NEW YORK • Three Nordic countries are among only seven economies that did not slip into the bottom half of Bloomberg's Covid Resilience Ranking in the past 12 months.

The ranking weighed indicators among 53 economies for a year now, with the best and worst places to be during the pandemic. This was done by combining data ranging from outbreak control to death tolls, vaccination campaigns to progress on restarting travel.

Twelve months of the ranking have made one thing clear: past performance is no guarantee of future success - or failure.

The economies ranked have been stymied again and again by the vagaries of the biggest health crisis in a generation, but some have also found ways to turn devastating situations around, whether through science, social cohesion or simply learning from the past.

Since it debuted last November, the ranking's best and worst performers each month have fluctuated, with the onset of vaccines, the emergence of the Delta variant and the more recent reopening push among key moments in the pandemic journey.

Initially, the top performers among the 53 economies ranked were those which deployed tough containment strategies, including quarantines and border curbs.

Then, places that were able to roll out vaccines the fastest came to the fore, with those that have been able to combine high vaccination levels with a normalisation of social and economic activity now scoring highest.

As more potential turning points loom - lockdowns are returning in some places and the advent of Covid-19 pills could neutralise the virus over the long term - Bloomberg scored a year's worth of Covid-19 resilience.

This was done by zeroing in on the most consistent performers, who has done best on reverting to normal life and the ultimate indicator: where deaths have been most effectively avoided.

The pandemic's volatile arc meant that no top performer sustained their success all year.

New Zealand and Singapore, once No. 1 for walling out the virus and maintaining a level of pre-pandemic normalcy for most of 2020, saw their fortunes plunge as Delta infiltrated their Covid-zero fortresses, triggering renewed lockdowns and restrictions.

The United States - fleetingly at No. 1 in June - and Israel, the fastest at rolling out vaccines and lifting curbs in the early months of this year, were caught out when the coronavirus flared again over the summer, particularly among the unvaccinated.

The ranking's lower rungs fluctuated too: Countries such as Mexico and Brazil were ranked lowest through early 2021 as the virus slammed their populations, but Latin America has avoided the worst of the Delta variant, thanks to vaccination and a high level of natural immunity.

Meanwhile, South-east Asian countries took over as the worst places to be in the second half of the year as their inoculation roll-outs fell behind, with resurgent outbreaks leaving their export-dependent economies reeling.

Amid the flux, a handful of places proved the most consistent. Most of them never reached No. 1 of the 53 economies ranked, but they never fell below 26th place either.

These seven economies - Norway, Denmark, Finland, the United Arab Emirates, Canada, South Korea and Switzerland - are the closest the pandemic has to season MVPs (most valuable players): whether rolling out vaccinations, fighting Delta or reopening the economy, they always scored above average.

Strong healthcare safety nets and societal cohesion are common denominators among the seven, qualities that advantaged them at every stage of the pandemic.

At the other end, nine countries - Argentina, Iran, Mexico, Brazil, Peru, Poland, Nigeria, Pakistan and South Africa - have never risen above the ranking's mid-point in the past year.

These places have been the most devastated by the pandemic, infections-wise, and many still struggle with limited access to vaccines.

The northern hemisphere winter may again reshuffle the ranking leader board as countries confront the first cold season with both vaccines and the more transmissible Delta strain. Already, European nations like Austria, Germany, the Netherlands and Denmark are seeing fresh waves.

BLOOMBERG