A week ago. the Sunday New York Times was in full celebration mode, festooned with plenty of photos of packed indoor and outdoor activities, open restaurants, bars and theatres, admittedly with some residual distancing and a few masks – but a declared victory nonetheless for a city devastated by COVID a year ago.

The same celebratory mood was evident elsewhere in the United States, even in some places still smarting from too many active cases and deaths.

Many had had enough of isolation, shuttered businesses, bleak roll calls of spiking cases and deaths and finger-wagging calls to get vaccinated.

Still, there were real victories: the numbers were coming down and half the country had received at least one shot. In Canada, although case numbers were still high, they were coming down and Canadians could be justly proud that most had received at least one shot. With more vaccine on hand, the number of those completely vaccinated is climbing and younger age groups are now included.

But there were some canaries in the mine, which warned of trouble to come prompted by the appearance of new variants of concern. Early members included the U.K. (Alpha) variant, the Brazilian (Gamma) variant of which there are now at least two sub-variants, the South African (Beta) variant and, now, the Indian (Delta) variant of which there are now three sub-variants.

It wasn’t so many weeks ago that horrendous images from India reminded the world what can happen when a health care system collapses for want of resources to corral a raging pandemic made much worse by crowding and shortages of health care staff, facilities, oxygen, drugs and vaccines, and especially, the appearance of the dangerous new Delta variant.

It turned out to be 60 per cent more transmissible than the U.K. variant, which itself was 50 per cent more transmissible than the original SARS-CoV-2 virus. So infectious is this Delta variant, that it’s prevalence in Scotland and the U.K. surpassed its U.K. predecessor, which just months ago, fuelled the second gigantic waves in Europe, the U.K. and much of North America.

That’s why getting as many people vaccinated as soon as possible is so important. Without a majority of the population fully vaccinated, we could be in real trouble with the Delta variants or others emerging, yet unknown in pandemic hotspots throughout much of the poor and undeveloped incubator regions of the world.

Just look at what’s happening in Nepal these days. It’s scary.

So far, we’ve been comparatively lucky because our vaccines appear to be effective against all known variants; although perhaps less so for the Beta and Delta variants, especially for those less capable of mounting effective enough immune responses to ward off severe enough infections to warrant hospitalization.

And the latter is really the important question because in the real world, what’s important is protection against moderate or severe infections, not neutralizing antibody levels, as interesting and important as such biological markers might be.

As of mid-June, there were at least 10 variants of known high risk. But, almost certainly, there are many more subvariants of known variants and many other brand new variants yet to be identified.

As I’ve pointed out before, this is an arms race between a virus that continues to mutate in millions of hosts worldwide and a defence that depends on highly successful, simple public health measures such as mask wearing, social distancing and restricting contacts to known bubbles, worldwide genomic intelligence to quickly identify and characterize emerging variants and monitor their spread, and vaccines to protect us from serious life-threatening disease.

By and large, given the magnitude of the challenge, we’ve done well, despite the opposition of some to those same public health measures, the reluctance of many to be vaccinated, vaccine shortages and spotty genomic surveillance. Thank goodness for the United Kingdom’s work on the last.

But before we take a victory lap, it’s important to realize this battle isn’t over by a long shot. Left to mutate out of control, recent history on this virus suggests that it’s only a matter of time before variants evolve that are capable of evading our current vaccines.

Vaccine manufacturers such as Pfizer-BioNTech and Moderna and others, continue to track the evolution of the virus’ genome, especially for worrisome variants. Without too much trouble they can modify their current vaccines to keep them up-to-date and possibly introduce modified booster shots several months or possibly a year following the second shot. That makes a lot of sense to me.

The biggest success story of this pandemic has been the rapidity with which highly effective vaccines were developed using widely differing technologies in so many countries. If there were problems with the vaccines, they turned out to centre on scaling up production to many millions of doses and figuring out the best way of equitably distributing available vaccines to those most in need, as quickly as possible.

COMING UP: “What Worked, What Didn’t Work and What the Future Holds for the Pandemic” is the subject of the next Infohealth program on July 7 at 11 a.m. via Zoom. Plan to sign up with the Niagara-on-theLake Public Library and bring your questions.

Here are a few from the Journal Nature to consider: How well do the vaccines work in the real world? How effective are the vaccines against variants? How long does protection against disease last? How much do vaccines block transmission? What have we learned about safety? What impact have the vaccines had on the course of the pandemic? What’s long COVID about anyway?

Dr. William Brown is a professor of neurology at McMaster University and co-founder of the Infohealth series at the Niagara-on-the-Lake Public Library.