SILVER SPRING — The US Food and Drug Administration (FDA) on Wednesday (May 19) authorised storage of Pfizer and German partner BioNTech's Covid-19 vaccine at standard freezer temperatures for up to one month, in an effort to make the vaccine more widely available.

Unopened, thawed vials of the vaccine can be stored in a refrigerator at 2°C to 8°C for up to a month, up from a previous maximum limit of five days.

"This change should make this vaccine more widely available to the American public by facilitating the ability of vaccine providers, such as community doctors' offices, to receive, store and administer the vaccine," said Dr Peter Marks, director of FDA's Center for Biologics Evaluation and Research.

The change is especially important for global and remote US facilities that have poor transport and storage infrastructure.

In February, the US health agency approved the storage and transportation of the vaccine at standard freezer temperatures for up to two weeks instead of ultra-cold conditions.

Earlier in the day, Health Canada said it had approved storage of the vaccine at standard refrigerated temperatures for up to a month, to allow for more flexibility in distribution plans.

The vaccine was granted emergency use authorization in December with a label requiring it be stored at temperatures between -80ºC and -60ºC, meaning it had to be shipped in specially designed containers. REUTERS