Inside Oxford vaccine Covishield's adverse side-effects: What do we know so far

Oxford University-Astrazeneca backed AZD-1222, to be marketed as Covishield in the Indian territory might be one of the strongest candidates we have right now, but it has been embroiled in controversies of late. From a 'silly error' during the trial stage which spiked up efficacy rates incorrectly, to the neurological complications which brought the trial to a halt some months back, there have been one too many lapses over the ambitious COVID-19 vaccine which went into trials months back.

Just a week ago, another vaccine volunteer from Chennai sounded off an alarm by reporting neurological problems post receiving the shot, which reportedly, also left him incapable to work. He has also gone ahead and sought Rs. 5 crore compensation, in a battle which has been grabbing eyeballs.

While the pharma companies in the centre have repeatedly vouched for the vaccine's safety, the lapses and side-effect discovery is one of the reasons why phase III trials are so critical for a vaccine. Many medical experts have also questioned the company's way of handling the trials. We present to you some key takeaways from the Oxford vaccine trials:

Initial investigations revealed that the Oxford vaccine was able to offer upto 70 per cent efficacy, which could further be scaled upto 90 per cent on a full-dose regime. The only problem being-the results were derivative of a small mistake. The 3000 volunteers involved in the trials were wrongly given a miscalculated dose, and hence, subjected to incorrect observations. While the company blamed it on a ‘manufacturing’ fault, the trials bring a lot into question. It remains to be yet another reason why we must not blindly trust the workings of a vaccine.

The changed efficacy reports were witnessed when volunteers who were part of the trial were mistakenly offered a wrong dose than what was initially fixed. The makers made an error in measuring the concentration of vaccine doses which led to a delay.

Scientists overestimated the dosage needed for over 2700 volunteers, which led to them administrating a half-dose in the first phase, which further tweaked results.

Right now, to our benefit, the half-dose error didn't expose participants to adverse effects and complications, however, had it been the other way around, it could have risked the health and safety of thousands of volunteers.

Oxford's mistake also falters against the working of clinical trials- where every detail is scrutinized and done uniformly.

Nonetheless, this is something we do need to realize- vaccine doses administered incorrectly can lead to lags and hazardous health effects.

The Oxford vaccine make has tons of pros and cons, including the recent hiccup. Even so, it still remains one of our best vaccine shots in rooting away novel coronavirus. The vaccine still has a strong efficacy rate of more than 60%, which is good enough for a vaccine roll-out in the current timeline.

We must also remember that the vaccine also scores high on other grounds, including immunogenicity and tolerability response, meaning it can still deliver sufficient, desired results.

Again, identifying possible lapses and faults are bound to happen in large-scale trials. This is yet another reason why vaccines and experimental drugs aren’t rolled out for public use before the end of phase III trials.

Phase III trials help identify possible problems, side-effects and any complications, giving makers enough time to work on the mistakes and measure safety response. While Oxford trials may be subject to secondary investigations now, the recent mistake would allow scientists to deliver a more suitable and ‘safer’ vaccine for billions in need.

Oxford’s vaccine shot remains to be the best vaccine shot for India, and the ones which we might get our hands on at the earliest. However, the recent discovery should be treated as a safety pause and demand correctional steps.

Experts opine that Serum Institute of India, which is responsible for conducting trials in India can conduct additional trial studies and review data to finalize a set dose which can be then used for millions who wish to be inoculated. Immunogenicity and tolerability studies will also provide additional support before the vaccine can be marked ready for use.