by
Katrina Welch
Will you take it? This question has been up for discussion over the past few weeks as thousands of vaccines arrived on island to bring a great fight against COVID-19 in Barbados. While many were prepared to receive their vaccination, fear and apprehension flooded the nation as several people expressed their disinterest in receiving a vaccine at this time.
Much of this trepidation was rooted in a lack of knowledge and understanding about the development of the vaccine, its efficacy and its necessity. Therefore, Better Health magazine took the time to chat with Immunologist and Chair of the UWI COVID-19 Task Force Professor Clive Landis about the Covishield vaccine which is being widely administered in Barbados.
Prof. Landis, who is also the Pro-Vice Chancellor for Undergraduate Studies, answered six of the most frequently asked questions about this vaccine which was developed by Oxford-AstraZeneca.
The Covishield Vaccine, which was developed by Oxford-AstraZeneca is now being widely administered in Barbados. How safe is this vaccine?
The Oxford-AstraZeneca vaccine has gone through the range of clinical safety and efficacy trials. The interim analysis of the phase 3 study was sufficient for it to be granted regulatory approval by the UK Medicines Agency and since then, the European Medicines Agency granted full regulatory approval.
More recently still, the World Health Organisation gave its endorsement and it’s important to state that they also specifically gave approval for the Oxford-AstraZeneca vaccine, called Covishield that is made under license in the Serum Institute of India. This is the vaccine that Barbados has been provided with as a gift from the government and people of India. The Serum Institute of India is the largest vaccine manufacturer in the world, a highly respected biotechnology company that is already accredited with the World Health Organisation, so there can be no question about the safety of the vaccine.
How was this vaccine developed so quickly?
This COVID-19 vaccine is not the first vaccine that the Oxford research team has made against a coronavirus. In recent years, coronaviruses have jumped into the human population from the animal population three times. First, from civet cats in China in 2003 called Severe Acute Respiratory Syndrome (SARS). Then, from camels in 2012 called Middle East Respiratory Syndrome (MERS).
Then in 2019, one we don’t know the animal vector yet, but we think COVID-19 may have crossed from bats to humans. The Oxford team had just completed making their vaccine against MERS from 2012. All they needed in order to adapt that for COVID-19 was the sequence for the spike glycoprotein of this new virus which was published by the Chinese on the January 9, 2020. As soon as the Oxford team had that sequence they were able to go straight into animal studies, because they had an already existing vaccine platform against another coronavirus that had already been fully developed.
Secondly, regulatory approval can be quite a bureaucratic process but because of the urgency of the pandemic, all of the regulatory agencies said they will consider vaccines which have gone through phase 3 clinical trials as soon as the data is available.
So there has been no short cuts whatsoever in either the development or in the approval process for the vaccines. The sheer urgency of the situation and the fact that existing vaccines already had been developed and could be exploited was how the Oxford-AstraZeneca came to be developed so quickly.
There are at least two other well known brands of vaccines which have been developed. Are they all equally safe and efficient?
These vaccine products are not identical and you get some pros and cons for all. So, for example, severe allergic reactions have been witnessed for the Pfizer and Moderna vaccines but no severe anaphylactic reactions have been recorded for the AstraZeneca, so that would appear to have the better safety profile.
In terms of the efficacy, that is how it protects a person from contracting the virus, the Moderna and the Pfizer vaccines have a higher efficacy, around 90 per cent. However, the latest results coming out of Scotland, where they compared the Pfizer vaccine and the AstraZeneca Vaccine on hospitalisations, showed that after one shot there was a 94 per cent reduction in hospitalisations for people who received the AstraZeneca vaccine and an 85 per cent reduction in hospitalisations for persons who received the Pfizer vaccine. So, this is really important to remember that this vaccine that we’re getting in the Caribbean is highly effective at protecting people from severe disease and hospitalisations.
As more than one dose of the Oxford-AstraZeneca vaccine is required, when does its effectiveness begin?
In the Phase 3 study of 35 000 people conducted in the UK, Brazil and South Africa, which was recently published in the Lancer Journal, it was shown that after one dose of the Oxford-AstraZeneca vaccine a person has 76 per cent protection which begins after three weeks. Then, the optimum period for you to receive the second dose is three months.
This is new information on the dosing interval emerged from the most recent analysis and that was also supported by the World Health Organisation which recommends the vaccine against any of the mutant strains. Absolute maximum protection is achieved two weeks after the second dose, but please understand you already have significant protection after the first dose.
Do people who have had COVID-19 and recovered still need to receive the vaccine?
They need to be vaccinated but there is some discussion in scientific communities about whether they should have one dose or both doses of the Covishield vaccine. Currently, the recommendation is that they have both doses, but this will require further scientific study.
Why isn’t the vaccine being administered to minors below the age of 18 at this time?
In the safety and efficacy trials, nobody was included below the age of 18, so we don’t know how it would react and respond. Right now the regulatory agencies are considering applications from all the major vaccine manufactures to go through the same kind of safety studies that were done for adults and to repeat them in children. Only when those studies are complete, and when regulatory approval has been given, can we think about giving them to children.
