To ask Her Majesty's Government what assessment they have made of the opinion expressed by consultants at St Bartholomew’s Hospital, as reported in The Times on 21 January, that delaying the second dose of COVID-19 vaccinations risks (1) lower effectiveness, and (2) viral mutation.
29 April 2021
We have made no such assessment.
Public Health England (PHE) is monitoring the effectiveness of the vaccines, including the effects of dosage schedules. Data from the programme shows the first dose of either the BioNTech/Pfizer or Oxford/AstraZeneca vaccine provides substantial protection within two to three weeks of vaccination. Additionally, data from PHE’s SIREN study shows that both these vaccines provide high protection against COVID-19 infections in healthcare workers after a single dose, beyond 56 days of having been vaccinated. The second dose completes the course and is vital for longer term protection. By the end of March 2021, it was estimated that a total 10,400 deaths were averted as a consequence of the COVID-19 vaccination programme.
PHE is conducting enhanced surveillance for the small number of individuals who may develop COVID-19 post-vaccination. This enhanced surveillance, including viral whole genome sequencing which detects viral mutation, can identify whether an individual did not successfully mount an immune response to a vaccination, or whether the disease presented despite evidence of an immune response to vaccination. Understanding these factors are an important part of ensuring the success of the vaccination programme and allows the Government to understand the evolution of new COVID-19 variants and respond swiftly.