Once COVID-19 vaccine vial opened, it needs to be used fully within four hours: Senior doctors

The first batch of Oxford COVID-19 Covishield vaccine had reached
Delhi's central storage facility at Rajiv Gandhi Super Specialty
Hospital (RGSSH) on January 12. The lot of Bharat Biotech-made Covaxin
had reached there the next day, which is being used at six sites,
including AIIMS and RML Hospital.

https://economictimes.indiatimes.com/industry/healthcare/biotech/pharmaceuticals/once-covid-19-vaccine-vial-opened-it-needs-to-be-used-fully-within-four-hours-senior-doctors/articleshow/80350543.cms