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AstraZeneca and Pfizer promise to deliver vaccines to combat “nastier” variants
By autumn, starting around September or even earlier, AstraZeneca and Pfizer have both promised to deliver vaccines, building on the ones available now, to combat the “nastier” variants (strains) of the COVID-19 virus firstly detected in Brazil and South Africa.
Prof. Neelika Malavige
This was the “good news” that the Head of the Department of Immunology and Molecular Medicine, University of Sri Jayewardenepura, Prof. Neelika Malavige gave before getting into detail about genetic sequencing that her laboratory conducts to keep tabs whether “any untoward things are happening” due to new variants circulating in Sri Lanka.
This is the only laboratory performing genetic sequencing in the country and is funded by the World Health Organization (WHO) under whose guidance countries are carrying out this important work.
Pointing out that the AstraZeneca, Moderna and Pfizer vaccines work against the United Kingdom (UK) variant (B.1.1.7) first detected there and now also found in around 82 countries, she says that there are no datato indicate that the other vaccines work against it, but possibly they too may be effective.
The efficacy of the AstraZeneca and Pfizer vaccines against the Brazilian (P.1 or known as VOC202101/02 in the UK) and South African (501Y.V2)variants – which seem to be similar and also nastier – is lower, she says.
Prof. Malavige explains that AstraZeneca and Pfizer are already“updating” their current vaccines, which are on an easily modifiable platform, to meet these two variants. The AstraZeneca vaccine is a viral vector (adenovirus vector) from a chimpanzee and the Pfizer vaccine is from an mRNA base.
Going into her favourite subject of genetic sequencing, she says that just because people test positive through RT-PCR tests, such a test does not indicate the variant has got into their systems. The variant can only be determined through genetic sequencing. Sequencing is expensive and cumbersome and the WHOshows the way to all countries when to sequence variants, which location to sequence variants from (where there is unexplained activity of the virus) and from what segment of people samples should be taken for sequencing.
“There are many variants, with new variants emerging everyday in this coronavirus which is an RNA virus. It is natural for the virus to mutate while replicating because that is how it evolves. For the virus too, the survival of the fittest rule applies and that is why the UK variant has 30-70% transmissibility than other variants. So this is the variant which will be circulating for a while in many countries,” she said.
Prof. Malavige says that in an area where there is high prevalence of COVID-19, populations gradually become immune to the virus and the virus cannot spread. To escape this immunity and keep spreading the disease, new variants are formed.The UK variant, called this because it was identified there through sequencing, is in India, Bangladesh, Maldives, Singapore and South Korea.This variant caused a lot of trouble in the UK but Asian countries have managed to contain it.
“It was recently found in the community in New Zealand despite that country being dubbed the bestin COVID-19 control, where they have halted tourism, imposed strict border controls and also quarantining. New Zealand is still trying to find out where it started. Just because you find the new variant in the community, you can’t say that control measures of COVID-19 have failed,” she said.
| Sri Lanka’s sequencing numbers “good”Sixteen of 92 samples sequenced by Prof. Neelika Malavige’s laboratory last week, were of the UK variant, with 13 being samples from quarantine centres and 3 from the community. The Epidemiology Unit sends samples from different locations, taking into consideration the WHO guidelines. | |