A mutated strain of the SAR-CoV-2, the virus responsible for the coronavirus pandemic worldwide, has been found in the Philippines.
According to the Philippine Genome Center, the D614 variant was found among nine COVID-19 positive samples in Quezon City in July while in the month prior, both the D614 and the G614 have been detected in a small sample of positive cases.
“Although this information confirms the presence of G614 in the Philippines, we note that all the samples tested were from Quezon City and may not represent the mutational landscape for the whole country,” the Philippine Genome Center clarified.
In its report, the Philippine Genome Center suggests that based on data from an in vitro study, “viruses with the D614G mutation appear to have higher levels of viral RNA and higher titers of pseudo viruses.”
It also stated that while G614 is now the dominant viral state, the said mutation can increase the viral rate of transmission.
“However, there is still no definitive evidence showing that carriers of the G614 variant are actually more transmissible than those with D614 and the mutation does not appear to substantially affect clinical outcomes as well,” it added.
The Coronavirus Disease 2019 (COVID-19) is caused by SARS-CoV-2 virus, the genome of which is a single-stranded positive sense RNA that is about 30,000 bases long containing 11 genes with several regions known to be immunogenic, including different parts of the Spike (S) protein, the Nucleocapsid (N) protein, as well as the Membrane (M) and Envelope (E) proteins.
“Coronaviruses including the SARS-CoV-2 are characterized by the presence of spikes surrounding the virus core,” the Philippine Genome Center explained. “These spikes enable the virus to attach to human cells through the ACE2 receptor. Since the spike protein mediates the entry of the coronavirus into host cells, insights into mutations affecting this region is important to understand its infectivity as well as its antigenicity.”
Records from Global Initiative on Sharing All Influenza Data (GISAID) show that among the most frequently observed amino acid replacements from high quality genomes deposited in its database, the D614G mutation at the spike protein is the most common.
“In the D614G variant of the virus, the ‘D’ amino acid aspartate at position 614 of the spike protein has mutated to the ‘G’ amino acid glycine. The G614 variant of SARS-CoV-2 has been reported to have become the dominant strain of the virus in circulation around the world,” GISAID reported.
“There is still no definitive evidence showing that carriers of the G614 variant are actually more transmissible than those with D614 and the mutation does not appear to substantially affect clinical outcomes as well,” the Philippine Genome Center added.
The research facility said that “considering the presently wide geographic spread of G614, continuous monitoring of the said mutation – and other frequently observed mutations for that matter – must be done in order to better understand the evolutionary trajectory of SARS-CoV-2 to inform containment, diagnostic, and therapeutic strategies.”
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