Busting the myths around OPV
I believe I live in a wonderful society, it’s so diverse and tolerant; anyone can get up and say whatever they want and as long as it isn’t blasphemy, people would listen to it. However every now and then something comes up which is so flabbergasting in nature that even a passive soul as me can’t help but cry “Where on earth did that come from!”. Moving on then to the issue at hand, this time it was from a highly respectable persona (no sarcasm) whose sincerity and commitment is out of question. Anyhow that does not change the fact that some of the assumptions made by respected writer are just too full of implications, to be ignored.
The recent article of Najma Sadeque regarding safety issues, associated with Oral Polio Vaccine (OPV) was very liberating in the beginning; most of us agree that plenty of time governmental bodies fail to take into account the consent or needs of public. But after that the ride got a bit bumpy, so as a virology student who has studied this particular vaccine in quite some detail, I felt obliged to clarify a few things. So first things first, let’s clear the one big doubt about these vaccines which stems from the statement that it’s a live vaccine.
Since the assumptions made require a bit of technical explanation, so let me take you down the rabbit hole and explain what a live vaccine is? We all know the idea of a vaccine; you take a germ (virus, bacteria etc.) and then you either kill it or weaken it sufficiently(remember this word), after that you put it back in the body for your built-in defence system to prepare defences against it, since it’s a killed or sufficiently weakened version of the germ therefore it causes either little or no disease in the receiver. What is gained by all this procedure is induction of a state of preparedness against that particular germ, so that when the real germ comes in, our body is ready to react?
Same goes for the polio vaccine, OPV contains a crippled version of polio virus which is sufficiently weakened and therefore unable to cause disease .You give it to a child, his/her body examines it and makes arrangements to ensure that when the real thing comes then it would be taken care of instantly. Now just to clear the doubts once and for all I will briefly explain how this sufficient weakening is ensured. Just like all living entities, viruses have a genome made up of RNA or DNA, this genome dictates what sort of organism will be formed, just like your genome decides what hair colour or what skin tone you will have. It’s like the blue prints of a building or schematics of an engineering project, or source code of computer software. Now just like a program can’t do anything other than what its source code dictates, a virus can’t do anything other than what its genome tells it to do. What the scientists did a few decades back was that they introduced a change in the genome of polio virus, it’s like intentionally inserting a bug in a program or messing up the blue prints of your building a bit (say remove the main door or something). Now when they did that, the virus became mal-functional, it could still infect a person and reproduce in them, but it was unable to cause any significant damage.
So all things considered, ‘YES’ there is a living virus in there but it’s a defective version, a variant which induces protection rather than disease. The fact of the matter is that occasionally recipients of vaccine do develop VAPP(Vaccine-Associated Paralytic Polio), so how do we justify that? Then there is the policy of United States where OPV use has been discontinued……why?
Well it’s not as simple as it seems but hear me out, if you want logical answers rather than conspiracy theories .The defective strain in vaccine infects a person and multiplies in it, and when it does that it multiplies its genome and during that multiplication it might accidentally fix the error or mutation in its genome. It’s like randomly modifying source code of your program rather than educated debugging; one in a million times you might end up fixing the bug. The question is that how often that does happens?
Make a guess? One in every 2.4 million.
While before the vaccination strategy was applied, more than 21,000 paralytic cases reported in the U.S. in 1952……in ONE YEAR!
And after that, from 1980 through 1994, 303 million doses of OPV were distributed and 125 cases of VAPP were reported, for an overall risk of VAPP of one case per 2.4 million doses. So, suit yourself, what will it be, abandon vaccine and forsake all or embrace it and sacrifice lowest possible numbers.
And what if I told you that even, that low number can be avoided and hence eradicating Polio completely?
Incidentally, the answer to this collateral damage problem is the explanation behind the (so-called) fishy behavior of United States.
The problem with IPV (for starters) is that it’s five times more expensive, but set that aside because obviously human life is way more precious. Here’s the sucker punch, IPV is several times weaker inducer of protection as compared to OPV and therefore can’t serve as a reliable source of protection from polio.
This obviously raises the question that if so then why is United States using IPV, is it less concerned about safety of its citizens? No, the IPV is perfectly effective in a Polio free society, but relatively useless in one which already contains polio. So, they can use IPV and they WILL be safe but we can’t because we have polio surrounding, in our sewage system and its levels are so high that IPV isn’t enough to fight it.
On the other hand United States eliminated Polio decades ago, but if somehow their population would encounter a higher level of polio virus then there will be an epidemic.
This is exactly the reason that Pakistanis are soon going to have, a lot of trouble while travelling internationally, unless they have a vaccination certificate.
So how do we solve this? It’s rather easy, make sure that each and every child gets vaccinated next time polio teams come to your neighborhood.
The only way to permanently rid us of this menace is to get over with it once and for always. Once the circulating virus is eliminated then only can Pakistan switch to the safer version of vaccine, and ensure that none of our children face a disability because of polio virus.
If my words can’t convince you, feel free to read a more detailed and technical account of this situation written by Dr Elias Durry, he is the head of the Polio Eradication Initiative at the World Health Organization.
The writer is a final year student at Atta-ur-Rahman School of Applied Biosciences and an executive member of NUST BioReach Society