THE COVID VACCINE

BY Dr. Sanjiva Wijesinha

Despite outgoing President Donald Trump falsely and repeatedly claiming that “we will have a vaccine very soon, very soon,” the truth is that an effective and safe vaccine will not be available until well into 2021.

The effectiveness of vaccination was proved by English physician Edward Jenner around the end of the 18th century. By administering a vaccine into a person’s body, one can ensure that the recipient becomes protected against the disease.

A vaccine is prepared from the actual germ responsible for the disease (a bacterium or virus) that is in an attenuated (weakened) or exterminated (dead) state, or even from specific proteins obtained from the germ.

The immune system recognises the foreign substance introduced into the body in vaccine form (being weakened or dead, it can’t cause any disease) and starts to produce special immune cells called immunocytes.

So if the actual germ manages to enter the body, it is rapidly targeted and destroyed by these immunocytes.

At the time of writing, there are several laboratories across the world racing to prepare a vaccine against the COVID-19 virus. All these vaccines
are promising. However, not only their efficacy but also their safety needs to be established through what’s known as Phase III trials.

The Oxford vaccine is being developed in collaboration with pharmaceutical giant AstraZeneca as a not-for-profit venture. Director of the Oxford Vaccine Group Prof. Andrew Pollard says: “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 pathogen causing COVID-19. The Oxford vaccine is undergoing Phase III trials in over 20,000 volunteers in the UK and other countries. It’s envisaged that a person will need two separate doses (an initial dose plus a booster dose given about a month later) to achieve immunity.

Vaccine trials are being conducted under stringent safety precautions. If an unexpected illness or death occurs in one of the volunteers, the trial is halted until the evaluating team assesses the situation to make sure the adverse event wasn’t due to the vaccine.

It is only after such an evaluation finds that the vaccine wasn’t the cause of the adverse event will the trial be permitted to resume.

Such pauses are prudent because they emphasise the stringent safety precautions that are followed.

We still don’t know for how long the immunity conferred by these COVID-19 vaccines will last.

Will the virus mutate and change like the influenza virus? If that is the case, we will have to keep abreast of such mutations and (as in the case of influenza) produce a new strain of vaccine every year to protect us against the mutated coronavirus.

When a vaccine is proven to be safe and effective, it’s important that as many people as possible are vaccinated because that is the best way to ensure herd immunity and protect our population against this deadly virus.