COVID-19, The King of 2020 and Emperor of 2021 holds sway

May 2020 the Koyambedu Market in Chennai emerged as the epicenter of the COVID-19 outbreak. A flower vendor was identified as the index case whose brother was a taxi driver and possibly the source for her infection.img01

The Koyambedu marketplace is huge with  retail vendors travelling from a radius of 100 kms and customers from atleast a radius of 10 kms. Man became the vector.

The virus fanned out to the neighbouring districts of  tiruvallur kancheepuram and vellore. It was a slow and steady spread during the first wave as the incubation period was longer.


While there was no question about the infectivity of the virus, what remained a puzzle was that some members of a household got infected while some were spared. There were anecdoctal stories of travelling in the same car seated adjacent to each other yet being spared.

Could this be then dose related? A critical dose needed to acquire infection and host related factors to determine the course of the infection.


The most common mode of acquiring infection happened when masks were down and bonding happened over food .The exposure time and possibly the dose required to cause infection were achieved. However again not all got infected.


The virus host interaction seemed fascinating and alarming. Fascinating because for a respiratory virus SARS COV-2 was wrecking havoc on  non respiratory organs. There were also no visible signs of the havoc being wrecked, an alarming situation as the progression to severe disease was sudden and quiet.


 The virus was travelling through multiple pathways to cause a spectrum of disease which probably explains why different modalities of treatment worked.

 Written by Dr Padma Srikanth

Acknowledgements to Shruthi.V, for the drawing