UK health officials also allowing combining doses from different manufacturers
UK health officials have decided to delay giving second doses of Covid-19 vaccines and even permit combining doses from different manufacturers, prompting international concern. What is the scientific justification for this decision?
Why has the UK decided to lengthen the gap between the first and second doses of vaccine?
The original plan was to offer priority groups an initial shot of vaccine, followed by a second dose three weeks later. But a rapid increase in the number of Covid-19 cases, combined with the emergence of a more transmissible variant and uncertainty about the supply of vaccine stocks, prompted the Joint Committee on Vaccination and Immunisation (JCVI) to consider other options. It calculated that it could get a first shot of vaccine into more arms faster if it pushed back administration of the second dose to 12 weeks afterwards – by which time it is hoped that far more doses of vaccine will become available. “This is highly likely to have a greater public health impact in the short term and reduce the number of preventable deaths from Covid-19,” a JCVI statement said.