Highly promising early effectiveness data for a single dose of the Pfizer and Oxford AstraZeneca vaccines from Public Health England

Early estimates of the effectiveness of the Pfizer and Oxford AstraZeneca vaccines by Public Health England. Data shows efficacy against symptomatic COVID disease (confirmed by positive test). This data was based upon people vaccinated who wee aged 70or over.

Pfizer vaccine demonstrates an estimated Efficacy of 61% between 28-34 days after 1st dose. Oxford AstraZeneca vaccine has an estimated Efficacy of 73% from day 35 onwards.

Some of these estimates have fairly wide confidence limits but it is undeniably brilliant news to see both vaccines being so effective after just a single dose.

On top of the protection against symptomatic disease, cases who had been vaccinated with one dose of Pfizer had an additional 43% lower risk of emergency hospitalisation and an additional 51% lower risk of death.

Cases who had been vaccinated with one dose of Oxford AstraZeneca had an additional 37% lower risk of emergency hospitalisation. There was insufficient follow-up to assess the effect of Oxford AstraZeneca vaccine on mortality due to the later rollout.

Combined with the effect against symptomatic disease, this indicates that a single dose of either vaccine is approximately 80% effective at preventing hospitalisation and a single dose of Pfizer vaccine is 85% effective at preventing death with COVID-19.

The report concludes that a single dose of the Pfizer vaccine is approximately 60-70% effective at preventing symptomatic disease in adults aged over 70 in England and 2 doses of this vaccine are approximately 85-90% effective. The effect of a single dose of the Oxford AstraZeneca vaccine against symptomatic disease was approximately 60-75% after a single dose, with insufficient data available to determine effectiveness of two doses of this vaccine.

Pre-print of report can be found here >> https://khub.net/documents/135939561/430986542/Early+effectiveness+of+COVID+vaccines.pdf/ffd7161c-b255-8e88-c2dc-88979fc2cc1b?t=1614617945615

One thought on “Highly promising early effectiveness data for a single dose of the Pfizer and Oxford AstraZeneca vaccines from Public Health England

  1. Thank you for including the link.

    I was thinking the last few days about a question, I’d very much appreciate your opinion on.
    According to the german press many of the participants of the Phase III study of the Astrazeneca vaccine took Acetaminophen prophylactically or after vaccination (https://www.br.de/nachrichten/deutschland-welt/impfstoff-studie-daempfte-astrazeneca-die-nebenwirkungen,SNqaY2F).
    Previous studies on intake of Acetaminophen or NSAIDs showed that this could reduce efficacy of vaccines (10.1016/S0140-6736(09)61208-3). And also a study showed that the intake of NSAIDs during a natural COVID-infection dampens the antibody response (10.1128/JVI.00014-21).
    As far as I know, Astrazeneca didn’t publish any data on Acetaminophen intakte during their Phase III study. The following study (10.1016/j.chest.2021.01.080) tells us: “A recent report from the ½ single-blind randomised trial of the
    AstraZeneca (adenovirus-vectored vaccine) does mention that prophylactic use of acetaminophen did not interfere with the vaccine’s immunogenicity although no data were provided”. But I couldn’t find any more information on this.
    The head of the german vaccincation comission Prof Mertens once mentioned in an interview that the side effects of the Astrazeneca vaccine were not as common as they now occur in Germany. Unfortunately this data is not public. This might point to more intake of Acetaminophen during the Phase III study than we see in reality. And also the vaccine efficacy in the Phase III study was not as high as in the following data.

    Do you think that intake of Acetaminophen or NSAIDs might dampen the vaccine efficacy of the Astrazeneca vaccine? Or also of the other vaccines?
    The study I cited above (10.1016/j.chest.2021.01.080) is also following this question, but they don’t come to a clear answer.

    Like

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