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BSI response to preprint on the effectiveness of first dose of COVID-19 vaccines against hospitalisations in Scotland

22 February 2021

A new preprint study suggests a substantial reduction in the risk of COVID-19 admissions to Scotland’s hospitals after the first dose of the Pfizer/BioNTech and the Oxford/AstraZeneca vaccines. In response, the British Society for Immunology has released the following statement:


Professor Arne Akbar, President of the British Society for Immunology, said:

“The primary aim of all vaccination campaigns is to stop people getting seriously ill and save lives. This initial data reported in this preprint on the effectiveness of one dose of a COVID-19 vaccine is extremely promising. At 28-34 days after the first vaccine dose, hospitalisations were reduced by 85% in those who had received the Pfizer/BioNTech vaccine and by 94% in those that had received the Oxford/AstraZeneca vaccine.

“Although there does seem to be some difference in effectiveness levels measured across age groups, the reduction in hospitalisations for the older age groups is still impressively high. We now need to understand how long lasting this protection is for one dose of the vaccine. Although further research is needed, overall these new findings should provide reassurance around the UK’s decision to offer the two doses of the vaccine 12 weeks apart.

“While the results of this study indicate a good level of immunity after one dose, it is still the case that the highest and longest lasting protection from getting ill with COVID-19 will only be provided by getting two doses of the vaccine. It is critical that all people eligible for COVID vaccination do return to get their second dose when asked to do so by their medical providers.”


You can read the full press release here. This paper is a pre-print reporting preliminary data that has not yet been peer-reviewed. It is hosted temporarily with the University of Edinburgh until the permanent link becomes active. You can read it here. Vasileiou et al. 2021 Effectiveness of first dose of COVID-19 vaccines against hospital admissions in Scotland: national prospective cohort study of 5.4 million people. SSRN: https://ssrn.com/abstract=3789264.