Vaccines are the ultimate-they prevent by aiding the production of specific antibodies against the bug. Once vaccinated successfully, the chances of the candidate getting the infection is negligible.
The story of how Edward Jenner observed that milkmaids who had caught cowpox did not catch smallpox, and then his trial of inoculating the vaccinia (cowpox virus) into humans to produce cross antibodies against variola (smallpox virus) changed the world and eradicated the disease. It was the first successfully developed vaccine-the term vaccination coming from the vaccinia virus that it contained.
Since then medical history is studded with discoveries of vaccines against rabies, polio, hepatitis and other infections. Truly, the concept of purposefully injecting a small portion of dead or attenuated organism, large enough to produce an immune response but too small to precipitate the disease, is vaccination. The process of determining the amount of organism, whether to use live bugs or dead protein fragments, how much to use to evoke the response etc, is clinical trials.
Once perfected on the bench, it needs to undergo first animal and then human trials to look for side effects.
The motto of medicine, Do No Harm, is most important in discovery. Its potency to stimulate antibody production and create an impact in the immune memory, so as to call upon this reservoir at any time, even years later, to recruit and rapidly deploy antibody production in crisis, is the true efficacy of vaccination. The trials and tribulations involved in bringing the vaccine from the laboratory to the pharmacy are mind boggling and wrought with frustration and challenges. In medical history, the fastest journey from scratch to finish has been about five years.
But mere vaccine invention is not enough. The capability to deal with mutations-the process by which an organism partially, but discernibly, changes its chemical and physical structure to look like a distant cousin of the same family-to retain its efficacy, the facileness of storage and frequency of administration are factors that contribute to success.
With Covid clouds hanging low, different labs are employing various techniques with the aim of producing lasting immunity against Covid-19 without missing out the mutations of ‘Covid- 20’. Of course, this time there will be the obligatory fast-track factor even though the US elections are over.
Vaccine science has always been perfected from results-the injectable polio vaccine of Salk, though effective, was replaced by the oral one of Sabin. Likewise, even the single shot shingles vaccine, introduced as Zostavax in 2006, is now fading out because of evidence of poor potency and being replaced by the dual dose Shingrix in 2017. Point to note in the shopping list of overseas travellers who want to invest in health.
So, while the ‘Chhalaang’ against Covid with vaccines continues, the best ploy is still your mask and distancing.