Covishield COVID-19 vaccine maker Serum Institute of India (SII) has bought a 50% stake in Schott Kaisha, the largest maker of vials in India. Schott Kaisha is a 50:50 joint venture partnership between German specialty glass producer Schott and India's Kaisha Manufacturers. SII's CEO Adar Poonawalla said the deal will ensure an uninterrupted supply of essential pharma packaging products.