Why have Nifty Pharma stocks like Aurobindo, Cadila and Reddy Labs been consistently hitting highs in the market?

On Friday, most of the major pharma stocks like Aurobindo Pharma, Reddy Labs and Cadila rallied by up to 5% on the NSE. The overall Nifty Pharma index rallied over 3% to touch an all-time high, reversing most of the pain of the last 5 years. Some specific pharma stocks like Marksans and Novartis were locked in 20% upper circuit. The reason has been the expectations of continued demand in the light of the resurgence of one more variant.