An excellent vehicular analogy by Tim Harford, the economist, author, podcaster and Financial Times columnist. The debate he weights in on is whether it’s best to give as many people as possible the first dose of a two shot COVID vaccine, or hold back to make sure a smaller group of people get the second shot, according to the timelines recommended in clinical guidelines.

It’s an issue that was alive in Saskatchewan a few weeks ago.

Harford says with menacing variants increasing risk, the answer is obvious:

Cars are better with two headlights, and bicycles are better with two wheels. But while a bicycle with one wheel is useless, a car with only one headlight might be good enough in a pinch. The judgment here is that a single dose is more like a car with a single headlight than a bike with a single wheel. Given that these vaccines probably prevent the spread of the virus as well as preventing disease, it is possible that even people at the head of the queue might benefit if their second dose was temporarily redirected: if forced to drive in the dark, I would rather that every car on the road had one headlight than some two and some none. With a dangerous virus in wide circulation, we are all driving in the dark.

Source: Is ‘first dose first’ the right vaccination strategy? | Tim Harford