Delaying second COVID-19 vaccine doses will make supplies last longer but comes with risks

Delaying second COVID-19 vaccine doses will make supplies last longer but comes with risks

Drugmakers are facing challenges in manufacturing vaccines and building supply chains to meet the demand for COVID-19 vaccines. Pfizer has even lowered production targets. Scarcity of vaccines has prompted calls for a Band-Aid-like strategy to stretch the precarious supply.

To protect as many people as possible from COVID-19, the U.K.‘s medical officers have chosen to prioritize distribution of a first vaccine dose to as many people as possible – by delaying the second doses of the Pfizer/BioNTech COVID vaccine up to 12 weeks from the recommended 3-4. President-elect Biden wants to release all vaccine doses to speed up the vaccination program – but the risk is that vaccine makers won’t be able to replenish the supply to make sure that the second dose is delivered on time.

These decisions have opened up a rift between experts because some support giving a single vaccine dose to as many people as possible, while others want to vaccinate according to the protocol used during the clinical trials. In the U.S. only around a 10th of the 300 million doses promised by January under Operation Warp Speed are actually available.