Now a days, it may not be uncommon in many households to hear the following conversation:
“How long do I have to lock myself inside the house; when can I venture out, without a mask?
Till such time, you get a vaccine shot! “
Yes, Vaccines have prevented many millions of illnesses and save numerous lives every year and for covid too this is purportedly the panacea! Since time immemorial, Conventional vaccine approaches, such as live attenuated and inactivated pathogens and subunit vaccines, provide durable protection against a variety of dangerous diseases. Despite this success, there remain major hurdles to vaccine development against a variety of infectious pathogens, especially those that are able to evade the adaptive immune response. Another type is vectored vaccines that are easy and relatively cheap to make. These adenovirus vector type vaccines can be grown up in cells and used for various vaccines. Once you make a viral vector, it is the same for all vaccines; It is just the genetic information in it that is different. Some of the success stories of prevention of dreaded infectious diseases with these vaccines are, hepatitis B, DPT, MMR etc., Moreover, for most emerging virus vaccines, the main obstacle is not the effectiveness of conventional approaches but the need for more rapid development and large-scale deployment.
The latest version is the messenger RNA or mRNA type vaccines that have the potential for rapid, inexpensive and scalable manufacturing, mainly owing to the high yields of in transcription reactions. They are claimed to be not only safe but are efficient invitro producing specific antigen responses. These mRNA is the ribonucleic acid that transfers the genetic code of the DNA of the cell nucleus to a ribosome in the cytoplasm, that is, the one that determines the order in which the amino acids of a protein bind and act as a mold or pattern for the synthesis of that protein. While adenoviral vectors have been tested in far more people than mRNA vaccines, this new technology is used in only one commercial vaccine today: rabies vaccine to immunise wild animals. So far, no mRNA vaccines have been demonstrated to prevent disease in humans.
What could be some perceived apprehension with the new mRNA vaccine? It is ‘genetically engineered‘ and hence consequences if any, can no longer be cured, just as a person with a genetic defect like Down syndrome, Klinefelter syndrome, Turner syndrome, genetic cardiac arrest, hemophilia, cystic fibrosis, Rett syndrome, etc. This means, the damage caused by the vaccination will be irreversible. Some may even prefer to call these “promising vaccines” a crime against humanity! It is entirely another matter that some section still believe other types of vaccines also might be similarly harmful!
In the quest to find a vaccine answer for the covid, all the three approaches were pursued by the researchers, the attenuated, adeno-vector based and mRNA types. The first to reach the goal post are the new mRNA types! And the whole world is ecstatic! Isn’t it ironic? A genetically modified vaccine formulation, m-RNA types, hitherto not tried at all, has been declared safe by scientists in just less than six months of its ‘invention’. Public accept what these scientists say. But not when they say, genetically modified food like brinjal, cotton etc., as safe – even after decades of rigorous testing through the same technology! Why different yardsticks? Stranger than fiction? Yes, If it comes to saving ones own life when drowning, even a ‘thin straw’ is good enough! Now a third vaccine, an adeno vector based report success. And all the three vaccines would begin the battle the dreaded ‘monster’ before this December end of this year in the market.
It is indeed a reality that the beginning of the end of the pandemic is at last visible in the gloomy tunnel. The world has witnessed a disaster ever since the Second World War. Vaccines seem to be only last straw. Pessimists, a few months back declared: no vaccine in the near future and the human life cost would be very high to reach the herd immunity etc., But there were a few optimists around who were now only proved right.
The two mRNA type vaccines report stunningly high efficacy of over 90% and the other vaccine based on adeno vector based report just over 70%! While the claims of the two mRNA vaccines did not raise many eyebrows, the time tested adeno virus type vaccine from Oxford reasearchers, did. In trying to match the competitors claim, this has set off discussions on human immune system; The puzzle is the initial results of phase-3 trials, that has many scratching EK054757589INtheir heads: a lower dose producing better result 90% while higher dose, a lesser efficacy of 62%. Hitherto such findings are not reported.
Would the dose-response inversion be a sign for concern? May not be! One possible explanation is that the lower initial dose does a better job of getting through the body’s defenses, allowing the vaccine to infect cells and create the immune response. Another theoretical reason is more complex: The immune system may become inured by the initial high dose of vaccine and then ignore the subsequent dose, a phenomenon known as tolerance or immune desensitization. Either one would have the potential to blunt the effects of the shot. The researcher suspects a possibility of lower antigen levels triggering the immune system better. He also explains that the finding as ‘serendipity’ when they analysed the subject volunteers reported lower than expected side effects such as, arm aches, fatigues, head aches etc., when the initial dose regimen was a full first dose. When they halved, the responses were as predicted! How many would buy this is left to one’s imagination!!
A plausible conclusion could be that today’s science has not fully understood the human immune system. This is the ‘naked‘ truth and this explains why one does not get provoke the expected immune response with everyone. But the bottom line is, even the two full-dose regime’s lower efficacy number of 70%, crosses the World Health Organization’s benchmark of 50%, though ‘headline’ number of 90% might also ultimately prove to be right. Any of the respiratory disease vaccines available in the market every year are around only 60%!
The U.K.’s Medicines and Healthcare Products Regulatory Agency has already started its analysis based on data it’s received in a rolling review. Indian regulators may also soon approve following the footsteps of their colonial bosses!
Would any vaccine be absolutely harmless? No one can vouch for such safety! In such a scenario, would you choose the time tested attenuated or adeno vector type vaccine with just over 60% effectiveness or the yet unproven mRNA type vaccine with over 95%?
On the other hand, If you are totally sceptical of vaccines, you can wait for the feedback’s of vaccination of millions of population worldwide to choose the best one or be prepared to be inside your locked paradise a little longer till everyone else is vaccinated and the virus disappears from the planet! Though after getting the shots, you can move around and socialise but may be advised to follow the present covid protocols for some more months.
Should vaccination shall be made compulsory? When you consider the free movement of an infected individual or even a benign without a mask, as a criminal offence endangering the public at large, why not the same yardstick to a ‘potential’ infector? But nowhere in the world such a law exists making it compulsory!
A recent survey conducted In 19 countries shows, current levels of willingness to accept a COVID-19 vaccine are insufficient to meet the requirements for community immunity! Many are apprehensive about their government ‘cutting corners’ that could compromise their personal safety!
Steven Wilson, a professor at Brandeis University and co-author of a study entitled “Social Media and Vaccine Hesitancy” published in the British Medical Journal last month, saw a link between online disinformation campaigns and a decline in vaccination. “My fear regarding the impact of disinformation on social media in the context of Covid-19 is that it will increase the number of individuals who are hesitant about getting a vaccine, even if their fears have no scientific basis,” he said.
This has also been complicated by the ongoing controversy in US: A group of former US Food and Drug Adminstration commissioners and several companies developing COVID-19 vaccines and biomedical advisory bodies have urged the US federal government to base any pending vaccine approvals on clinical data and not bend to political pressure from the incumbent US president to approve a vaccine before the US elections.
With more than one vaccine flooding the market, the air is full of optimism as well as unfounded fears. But in the history of vaccines there is a solid medical and scientific evidence that the benefits of vaccines far outweigh the risks. There are two major controversial vaccine programs that are cited as examples against vaccines and importantly both are complications in children – MMR vaccine and anti dengue vaccine:
The connection between vaccines and autism originated in a 1998 paper published in The Lancet that concluded that eight of the 12 patients (ages 3–10) developed behavioral symptoms consistent with autism following the MMR vaccine (an immunization against measles, mumps, and rubella). The Lancet officially retracted the article stating that several elements of the article were incorrect, including falsified data and protocols. This Lancet article has sparked a much greater anti-vaccination movement, particularly in the United States. Even though the article was fraudulent and was retracted, 1 in 4 parents in US still believe vaccines can cause autism.
In an anti dengue vaccination program, Philippines vaccinated schoolchildren with Sanofi Pasteur‘s Dengvaxia vaccine. The program was stopped when Sanofi Pasteur advised the government that the vaccine could put previously uninfected people at a somewhat higher risk of a severe case of dengue fever. In late November 2017, the program was suspended: As of August 2019, over 600 people (mostly children) that had received at least a single dose of the vaccine had died, though not necessarily caused by the vaccine itself. It was later clarified that as there are four types of dengue, such complications could scientifically be explained. If antibodies for any of the four is not developed, and if dengue infection of that type unfortunately occurs, there is severity of complication compared to the one not having any antibodies or not vaccinated at all. This hyper sensitivity to the one is noticed in regularly infected cases. A political controversy that erupted over whether the program was run with sufficient care and who should be held responsible for the alleged harm to the vaccinated children, killed the whole vaccination program lock stock and barrel.
There are many viral infections for which there is no viable vaccine, for example AIDS. But should all these deter a covid fight?
It is very important that dissemination of proper information is very vital to allay fears that the present vaccines are rushed without proper safety assessment. Scientific World has accumulated adequate experience to understand how safety could be reasonably guaranteed. Unwavering fight against the covid virus only could make the world stand up.
Compliance to vaccination largely would depend on the faith of public on their government! Any vaccine is only as effective as our capacity to deploy it to a population, as no vaccine is 100% effective! The herd immunity depends the fraction that actually develops the antibodies, that would depend on the fraction vaccinated and the efficacy, with a 60% efficacy vaccine, more than 90% have to be vaccinated to get even 54% to develop immunity, which might just meet the bench mark requirement of only 50%!
So, on one hand there is a growing apprehension on vaccine safety, epidemiologists are certain that large scale vaccination is the only way to overcome the pandemic permanently.
Credits:
3. https://www.historyofvaccines.org/content/articles/different-types-vaccines
4. https://www.healthline.com/health-news/kennedy-q-a-about-vaccine-safety
5. https://www.nature.com/articles/s41591-020-1124-9
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