Sanjiva Wijesinha -writer and physician

Short stories, Travel and Health Information

A Vaccine for COVID?

Despite US President Donald Trump during the presidential debate today blithely and mendaciously claiming “We will have a vaccine in a few weeks” the truth of the matter is that an effective and safe vaccine will probably not be available until well into 2021.

Vaccination, the effectiveness of which was first proved to the British scientific establishment by English physician Edward Jenner around the end of the 18th century, is achieved by administering a Vaccine into a person’s body – which then ensures that this person develops protection against the disease. A vaccine is prepared from the actual germ responsible for the disease – a bacterium or a virus – that is in a weakened (attenuated) or killed state or even from specific proteins obtained from the germ. The body’s immune system recognises the foreign substance introduced into the body invaccine form (which being attenuated or dead cannot cause any disease) and starts to produce special immune cells (immunocytes) – so that if the actual germ manages to enter the body it is rapidly targeted and destroyed by these immune cells.

Currently there are several laboratories in the world racing to prepare a vaccine against the COVID virus such as Sinopharm in China, Oxford University’s Jenner Institute in England and Johnson & Johnson in the US. All these vaccines are promising – but not only their efficacy but also their safety need to be established in what are called Phase III Trials.

The Oxford Vaccine is being developed in collaboration as a Not for Profit venture with pharmaceutical giant Astra Zeneca. Says Prof Andrew Pollard, Director of the Oxford Vaccine Group  “The Vaccine is made by combining the genetic code of COVID 19’s spike proteins with a harmless attenuated virus that causes the common cold in chimpanzees.”

The resulting antigenic material is injected into healthy volunteers to ascertain if they will become immune to the disease causing COVID irus. Currently the Oxford vaccine is undergoing Phase III trials in over 20,000 volunteers in the UK and other counries.  It is envisaged that a person will need two separate doses (an initial dose plus a booster dose given about a month later) to achieve immunity.

The vaccine trials are being conducted under stringent safety precautions. If an unexpected illness or death occurs in one of the trial volunteers, the trial is paused until the evaluating team assesses the situation to make sure the adverse event could not have been due to the vaccine. It is only after such an evaluation finds that the vaccine was NOT the cause of the adverse event that the trial is allowed to resume. Such pauses are actually a good thing – because they emphasise the stringent safety precautions that are followed.

We still do not know for how long the immunity conferred by these COVID vaccines will last. Will the virus mutate and change, as the Influenza virus does? If that is the case we will have to keep abreast of such mutations and (just as in the case of Influenza) produce a new strain of vaccine every year to protect us against the mutated COVID virus.

When a vaccine becomes available and is proven to be safe and effective, it is important that everybody gets vaccinated because that is the best way of ensuring ‘Herd Immunity’ and protecting the population against this deadly virus.


2 comments on “A Vaccine for COVID?

  1. susanawee
    October 23, 2020

    Thankyou Sanjiva for such comprehensive information


  2. Tilak Mendis
    October 25, 2020

    Good work, Sanjiva! It might be worth adding that new drugs have a high failure rate in phase lll clinical trials. This is not specific for this vaccine. However Hwang et al. assessed 640 phase 3 trials with novel therapeutics and found that 54% failed in clinical development, with 57% of those failing due to inadequate efficacy. So I agree that a vaccine in this case is certainly not imminent.


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This entry was posted on October 23, 2020 by in Health Matters and tagged , , , .

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