Workers wearing protective suits walk past the graves of Covid-19 victims at the Nossa Senhora Aparecida cemetery, in Manaus, Brazil.(AFP)
Workers wearing protective suits walk past the graves of Covid-19 victims at the Nossa Senhora Aparecida cemetery, in Manaus, Brazil.(AFP)

Coronavirus variant first found in Brazil infected many already recovered from Covid-19: Study

  • The researchers estimated that the variant evades 25-61 per cent of protective immunity arising from infection with previously circulating variants.
By hindustantimes.com | Edited by Kunal Gaurav, New Delhi
PUBLISHED ON MAR 02, 2021 10:10 PM IST

A coronavirus variant of concern (VOC) first detected in Brazil may be up to 2.2 times more transmissible and cause re-infection in people already recovered from Covid-19, a new modelling study has suggested. Researchers at the University of São Paulo, in collaboration with Imperial College London and the University of Oxford, found that a second wave of infection in Manaus, a city thought to have a high level of existing immunity from the first wave, was associated with the emergence of the new P.1 variant.

“P.1 accrued 17 mutations, including 3 virologically-important mutations in a region of the spike protein that interacts with the receptor the virus uses to enter human cells," Dr Nuno Faria of Imperial College London said in a statement.

Using statistical analysis of genome sequencing data, the researchers found that the P.1 lineage, which has been identified in more than 20 countries worldwide, has likely been circulating in Manaus since early November 2020. The study has not yet been peer-reviewed or published in a medical journal and available as a preprint.

They have estimated that the variant evades 25-61 per cent of protective immunity arising from infection with previously circulating variants. This means 25 to 61 out of 100 people previously infected with non-VOCs that circulated in Manaus could be re-infected if they are exposed to P.1. The study further estimated that the variant is associated with a 1.1-1.8 times increased risk of mortality compared to previous variants circulating in the Amazonian region.

Read | Covid-19: Which countries have most number of fully vaccinated people?

However, the researchers acknowledged the limitation of the study, saying it is unclear whether the increased risk of mortality is due to the variant or the collapse of the health system in Manaus due to the large second wave. The modelling study has only considered acquired immunity from the previous infection and not from vaccination, which means there’s no evidence that current vaccines are less effective against P.1 lineage.

The team stressed that enhanced genomic surveillance of variants around the globe remains critical to accelerating pandemic responsiveness. "Global collaborative efforts on rapid virus genome sequencing are allowing us to identify SARS-CoV-2 lineages of concerns in near real-time. Yet, uncertainty in the ways SARS-CoV-2 is changing and implications for vaccine design calls for much more sequencing and analysis of virus genomes globally,” Professor Ester Sabino of Universidade de São Paulo said in a statement.

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