British Vaccine Efficiency

The British vaccination plan has been run very well. As this audience knows, the British delayed the second dose in order to get out more first doses quickly. A life-saving move. The British have also been targeting age and riskier workers very well. The excellent Witold Więcek (an Emergent Ventures prize recipient) has done a back of the envelope calculation which indicates how well the British are targeting.

Since the vaccines have been prioritised for the elderly, the infection fatality risk (IFR) for a typical vaccinated patient is higher than the average IFR in the population. However, we have to account for the fact that many of the early doses are given to health care workers and some of the other key workers. By late February 2021, in the UK around 55% of the vaccines went to people over 70 and over 95% of that age group has been vaccinated. In the US, however, while 55% of vaccines went to people over 65, close to 30% went to people younger than 50. We calculated IFR as an approximate weighted mean of age-specific infection mortality risks, using a meta-analysis estimate in Manheim et al., 2021.

Applying this IFR approach to real-world distributions of vaccine distribution, for UK we obtained 4.7% and for the US 3.2%, a remarkable difference. In other words, despite delivering twice the number of doses (and “running out” of highest risk individuals to vaccinate), a single dose of vaccine in the UK was still used 50% more effectively than in the US. (It should be noted, however, that the UK has a slightly older population than the US.)

Given less centralized health information, it’s hard to see how the US could target much better while also maintaining speed which is why, after the first round of vaccinating the nursing homes and the very elderly, I have leaned towards opening up more vaccination sites and prioritizing speed. So read this as a credit to the British rather than a demerit to the US. Other European countries, however, also have more centralized medical systems and yet have been far behind the British. It has struck me during this crisis how little these kind of system-wide policy variable seem to explain in the efficiency of the pandemic response overall.


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