![]() Given this change in dosing schedule deviates from our preference of a strict evidence-based approach, we have called on the government to ensure the following is implemented: Concerns over hypothetical consequences of putting the virus under pressure from non-sterilising vaccine regimes have to be balanced against a view of what we would face through the virus spreading at the current rate in our communities. 7 Any risks from actions taken now must be balanced against risks of actions not taken. ![]() Modelling data has shown that vaccination has by far the largest chance of reducing the disease burden and death rate compared with other measures. With the number of cases and deaths continuing to increase at a significant rate, we need to protect as many vulnerable people as possible from severe COVID-19 disease in the short-term. This increase in case number means our hospitals are experiencing very high admission numbers, leading to pressure on our healthcare system. Pragmatism. The SARS-CoV-2 virus continues to spread despite the societal restrictions introduced so far.We also would not expect any specific safety issues to arise for the individual due to delaying the second dose, other than an increased potential risk of disease during the extended period due to lowered protection. Expert opinion. Most immunologists would agree that delaying a second ‘booster’ dose of a protein antigen vaccine (such as the two approved COVID-19 vaccines) by eight weeks would be unlikely to have a negative effect on the overall immune response post-boost.Close monitoring of the vaccinated population will now be needed in order to garner further evidence. 6 There is no suggestion by the government that the second ‘booster’ dose should be extended any longer than 12 weeks. There is no current evidence that either of the two approved vaccines can prevent infection by the virus (rather they stop disease), so any concerns that delaying a second dose would have adverse effects on virus transmission remain hypothetical. There is also some evidence from the Oxford/AstraZeneca vaccine that this approach may be beneficial. 3,5 The exact relationship between the immunology and the disease protection data is uncertain but the Chief Medical Officers and the JCVI have noted that, by taking all relevant issues and data into consideration, more people can be protected from symptomatic disease in the short-term by extending the second dose up to 12 weeks. The phase 2/3 trial data show how many people are protected from symptomatic disease after the first dose by the Pfizer/BioNTech BNT162b2 vaccine. 4 The current government policy is that the second dose should be delayed from 3 or 4 weeks to 12 weeks maximum, not that people should not receive the second dose. 1,2,3 Similarly, the Oxford/AstraZeneca vaccine shows substantial immunological differences after the second dose at 28 days. Evidence based decisions. For the Pfizer/BioNTech vaccine, the immunology from preclinical to phase 2 trials shows that better neutralising antibodies and T cell levels are achieved after the second dose.Our reasons for this can be summarised as follows: Given this, although we would prefer the original dosing schedules tested in the trials to be used clinically, we recognise that a pragmatic approach in the short-term is needed, and accept the rationale for the change in dosing schedule for the Oxford/AstraZeneca and for the Pfizer/BioNTech vaccine that has been recommended by the Joint Committee on Vaccination and Immunisation (JCVI). We have an extremely challenging few months ahead with high levels of SARS-CoV-2 circulating through our communities together with the emergence of the new, more transmissible variant resulting in extra pressure on healthcare services. However, we also recognise that the UK now faces an unprecedented situation. ![]() ![]() Our priority is always to see that COVID-19 vaccines are rolled out in a manner that maximises safety and protection while minimising serious disease. ![]() As the professional body representing scientists and clinicians who study the immune system, the British Society for Immunology places the utmost value on an evidence-based approach to medical decisions. ![]()
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