C-19: Early results from observing efficacy of current vaccine portfolios

Updated: Jun 16, 2021

In the last 6 months we have witnessed a scramble by all countries to immunise their populations against COVID-19. Given the collective race, country vaccine portfolios as they are today are thus much more a function of supply availability, rather than conscious curation. Europe for example granted first emergency use authorisation to Pfizer in late 2020, earlier than other options, in large part due to it having concluded clinical trials ahead of the rest. While there is a clear predominance of Pfizer in most early portfolios (as at June 2021 and ex-China), the US has supplemented supply with Moderna, and the UK with Astra Zeneca - respectively some 40-45% of their total portfolios. Given the differences in portfolio composition, it is relevant to ask whether there is visible difference in the results observed in each country. We explore the real world data here in this article and outline some key takeaways.

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Summary of observations (as at 12 June 2021);

  • Most European countries such as France, Italy, Germany, Spain, and Netherlands have large contribution in their portfolios from Pfizer (~70+ % of total)

  • Our forecast analysis of daily cases and deaths of these countries suggests that there is a clear two-prong impact from immunisation; (1) a gradual yet distinct roll-off in transmission once a threshold (of % vaccinated) is met, and (2) a gradual yet distinct roll-off in case fatality rate, up to 3-10x from baseline levels

  • Meanwhile, US and UK, while leading the charge in terms of immunisation progress (number, or % population vaccinated), have supplemented their portfolios significantly with other options; US with Moderna, and UK with Astra Zeneca - respectively consisting some 40-45% of their deployed portfolios

  • The US is only showing a mild tapering of virus transmission (when excluding mobility effects), since reaching a threshold of 20-25% vaccinations to population, however case fatality rates do not show the distinct roll-off seen in European countries

  • The UK on the other hand is yet to show a tapering of virus transmission (when excluding mobility effects), but instead exhibits a gradual yet distinct roll-off in case fatality rate

  • The Delta variant (Indian B.1.617) has now been detected in both the UK and US and there are tell-tale signs that neither country's portfolios are 100% robust to handle the spread of this variant; both are showing early signs of new waves forming

  • Note that the above observations do not factor in the sequence in rollout priority given to different population groups in each country. While most countries have opted to focus first on medical frontlines, the sick and older aged (see UK example below), in practice unequal discrimination from one country to the next could indeed explain the differences observed

Table: summarised vaccine effectiveness results based on analysis of COVID-19 cases and deaths across a number of countries

Figures: analysis of COVID-19 case and death statistics - Germany (example)

Germany: Daily case evolution and vaccine rollout progress - 70.5 vaccinations per 100 population
Germany: Death statistics exhibit a distinct roll-off in case fatality rate. Meanwhile transmission has continued to roll-off despite increased mobility. Latest CFR ~0.5% vs. overall average 2.4%

Figures: additional reference material sourced literature

UK current and future vaccine portfolio
European countries + US vaccine portfolios
UK priority groups for vaccine rollout
EU vaccine distribution by manufacturer (Statista)


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