A real-world test of Pfizer’s COVID-19 vaccine in more than half a million people confirms that it’s very effective at preventing serious illness or death, even after one dose.

Wednesday’s published results, from a mass vaccination campaign in Israel, give strong reassurance that the benefits seen in smaller, limited testing persisted when the vaccine was used much more widely in a general population with various ages and health conditions.

The vaccine was 92% effective at preventing severe disease after two shots and 62% after one. Its estimated effectiveness for preventing death was 72% two to three weeks after the first shot, a rate that may improve as immunity builds over time.

It seemed as effective in folks over 70 as in younger people.

“This is immensely reassuring … better than I would have guessed,” said the Mayo Clinic’s Dr. Gregory Poland.

Vanderbilt University’s Dr. Buddy Creech agreed: “Even after one dose we can see very high effectiveness in prevention of death,” he said.

Eoin Treacy's view

This is very encouraging news for anyone worried that the pandemic is going to last indefinitely. There are a handful of variants currently spreading and each appears to be more transmissible than the original strain of COVID-19.

Some of the vaccines have not proven to be effective at managing these threats. However, the big step in calming consumers has been achieved. If a vaccine can be created to deal with the first one, a booster can be delivered to the deal with the next. That’s true in addition to the fact that most young people have little to worry about anyway.

The prospects of a much quicker reflation that most anticipate is the base case. That’s the signal from strength in asset prices, commodities homes and second hand cars.