Of Herd Immunity, Plasma Therapy, Vaccines And Drugs For COVID-19!
In view of the worrying surge of SARS-CoV-2 (COVID-19 or the new Coronavirus)
the world over with the worst affected country USA having a second wave and in
India, Brazil and others the infections going unabated desperation for
treatment measures is growing all the time. Besides, the World Health Organization
(WHO) has been consistently maintaining that possibility of having a vaccine is
at least one and half years away. The WHO has also maintained that there is no
proven cure for COVID-19 so far. The basic reason that justifies such kind of
desperation is that this virus is far more dangerous than the recent viruses,
its mortality rate almost 10 times higher than those. The virus has caused
havoc on planet Earth before the humans came to understand and know much about
it. Therefore, various issues concerning herd immunity, plasma therapy,
development of vaccines and use of repurposed drugs are being discussed and
experimented continuously all over the globe.
The term ‘herd immunity’ basically means that if most part of the
population becomes immune to a particular infectious disease then they will get
indirect protection than those who are not immune to it. For example, if 80% of
the population gets immunity then four out of five people won’t get sick
despite coming into contact with infected people. At least 70 to 90% immunity
will be required for effective herd immunity that can keep the virus under control.
The problems come when talking about how to achieve this herd immunity. There are
two ways of achieving herd immunity: with precautions and social norms not
being followed strictly a large portion of the population is likely to get infected
and if it is at least 70%, the population can get herd immunity, and secondly,
simply through the development of a vaccine. In the first case the cost of a
large number of people getting infected will be very heavy and high in terms of
loss of lives. In India and other populous countries large chunks of population
are susceptible or exposed to the virus, and to achieve herd immunity through the
first way is not advisable at all. Therefore, the only way to achieve this
would be through a developed vaccine, and till it is ready for mass use the
infections must be kept under control by enforcing strict social distancing and
other norms.
Plasma Therapy has been emerging as a very positive development for
treating serious COVID-19 patients where the blood plasma is collected from
recovered Coronavirus patients is injected into them and the anti-bodies contained
in that helps curing them. In India, this therapy is being practiced with good
results; plasma banks are being established in Delhi, Haryana and Maharashtra
among others with requests to recovered patients to donate plasma. In fact, the
Health Minister of Delhi who got seriously ill with COVID-19 recovered finally
with this therapy.
The WHO has stipulated very stringent procedures for development of COVID
Vaccines: the produced vaccine has to go through three rigorous phases of
clinical trials with increasing numbers of human volunteers given doses before
being declared safe for use which would take several months apart from the
months needed for mass manufacture and distribution. At the moment there are around
100 vaccine candidates the world over including seven firms in India with a few
of them already approved for clinical human trials: the Oxford vaccine
developed in the United Kingdom currently in the third phase of trial; CureVac
from Germany approved for clinical trials; a Russian COVID vaccine claims to
have successfully completed the three phases of human trial and now ready for
mass production and at least two vaccines on trials in India with the first-ever
Indian vaccine candidate Covaxin by Bharat Biotech getting approval from the Drug
Controller General of India (DCGI) for human trials. In fact, the Indian
Council of Medical Research (ICMR), the apex medical body, created a controversy
recently by directing the stakeholders to fast-track Covaxin making it ready
for mass use by 15th of August 2020 which was promptly rebuffed by
the Government of India. It is to be emphasized here that even if a vaccine is
finally approved for mass use its effectiveness will still be under scanner,
because every vaccine mutates often and so, there is no guarantee that a
vaccinated person won’t get COVID-19 in possibly a year or more.
As an integral part of the desperate search for COVID cures or treatments
various repurposed drugs have been tried continuously for treating the SARS-CoV-2
virus. Hydroxychloroquine, a drug used successfully for treatment of malaria in
India, was first tried on the infected medical fraternity leading to a spree of
exports by India on demand from various countries including the US. However,
finally, the WHO has discontinued its trials in July 2020 for reasons of side
effects and safety. Antiviral drug Favipiravir, originally produced in Japan to
fight influenza, under the name of Fabiflu distributed by Glenmark Pharma was
officially approved in June 2020 to treat mild to moderate Corona patients in several
countries. However, its side effects are under scanner and the DCGI has only
approved emergency use with prescriptions.
The WHO has been very hopeful on the efficacy of a corticosteroid called Dexamethasone
as a life-saving medicine for critically ill Corona patients based on the clinical
trial in the United Kingdom. Since Dexamethasone is basically an anti-inflammatory
drug its use is only to cut mortality rates in patients requiring oxygen or
ventilator support. Another antiviral drug, Remdesivir (Covifor) produced by
Gilead Sciences is so far the only accepted medicine for treatment of COVID-19
given approval by the Food and Drug Administration (FDA), and recently
distributed in India too that led to a craze with reported black marketing. However,
this medicine not for public purchase in chemists, and only for supply to hospitals
for doctors to prescribe under discretion for serious COVID patients. Its overall
safety is yet to be proved though.
Desperate times call for desperate measures. And the quest for a possible
cure for the killer virus goes on. In the meantime, humankind must adapt to the
new normal following stringent social distancing norms and other precautions,
for at least a year more, hopefully.
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