The efficacy of Covishield and Covaxin is likely to be tested against the Brazil and South Africa variants. The National Institute of Virology is isolating and culturing the South African variant in its lab. The NIV has already readied a culture of the Brazilian variant for testing. Serum samples from those who have received the vaccines will be used to test if they can neutralise the two variants. India has recorded four Covid-positive cases with the South African variant and one with the Brazilian variant.