Professor: Brazilian variant dominant in T&T


Professor: Brazilian variant dominant in T&T

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MORE infectious than its “parent” virus, the Covid-19 P1 (Brazilian variant) is now “pretty certain” to be the dominant strain in Trinidad and Tobago, having expanded rapidly since it was first detected locally in April 2021.

Professor of Molecular Genetics and Virology at The University of the West Indies (The UWI), Christine Carrington, said yesterday although the sampling method being used up to recently for genomic sequencing of the Covid-19 presence could not speak directly to the variant’s dominance, testing since the beginning of May 2021 has suggested that it has taken over.

However, Carrington could not provide data on how many local Covid-19-related fatalities had the variant of concern in common, as the method involves “blind” samples sent to The UWI which do not provide details as to the origin of the swabs.

Speaking at the Ministry of Health’s virtual news conference, Carrington said of 521 samples received for genome sequencing from December 2020, 38 per cent of the total featured the Brazilian variant. But of testing from May 11, Carrington said P1 “accounts for 90 per cent of the sequences”.

Genome sequencing differs from polymerase chain reaction (PCR) testing and is more complicated, she explained.

The method reveals the detailed structure of the virus’s genetic material and “is the only way to detect and fully characterise new variants and to unambiguously tie it to existing ones”, Carrington said.

The UWI conducts these exercises on behalf of the Ministry and Carrington had noted that the variants detected in T&T so far were the United Kingdom (Alpha) variant and P1.

She noted, though, that up to recently not all samples were random and some could have been part of clusters where the variant was present. She said the samples “are not all random so we can’t extrapolate directly from this to the population”.

It was not conclusive, therefore, to say that it was the dominant strain based on this method but “we can be pretty certain that is has expanded and is the dominant strain right now”, Carrington stated.

Thousands of mutations

a common occurrence

Chief Medical Officer (CMO) Dr Roshan Parasram later stated “seemingly P1 has replaced variants of concern as the major strain circulating” in T&T.

Carrington noted that it was “the norm” for thousands of mutations to occur when a virus is introduced and infections spread, with some strains becoming quickly extinct and others emerging to dominate. This was not unexpected and the pattern could be seen in other countries, she said.

Responding to a media question, she confirmed if someone in a cluster was infected with the P1 variant, the entire cluster was also likely to be so infected.

This was why random testing presented a more accurate view of the variant’s widespread presence, though it has been acknowledged that the variant is part of T&T’s community spread.

If The UWI receives ten samples from a cluster and nine of those are P1 positive, it could not be said that 90 per cent of infections in T&T were therefore of the variant as they would have come from the same cluster.

“Since the samples that we sequenced were not all randomly selected, the proportions of the different lineages shown are not necessarily representative of the general population,” Carrington said.

But detection of the P1 variant has increased steadily “week to week” and especially from epidemiological week 14 to 19, she disclosed.

As for any correlation between the P1 variant and increased deaths locally, Carrington said she “can’t answer that”.

Vaccinate against death

Originally detected in Brazil, the variant has been show to be more aggressive in its ability to spread but it is not showing itself as resistant to Covid-19 vaccines currently being used in global inoculation programmes.

This includes T&T, where the Sinopharm and Oxford-AstraZeneca vaccines are in use.

Carrington said these vaccines should prove effective in preventing severe disease and death, adding that infection was not the same as “disease”.

The professor appealed to citizens to get vaccinated and “give themselves a fighting chance.”

Carrington said lowered death and hospitalisation rates were being seen around Brazil among the elderly, where the Sinopharm vaccine was in use.

She had mentioned that Sinovac, China’s second vaccine after Sinopharm to be approved by the World Health Organisation (WHO), offered the same method of inoculation via an inactivated, whole virus.

Carrington addressed public buzz around the case of the Seychelles, where Sinopharm and AstraZeneca were in use but there were reports of increased infections.

But not every person who gets infected also gets sick, she said, and 80 per cent of those hospitalised in the Seychelles were not vaccinated—while there were “zero deaths” among the vaccinated.

Parasram also stated “different endpoints are given by different vaccine manufacturers in terms of their trials”.

However, he said, “The one Sinopharm would have used was the protection from severe disease or death and their rate is 78.1 per cent. So in 78.1 per cent of the people that take Sinopharm you get that full rate of protection.”