ChAdOx1 nCov-19: A stinging pain to bear for a widespread future relief

Being in deepest of terror, agony and vulnerability, humanity has been confronting ‘COVID-19’ like those soldiers in the battle-filed left with shield in hands only, without sword to counter-strike with. The defense is continued, tooth and nail, with existing treatment regime and medical equipment at disposal and simultaneous foraging for the rapier.

Few drugs were recommended by WHO in their SOLIDARITY trials in recent past to handle the critical situation. However, development of vaccine as a prophylactic measure is considered the most effective strategy, by the experts, to overcome the pandemic. Currently, about 80 different groups are working, globally, on different strategies (RNA-based, DNA-based, recombinant protein-based, viral vector-based, live attenuated and inactivated vaccines) to derive a suitable candidate. Of them, ChAdOx1 nCoV-19 found itself in limelight for last few days on its beginning of phase I human trial. To note, it’s been frequently (and incompletely) named as ‘ChAdOx1’ on different platforms (as inappropriate as calling it, only, a ‘Khan’-movie, without mentioning Amir, Shahrukh, Salman, Irfan…..). ‘ChAdOx1 nCoV-19’ is the newest member to carry the ‘Chimpanzee Adenovirus Oxford- ChAdOx’ legacy started about a decade ago. A non-replicative form of Chimpanzee-derived recombinant adenovirus vector has been used to express representative proteins for diseases like Influenza, Rabies, Tuberculosis, Zika, Chikungunya etc. to induce humoral immune response in human body. The Spike protein (S), the one probes the viral entry into host cell, is chosen for nCoV-19-specific vaccine designing. Prof. Sarah Gilbert of Jenner Institute, University of Oxford, being the lead of ‘ChAdOx’ tactic development, revealed high confidence on this approach. The first human trial (phase I) was conducted on 23/04/20 by injecting two individual volunteer scientists. The trial would include more than 800 individuals, randomly divided 50:50 to vaccinate a group with nCov-19-protectant while the other with one to protect against Meningitis (a non-COVID control). None of the recipients would know the type he/she got pricked with, but the vaccinator will (single blind randomized assay). So, technically speaking, it would be cerebral glorifying the voluntary of both Dr. Elisa Granato and Dr. Edward O’Neill or none (instead of spreading emotional notes with picture of Dr. Elisa only portraying as a ‘COVID martyr’ in social media, as I observed some. Please believe me, there’s no ‘male chauvinism’, but rather reasonable scientific explanations only, stand behind what I wrote above!!).

On a serious note, scientists are indeed counting on the success of this vaccine, owed to certain advantages (faster application, single-shot use, shorter time span for safety assay) over other approaches. Eventually, University of Oxford has already initiated a mass-scale production (1 million doses to stockpile by September) for this vaccine in collaboration with 7 different organizations around the world (3 in UK, 2 in continental Europe and 1 each in India and China), as narrated by Prof. Adrian Hill, Director, Jenner Institute. The previous members of the ‘ChAdOx’ family performed well in about 12 different disease trials (including one on MERS). However, uncertainty still remains large regarding effectiveness of the present one. More so, the sensitivity and specificity of the aspirant are yet to be evaluated. Albeit, they consider this ‘playing at high stake’ worthy.

The success of the trial largely depends on the dilemmatic factor of exposure of a comprehensive number of vaccinated volunteers to the virus in their natural niche (i.e. with risk of elevated transmission). Prof. Andrew Pollard, Director, Oxford Vaccine Group, University of Oxford, explained it as: “catching the wave of pandemic” for apt assessment of the vaccine to “chase the end”. For us, let’s keep our fingers crossed for success of these endeavors, not being over-expecting under desperation.

Dr. Nirmalya Dey

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