US, EU say vaccine programs on track as global deaths hit 2.5 million
ঢাকা ট্রিবিউন
প্রকাশিত: ২৬ ফেব্রুয়ারি ২০২১, ০৯:০৪
In further vaccine developments, frozen vials of Pfizer's Covid-19 vaccine may be stored at temperatures commonly found in pharmaceutical freezers for up to two weeks
