Saturday, June 5, 2021

Herd Immunity Through Vaccination ?

With no cure for Covid-19 virus found yet, the rapid mutation rate, contagious and infectious, the world's answer to stop the pandemic was to develop a vaccine for it.  Vaccines were developed at the speed of light, within a year compared to the norm of 10 to 15 years.  Not just with the conventional used of de-activated virus but another technology in the form of mRNA was also deployed.  So the answer the world has to stop Covid-19 pandemic or to make it an endemic instead is through herd immunity via vaccination.  The initial target of at least 70% of the population being vaccinated means achieving herd immunity.  This is the narrative so far but it just leaves too many questions with no concrete answers if anyone cares to do a deep analysis into it.


Firstly, let goes through some background.  Since the Spanish Flu in 1918 till now, the noticeable pandemics the world have gone through before Covid-19 were 2003 SARS, 2009 Swine Flu and 2012 MERS.  There were still some non noticeable by most people like 1957 A/H2N2 Influenza pandemic, and 1968 Hong Kong Flu to name a few.  In fact, except for countries that were affected by the 2009 Swine Flu and 2012 MERS, believed most would not remember those either.  Of those list of pandemics, believe none has ever experienced such a rapid mutation rate as compared to Covid-19.  To be precise, virus does mutate all the times according to the basic of life science -- living things react to changes to seek for survival, but not such a fast pace of mutation to a more or equal contagious variant as the original source.  In Covid-19 which was supposed to be first reported in December 2019 but globally started the infection in early 2020, within a period of less than 1.5 years, of equal or more contagious variants were detected in the UK, South Africa, Brazil and India.  On top of that there were also couple of other variants which were considered not so infectious.  While none of these variants are as deadly or more deadly than the original virus, that doesn't mean there won't be people dying from those.  People might not be killed directly by them but could be indirectly due to overloading of the healthcare system.  

Having said that, this means none of those in WHO, medical researchers, experts and specialists globally have ever experienced such a rapid mutation rate pandemic.  So is herd immunity via vaccination really workable since there isn't any past history or reference of success against a rapid mutation rate pandemic ?  In fact for the past pandemics mankind been through all without vaccination during the pandemic period and yet we managed to stop it.


Next, some background on vaccination.  Consider any virus infection can be divided into 4 states, naming Asymptomatic, Symptomatic, ICU and Death.  The naming of the 4 states is for any layman to understand the seriousness of the virus infection so it might not be the exact scientific term being used.  Asymptomatic as the name indicates meaning when the virus is inside the body, the natural immune system is able to detect, identify and destroy the virus without showing any symptoms to the person.  Symptomatic means all the symptoms like fever, cough, running nose etc all surfaced to indicate said person is sick, infected with virus.  ICU state means the condition has worsen and in need of intensive care in hospital.  Death state, don't think I ever need to further elaborate on.  

Covid-19 is not as fatal as SARS and according to statistic, the fatality rate is about 5% to 6%.  Hence, it only occupies about 6% among the 4 states.  While there isn't concrete statistic to show the exact ratio of the Asymptomatic, Symptomatic and ICU states, we could roughly state that for a person who is not being vaccinated the majority of the remaining 94% should be occupied by the Symptomatic and ICU states.  However, if the person is vaccinated (fully vaccinated) the Asymptomatic state would expand and occupying the majority of the 100%.  As the purpose of the vaccine is to prevent severity, you could expect the ICU and Death states will have a very low percentage.  Unfortunately, those can't get to 0% and that is reality since vaccine is not a cure.

Virus still can enter the body of a vaccinated person (not sure who that dude who started to give person the wrong impression that after vaccinated will not get infected, a thumb down to you !) just that it has higher chance of being detected, identified and destroyed by the immune system before it could advance to the Symptomatic state.  Infection doesn't mean must be in Symptomatic state, as long as the virus in Asymptomatic state is not being destroyed, it is considered as being infected.  The layman thinking that only through symptoms then can be considered as infected is unfortunately scientifically incorrect.

So, how herd immunity through vaccination comes into play ?  The principle is as more and more people are vaccinated, more and more people will have a widened Asymptomatic state which will have a higher chance of the virus being destroyed before they could advance to the Symptomatic state.  As such, nobody can feel like they are being infected as they are practically not sick.  This will reduce the contagious of the virus and prevent mass spreading.  This concept works perfectly for a dominant variant as through vaccination the immune system remembers this variant and as along as it enters the body, it will be able to detect and destroy soonest possible.  However, the big question is will it really work as expected in a rapid mutation rate pandemic whereby multiple contagious variants could enter the body at the same time ?


Another background, the Covid-19 vaccines we have by all the makers were developed based on the original source of the Covid-19 virus.  As virus mutates to another variant, there will be some changes, be it minor or major to the original strain.  This will give a possibility that the immune system will be unable to detect it.  This explains why the efficiency is being reduced when test against those 4 contagious variants.  In fact, we are registering at least 10% drop in efficiency against the variant that was first detected in India, the B1617 variant.

Now enters the first scenario.  The B1617 variant by now is no longer a kept secret that fully vaccinated people will not get infected, meaning the variant advances to the Symptomatic state.  To advance into the Symptomatic state with an expanded Asymptomatic state suggests the virus is able to escape detection though not 100% but still a percentage that is of great concern.  In Symptomatic state, it will continue the infection to another person.  Another perspective view is the variant breakthrough the protection from the vaccine.  

The second scenario.  What if multiple variants among the 4 enter the body ?  The immune system fails to detect one is the scenario as mentioned above.  If the immune system fails to detect more than 1 variants what will be the outcome ?  Failing to detect the variants meaning giving times for them to incubate.  The Covid-19 and its variants are known to have an incubation period of as long as 21 days.  That substantial amount of times could lead to a lot of things to happen inside the body which we can't even see with our naked eyes.  They could finish the incubation period and advance to the Symptomatic state.  They could also mutate among themselves to another variant and advance to the Symptomatic state.  The big concern is the later case as the mutation could result in a more deadly or more contagious variant that drastically reduce the efficiency of the vaccine.  There has been talk about virus-x and this monster variant could be that virus-x.  As such the function of the vaccine has now became a double-edged sword in this rapid mutation rate pandemic.  The function of the vaccine is to prevent severity but on the flip side, it also becomes a platform for mutation of variant.  The so-called herd immunity from the vaccine no doubt will increase the number of platforms for further mutation.  With increases in the number of platforms and the correct conditions, it will just only take one successful mutation and the so-called herd immunity will create another pandemic.


Some might question whether the double-edged sword scenario can even exist.  Since there is no precedence it can happen, it also doesn't have precedence it cannot be happened.  The only way to know just like any scientists do is to carry out lab experiment.  Concurrent experiments can be carried out with batches of lab rats, one batch with 100% lab rats vaccinated, another batch with 90% of them vaccinated, third batch with 80% vaccinated and final batch with 70% vaccinated.  Multiple variants are then injected into a few of those vaccinated lab rats and observe them for 1 to 3 months (more than enough time frame to cover the 21 days incubation period).  At the end of the experiment, we should have a clearer picture that whether herd immunity through vaccination really works as per theory and at the same time have a better statistic of which percentage level of vaccination can be really considered as herd immunity if it works.  If the herd immunity concept doesn't work out, experts, specialists and global leaders better have another plan to combat the pandemic.  Question is has any of the medical researchers, experts or specialists carried such an experiment before suggesting herd immunity through vaccination being carried out ?  


To summarize the above lengthy analysis :-

1. It is the first time human beings experienced such a rapid mutation rate (of equal or more contagious variants) pandemic.

2. Herd immunity through vaccination has no precedence or reference it works on rapid mutation rate pandemic.

3. Herd immunity through vaccination could potentially becomes a double-edged sword in a rapid mutation rate pandemic.  It serves to prevent severity and at the same time creates more platforms for further mutation (to a more deadly or contagious variant) which could be the building block of another more damaging pandemic.

4. If the herd immunity through vaccination fails, what's the next plan to stop the pandemic ?



Singapore Covid-19


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