KARACHI: A webinar bringing together a panel of experts on Saturday, shed light on the myths, misconceptions and effectiveness of vaccines against mutations of the coronavirus. Titled ‘SARS CoV 2-VOC (UK variant) 202012/01: will vaccines still work?’, the webinar also looked at the emerging data, which shows that the UK variant is 56 per cent more transmissible than previous variants.
Providing an overview of the virus structure, the UK mutations and genotype in Pakistan, Prof Zahra Hassan, section head of Molecular Pathology, Department of Pathology and Laboratory Medicine, Aga Khan University, said that all viruses have an envelope that encases the virus’s nucleic acid. “This envelope is made of E protein, Membrane protein, Spike protein, and this word ‘spike’ has become very important in the context of SARS CoV because the SARS CoV spike protein is thought to help it bind to the cell that it enters. And the concerns about generating changes at the level of the genome can be related to any of these proteins. So in terms of perspective of the virus, there are both structural and nonstructural proteins. The structural proteins that the envelope is made of is where changes can occur.
Experts shed light on myths, efficacy of vaccines against mutations of coronavirus
“So the first important change that people noticed in the spike protein was related to a change in a mutation which was at the 614 residue. That was observed very soon after SARS CoV was identified. Essentially, there is a whole field of pathogen epidemiology or genomic epidemiology that is related to trying to understand how the virus changes,” she explained.
“From January 2020 till now, we have got a lot of information about genomes of SARS CoV strains that have been identified across the globe and it’s the first time that so much data has been shared. There are tens of thousands of sequences available globally. The virus does change as all viruses do and essentially these virus changes have been linked to the development of different lineages of families across the globe and the main families are the A and B and the diversification of the B lineages have been found to be the most common,” she said.
“What we have seen in Pakistan. At the Aga Khan University, we have had the opportunity to look at some virus strains from the beginning of the pandemic in March. And, of course, we had had a look at a subset of strains. The predominant strains globally are related to the G lineage. And in Pakistan, too, we have mostly seen the G lineage and the GH lineage. But what came out of Wuhan was the S lineage which split from S to L and which went from L to V to G.
“In terms of diagnostics, does the variety in the lineages make a difference? No, because the diagnostics for SARS CoV have been designed to be fairly robust. And tests based on identification of genetic changes are for more than one gene,” she said.
“We have mapped a number of stains to get a perspective of relatedness in terms of global strains. We have found a variety of countries that are matching with such as in the West, the UAE, Iran, Iraq, etc. And it is not surprising because these are coming from people who have been travelling, while some strains are local strains. So as expected, there is a lot of commonality within the strains and we will learn more as we go along and are able to get more data on Pakistani strains,” she said.
“The new variant and its impact, well, about 23 mutations have been identified to occur in this variant. One has a change in the spike protein, the envelope mentioned earlier, which is what probably leads to increased transmission. From a genomics perspective, the variations in strains occur in different regions too. So you need to think about what immunity means to the host, bacterial, fungal and viral pathogens are dealt with by different cells, including first line defender cells. There are also adaptive slow responses. Specific responses generated by exposure to the virus or by immunity developed through a vaccine should be driven by cell responses, and all will develop antibodies,” she said.
The variety in diversity of the SARS CoV virus occurs in different components of the genome. And because the immune responses are also to the different components of it, therefore having some changes on only one part of the protein like the spike protein may change the biology of the virus to perhaps make it more tramissable but it should not take away from the fact that the human host should be able to have an immune response against the virus,” she concluded.
Dr Adeel Ajwad Butt, professor of medicine and professor of population health sciences at Weill Cornell Medical College, Qatar, spoke about the different vaccines available and how vaccines can help build immunity. He also said that natural immunity isn’t enough and getting vaccinated is important “because antibody levels in the body are not universal. Vaccination provides a high level of antibodies. Also there is little or no chance of getting Covid-19 from the vaccine because there is no dead or alive virus in the vaccine,” he explained.
He also said that based on early data, it can be said that the vaccine protects one for four to six months and possibly even up to a year.
Dr Syed Faisal Mahmood, associate professor, Section of Infectious Diseases, Department of Medicine, Aga Khan University, discussed the impact of the mutations to the types of vaccines. His key message was that the vaccines are generally expected to work because they are equipped to recognise the virus effectively.
Dr Mehreen Arshad, attending physician, infectious disease, and assistant professor of paediatrics at Northwestern University School of Medicine, US, elaborated on the mutations and discussed studies indicating that children may now be hotspots and discussed studies indicating that children may now be hotspots. “It is true that children from ages 10 to 19 are at a higher risk and more likely to transmit the virus because even if you close the education institutions, there are still in the malls and cinemas that are open,” she said.
Dr Daisy Ilagan-Tagarda, infectious diseases specialist, chair of the Infection Prevention Control Committee at Diliman Doctors Hospital, the Philippines, shared her experience and how their government in the Philippines is taking steps for it.
Finally, summing up the discussion, the moderator Dr Wajiha Javed, head of Public Health and Research at Getz Pharma Pvt Ltd, said that: “We cannot rely on herd immunity as the level required to reach herd immunity is too high for any population to achieve it without vaccinations. Vaccines do take into account different mutations of the Covid-19 virus and hence are still effective against it. Vaccines are necessary as they help build antibodies in the body.
“Social distancing measures still need to be continued even after one is vaccinated as it takes time for vaccines to work and antibodies to be developed hence it is advised that all those vaccinated continue the social distancing measures and wearing masks even after the doses are administered.”
Published in Dawn, Jannuary 4th, 2021