Samples of anyone with a past history of Covid-19 who tests positive again, or those who catch the disease after getting two doses of a vaccine, will be mandatorily sent for whole genome sequencing, the Delhi government ordered on Thursday. The decision is aimed at augmenting surveillance to look for any concerning variants.
The decision comes a day after the Centre said it found the presence of a novel variant of Sars-Cov-2 in Delhi in nine samples, while 65 others had the UK variant B.1.1.7. It is yet to be established how the novel variant changes the nature of the virus, but it contains two mutations (E484Q and L452R) that could make it spread more readily or evade the immunity conferred by a past infection or a vaccine. The directorate general of health services (DGHS) directive also said that each district has to send 12 samples (three each of mild, moderate, severe and critical cases) of Covid-19 positive cases per week to the National Centre for Disease Control (NCDC) for whole genome sequencing. “This will help us in detecting which strain is causing most of the infections here – whether it is the new variant, other variants such as UK, South Africa or Brazil, or something else,” said a senior official from Delhi’s health department.