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A study on the genetic diversity of the SARS-CoV-2 coronavirus detected three new variants of the virus that circulate in the second wave of the covid-19 pandemic in Portugal, a researcher from the Ricardo Jorge National Health Institute (INSA) advanced this Wednesday.
One of the three variants represents around 70% of the viral genomes analyzed in the study and is characterized by “a very specific mutation” that affects the regions where antibodies bind.
“Now we have verified in this study that we did it in collaboration with the Gulbenkian Institute of Sciences [IGC] that the variants that are characterizing this second wave in Portugal have mutations that were not described during the first wave ”, said João Paulo Gomes, head of the bioinformatics unit of the Department of Infectious Diseases at INSA.
The three most frequent variants, each recognized by a different change in the Spike protein (A222V, S477N or S98F), were detected in all regions of mainland Portugal, suggesting that they were the main co-responsible for the second epidemic wave of SARS -CoV. -two.
The coordinator of the “Study of the genetic diversity of the new coronavirus SARS-CoV-2 (COVID-19) in Portugal” explained that this situation is the result of “a process of adaptation of the virus to humans.”
Regarding the mutations observed in the country, the researcher stated that some “are very interesting”, but not exclusive to Portugal, highlighting that “one of the mutations characterizes a variant that appeared in Spain a few months ago and that spread throughout the rest of Europe at an astonishing speed “and that was now observed in Portugal in 70% of the samples analyzed in the study
Asked if this variant is more lethal and if it can explain the increase in cases in the second wave, the researcher said that “in clinical terms there is no evidence that there is greater severity in terms of the disease.”
The increase in cases may be justified by the existence of genetic variants with a greater transmission capacity, but the researcher considers that social behavior is the basis for the largest number of cases in the second wave worldwide.
“During the first wave we observed more severe restriction measures that allowed more control, now we are not observing that because at the end of the first wave there was a general deflation and we never went back to a real confinement” because “it would be very difficult to do so.” economic, social, family reasons
According to the study report, released today, 2,234 sequences of the SARS-CoV-2 genome, which causes COVID-19, obtained from samples collected in 68 laboratories, hospitals, institutions, representing 199 municipalities in Portugal.
In this update of the study, 449 more sequences of the SARS-CoV-2 genome were inserted, collected since the beginning of November in 19 collaborating laboratories / hospitals throughout the country, representing 16 districts of the continent and the Azores, in a total of 113 municipalities. .
Of the total number of sequenced viruses, no virus was found with the combination of mutations exhibited by the variant currently circulating in the UK or the variants associated with outbreaks of SARS-CoV-2 in mink farms in Denmark.
“Interestingly, the genetic variant that marked the first wave of the covid-19 epidemic in Portugal (with the mutation in Spike D839Y) was not detected in the genomes analyzed for the second wave. This suggests that the public health measures implemented will have mitigated the continuation of transmission “, emphasizes the document.
The covid-19 pandemic has already claimed nearly 1.7 million deaths worldwide since December last year. including 6,343 in Portugal.
