Herd Immunity and Covid-19
Introduction
:
Now-a-days it
is our regular fight against the danger
of infection by the most contagious
disease Covid-19 ; We fight it at
all levels, at personal level, by maintaining social
distancing & proper sanitization, at
local level & also at national level by observing
various measures instructed by
the Authorities ; In this context we sometimes hear the term ‘Herd Immunity’ ; Recently the British Prime Minister Mr.
Boris Johnson also mentioned this term
as a good measure of fighting against Covid-19
; What is this ‘Herd Immunity’ ? How can
it be achieved ? How far it is suitable
to fight
against Covid-19 ? To the
non-medical general people like us it
will be convenient if we discuss it
briefly in very simple terms ;
What is Herd Immunity ?
‘Herd Immunity’ is the term used for social or group
immunity ; That is, it is the immunity
at social level ; When most of the
persons in a given group or society gets immune or resistant to a particular
virus which is contagious & normally
spreads from person to person, the group
or society can be said to have obtained herd
immunity against that virus ; In that case if one person gets infected, it is much less likely that he will be able to unknowingly spread it easily to
another person ; In this way, the elderly persons, pregnant women, children or
persons suffering from other diseases of
that society, who are less or not at all
immune to that virus, are saved ; The Critical Percentage or the
‘Threshold Limit’ of population which must be immune to stop spreading a virus
is different for different diseases ; As for example for the disease of
Measles, this threshold limit is 95%,
that is, about 95% of a
population have got to be immune to achieve herd immunity against that virus
; However, for ‘SARS-CoV-2’ or
Novel Corona Virus experts predict at least 70 % of the population need
to be immune to the virus in order to achieve herd immunity ;
The Various Ways of Achieving
Herd Immunity :
Herd Immunity or group immunity can be achieved in two
ways, by a)
Natural Way & by b) Vaccination ;
a)
Natural
Way – Natural immunity occurs when you get immune to a particular disease by contracting
it yourself, that is, contracting it within your own body ; In that case the anti-bodies created in your body to fight for that disease remain to be
present in your body even after your recovery from that disease and protect you
from that disease in future also ; In
this way when majority of the people in your society suffer from this disease,
a natural immunity at social level or herd immunity in your society is built up ; But it is not preferable for
the most obvious reason that to obtain herd immunity in this way each
person of the majority number of people has to suffer from the
disease individually, which may turn up
to be much costly to the society in terms of number of death toll and excessive
pressure on medical infrastructure ; Besides, one
may not know if one has contracted the illness or if one is immune to it ;
b)
Herd
Immunity by Vccination - If the appropriate vaccine for that particular
disease is already available in sufficient numbers in that society, each of the majority number of
persons, may get vaccinated individually and in this way
herd immunity can also be obtained ; That process is much safer but, only if
the vaccine is available ;
Herd
Immunity against Covid -19 :
However,
there are many reasons why herd immunity is not suitable to stop
spreading of
this Novel Corona Virus ; The main reasons
are as follows :-
·
Vaccinations are the safest way to
obtain herd immunity in a given
population, but no Vaccine for Covid-19 has yet been
discovered ;
·
The research for any anti-viral drug is also
only going on but still not in hand ;
·
Doctors do not know exactly why some
people who contract this illness suffer from serious side effects while the others do not ;
·
Hospitals and healthcare
infrastructure may get overburdened if many people contract Covid-19 at the same time ; Sometimes it may go
well beyond the control of the
Government ;
Indian Context :
·
As the density of population in our
country is very high, especially in urban slum area, coupled with unhealthy living conditions, it may not at all be suitable to risk our
population in trying to obtain herd immunity by natural way ;
·
To obtain herd immunity by vaccination is not also possible at this
moment as no vaccine or any antiviral drug has yet been discovered ;
·
Hence, in our country, only
maintaining the Social
Distancing and proper
Sanitization at all levels remain
to be the only way out at this moment to fight against this Novel Corona Virus
;
Resources :
·
‘What is Herd Immunity and Could it Help Prevent
COVID-19 ?’
·
‘Is Herd Immunity Our Best Weapon
Against COVID-19 ?’
-
By
Jillian Monk, May 5, 2020
(www.discovermagazine.com) ;
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