The Medicines and Healthcare products Regulatory Agency (MHRA) has advised that the second dose of the Pfizer vaccine may be given between three to twelve weeks following the first dose, and that the second dose of the Oxford / AstraZeneca vaccine may be given between four to twelve weeks after the first dose.
Moving to a twelve-week gap is, therefore, within the bounds of the expert scientific advice received by the Government. Exploratory analysis has shown that a longer dose interval may actually increase immunogenicity from the Oxford vaccine; and while Pfizer has not evaluated an alternative dosing schedule, the Moderna vaccine, which uses the same mRNA technology, has data to support high efficacy up to 108 days after the first dose.
The short-term efficacy for the Pfizer vaccine is around 90%, and around 70% for the Oxford vaccine, so the Government’s first priority is for as many people as possible on the priority list to receive their first dose, in order to protect the greatest number of at-risk people in the shortest possible time, which will have the greatest impact on mortality and hospital admissions. This approach will maximise the number of people getting vaccinated, and therefore receiving protection in the following twelve weeks.
Our vaccination programme has been successful so far, and combined with the national lockdown, it has helped dramatically reduce COVID-19 cases, hospital admissions, and deaths. I am pleased that many people are now receiving their second doses, and NHS England have confirmed that we have enough vaccine supply to ensure that everyone who has received their first dose will receive their second dose within twelve weeks.