Covid 19 attenuated

Whenever a virus jumps from its natural host to another host (like humans), it tends to be virulent during the first few days, chiefly because the new host doesn’t have specific protective immunity against the novel virus. This results in higher mortality during the first few days or weeks. However, innate immunity provides protection to most individuals and that’s the reason why all of them aren’t killed. However, very soon the new host develops acquired immunity against the virus. And, in course of time – when a sizable percentage of the population has been exposed to the virus, herd immunity develops, which gives protection to the masses. Moreover, the virus also loses its initial virulence as it adapts itself to its new host and endeavours to establish a more commensal relationship with the host – for its own survival and propagation as it very well “understands” that killing the host will also kill it. COVID 19, which had an initial mortality rate much less than that of H1N1, SARS or MERS-CoV, has already reached this adaptive phase. 2009 H1N1 now causes mostly mild infections. COVID 19 – a much milder disease than H1N1 – will cause still milder infections just like the prevalent Corona viruses in our region. And, thanks to our warmer climate, it will hopefully not spread in our areas.

However, taking into consideration the rapidity with which COVID 19 is spreading in the Northern hemisphere, if it manages to reach the Southern hemisphere, where winter will set in soon, it may spread there, too. The virus may thrive in the southern hemisphere for the next 6 months and resurface in the northern hemisphere in October-November. What will actually happen only future can tell. No previous novel Corona viruses had spread so fast and so widely (a characteristic that is classical of Influenza A viruses). However, our only hope is that COVID 19 will become milder over the months just like 2009 H1N1, which is still there in circulation even after 11 years of its origin.

So, are we going overboard to prevent its spread? The answer is ‘NO’. We must take all preventive measures to reduce the human to human transmission of this virus, specially in a populous country like India, so as to flatten the curve of the occurrence of an epidemic. Our aim is to flatten the peak of this curve as far as possible. Otherwise, hospitals will soon overflow with COVID 19 infected patients and suspects, which will be a huge burden on our healthcare system and will drain out our limited resources very soon – as is happening in Italy.

And, is there any specific treatment for this virus? So far, no organization or guidelines have advocated any antiviral to treat this infection. However, some have found that protease inhibitors, an anti-HIV drug, may be effective against COVID 19 (it was also used against SARS-CoV), since such Corona viruses have some protein inserts that are similar to those of retroviruses like HIV. Some have also advocated the use of Chloroquine, an anti-malatial drug, to treat COVID 19. But, till now it’s too premature to advise any specific therapy against this virus, which is barely 3- months old. All respiratory viruses, except Influenza viruses, are treated conservatively. Hence, standard supportive treatment – as approved for all viral infections affecting the respiratory tract – is advised for COVID 19 infections, too, categorized according to the severity of infection.

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