccine-induced antibodies

The immune disorder wherein antibodies recognise some proteins in the blood capillary wall as viral protein or viral-like protein and attack capillaries leading to their damage and enhancing the disease happens even in the absence of vaccine-induced antibodies in naturally infected individuals.

In a majority of vaccinated individuals, vaccine-induced antibodies will provide protection and will clear the viral load during acute phase (initial 3-5 days) providing enhanced protection. But in some others, the disease can progress just as it does in non-vaccinated individuals after natural infection.

“This is one of the reasons why plasma therapy may not work in moderate and severe cases. The viral load in these cases may range from low to negligible. Enriched antibody in plasma may not be of help here; it may even lead to antibody-dependent enhancement and adverse reactions in some cases.”

Assess thrombomodulin levels

“In order to determine the extent of blood capillary damage in the lung, I propose that we determine the plasma levels of thrombomodulin, an integral protein of endothelial membrane in blood vessels,” Ranjan said.

Enhanced levels of the protein correlate with the extent of blood capillary damage, reflect clinical conditions better and reveal onset of capillary damage. No antibody therapy may work any further in these cases.

Rajan recalled the Nobel Laureate claiming that, ‘it is clear that new variants are created by antibody-mediated selection due to vaccination.’ “But we know already that vaccine can induce immunity against the disease and provides an opportunity to the virus to mutate and escape immunity.”

Published on May 26, 2021

Follow us on Telegram, Facebook, Twitter, Instagram, YouTube and Linkedin. You can also download our Android App or IOS App.

This article is closed for comments.
Please Email the Editor

You May Also Like