COVID 19 Vaccine - The reality Check
By Sourab Paul, Karimganj College( Dept of botany)
Almost 5 months into the pandemic. All hopes of extinguishing COVID 19 are dependent on a still hypothetical vaccine. We might have to stay home until we have a vaccine; Schools, colleges, offices were closed and the normal life is now a past.
During many months of misery, August 2020 has given us a small glimpse of hope.
Normal life on the other side and we just have to wait until we have a vaccine.
But amidst all these there are many new questions like how far a vaccine is safe?
Why the vaccine may fail and many other curiosity may arise..
WHY A VACCINE MAY FAIL?
England's deputy chief medical officer Jonathan Van-Tom once said "we can't be sure we will get a vaccine". He was right because vaccines are simple in principle and complex in practice.
An ideal vaccine is the one that protects against, prevent its spread and does the work so safely. But some of these is easily achieved as vaccine timelines show.
More than after 30 years scientist isolated HIV, we have no vaccine yet for it.
The dengue fever was identified in 1943 but the vaccine was approved only in 2015.
The fastest ever developed vaccine was for mumps and even it took 4 years to do so.
The one positive aspect for corona virus vaccine is that the scientists had worked for corona virus vaccine before.
Two corona viruses have caused lethal outbreak before, namely SARS and MERS. Vaccine research went ahead for both of them but none were licensed.
The lesson from these two will help scientist to make vaccine for SARS-CoV-2 but still there are more to know about the virus.
A chief concern is that Corona virus doesn’t tend to trigger long lasting immunity. Researchers at Oxford University analyzed blood from recovered covid 19 patient and found that the level IgG antibodies rose steeply in the first month of the infection and then began to fall again.
The genetic stability of the virus matters too.
The rapid evolution of HIV is a major reason that we have no vaccine for the disease till date. So far the Sars-CoV-2 seems fairly stable but it’s doing mutations. Some genetic changes have been reported in the virus's protein (Spikes) which are the basis of most vaccines. If the spike protein mutates too much then the vaccine will effectively be out of date and might not bind the virus effectively enough to prevent infection.
ANOTHER CHALLENGE IS MAKING ANY VACCINE SAFE?
In the rush to develop a vaccine safety must remain a priority as apart from severely ill patients, the vaccine will have to be checked very carefully for signs of some dangerous side effects.
During the search for a sars vaccine, in 2004 scientist found that one candidate offered from hepatitis.
Another important concern is antibody induced enhancement where antibodies produce by a vaccine actually make the infection worse.
John McCarty, Director of worldwide influenza centre at the Francis Creek institute said " it takes time to understand the particular changes each vaccine throws up and we haven't got any experience in handling this or its components."
Another question is the effectiveness of the vaccine:
The PM of the United Kingdom, Boris Johnson told that a vaccine by no means guaranteed, his chief scientific adviser agreed and added " i would surprise if we didn't end up with something."
In all likelihood, the corona virus vaccine will not be 100% effective. Ideally a vaccine will generate persistent high level of antibodies to wipe out the virus and also the T cells to destroy infected cells.
But each vaccine is different and today no one knows what kind of immune response is good enough.
David L. Heymann who led the response of world health organization to the Sars epidemic said "we don't know if a vaccine can produce an immune response which would protect against future infection."
Vaccines that are certain weakened strains of viruses can be dangerous for older people but may be given to younger people with more robust immune system to reduce spread. Meanwhile older people may get vaccines that simply prevent infection processing to life threaten pneumonia.
The most common question among the all is whether the virus is here to stay or not.
The simple answer to the question is probably yes. Hopes for eliminating the virus starts with vaccine but do not end there.
If we are to choose a vaccine that gives only one year of protection then it is destined to have covid become an endemic.
The virus will also be tough to conquer with a vaccine that beats for years. Unless we have a vaccine available in extreme quantity, that could be distributed quickly in the all communities of the world.
Perhaps we will have to live and adapt with the virus just we are with malaria.
People have to play their part of maintaining social distancing, avoiding casual gathering, washing hands time to time, wearing mask etc.
The proverb "prevention is better than cure greatly holds in the case of COVID 19.
Google (mainly) Immunology, medical researchers