As Matt Hancock said in a webinar to me, if you have four grandparents and only four vaccines, do you vaccinate all four or do you just vaccinate two? 

This is a question which we have all been asking and the government appear to have answered. 

However, the Sunday Times this week appears to suggest there is now evidence which has justified the delayed second dose approach.  

Professor Antony Harnden, Deputy Chairman of the Joint Committee on vaccination and immunisation, said people who have been vaccinated are enjoying high levels of protection from the first dose, which was hence reducing infections and saving lives. 

Public Health England is expected to publish this data within days.  By 6 February, 11 million people have been vaccinated in the United Kingdom.  The data appears to show that infection rates in the over 80s has fallen dramatically in the past month. 

The medical profession has criticised the UK’s approach, which was the delayed second dose for 12 weeks to accelerate the rollout.  The WHO has said the second dose of the Pfizer vaccine should only be delayed by up to six weeks.  

In view of the government’s approach, Britain has been able to get more people vaccinated sooner.  Anthony Harnden said “The COVID-19 vaccine role out in the United Kingdom is nothing short of a triumph – The Government’s strategy to extend the interval between the two doses means we have been able to protect more people and undoubtedly save more lives.  We have seen promising evidence that people get high levels of protection from the first dose”.  He described news that the Oxford AstraZeneca vaccine provided about 75% protection against COVID-19 and significantly reduced its spread after only one vaccination.  It suggests that the first Oxford dose provided protection for three months and may also stop transmission.  It shows evidence that the delayed second dose may provide better and longer term protection.  

In fact, according to a preprint with the Lancet posted on 1 February 2021, interim data suggested that the lengthening of the interval between vaccination dosage was associated with an increase in clinical efficacy.  In the standard dose group efficacy after the second dose was 82% at 12+ weeks, 55% at less than six weeks and antibody responses were more than twice as high after 12+ weeks compared to less than six weeks amongst those who are 18-55 years of age. 

It will be recalled that there was a mishap with calculating the concentration of study product and a subset of participants had received a lower dose of the vaccine for the first dose, about one half of the intended dose.  However, this did not affect clinical efficacy.  Additionally, a subset of participants elected not to receive the second dose and the efficacy of the sole dose of the Oxford AstraZeneca vaccine was 76% and protection did not decline during the three-month period following the initial vaccination.

Dr Paul Ettlinger

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