For most of us who have been sweltering in Ontario’s summer heat wave, the latest surge in infections in Israel seems too far away to worry.

But Israel may be the canary in the mine these days. Why? Because it has experienced an unexpected surge in infections this summer. 

The country has one of the best health care systems in the world, which began vaccinating its population with the Pfizer, Moderna and to a lesser extent AstraZeneca vaccines as early as December 2020, well before most countries. 

And as matters now stand, nearly 80 per cent of the population is fully vaccinated, including 87 per cent for those 70 years of age and older as well as children 12 and over. 

By any measure that’s a very impressive vaccination campaign and should provide a high degree of protection against spread of the disease and moderate to severe disease. With such a good record, the country began to open up. Then Delta struck.

Beginning this summer, infections in Israel began to tick upward – not a lot – but enough to worry scientists because the uptick involved, not just the unvaccinated, but some of the fully vaccinated, especially older Israelis. 

The latter prompted Israel’s scientists to wonder whether the protection provided by the vaccines was waning, especially among older citizens, who were among the first to be vaccinated and most at risk without vaccination of developing moderate to severe disease.

From the outset, virologists, infectious disease experts and epidemiologists were worried about how long the protection offered by vaccines would last. Would it last half a year, a whole year or more? 

Unlike the measles and polio vaccines, which offer lifetime protection, with one shot, recent evidence from Israel and elsewhere, suggests that controlling the worst of the SARS-CoV-2 virus might require regular booster shots, probably incorporating protection against the latest variants.

Genomic testing throughout the pandemic, much of it initially carried out by the U.K., revealed the virus was evolving, and sometimes in dangerous ways – hence several well-known “variants of concern” and “interest.”

Aside from the first variant to emerge in China, the best-known variants of concern have been Alpha, which surfaced in late 2020 and dominated the viral landscape early in 2021, and Delta, which emerged as the dominant variant this summer.

The Alpha variant proved to be far more transmissible compared to earlier variants and the Delta variant, much more so, which probably explains why the Alpha variant came to dominate compared to earlier variants and was in turn replaced by the even more adept and aggressive Delta.

But aside from the relative ease with which those variants spread, there was always another worry – were the Alpha, and now Delta variants, more dangerous – more likely to cause infections serious enough to warrant hospitalization compared to earlier variants? 

And closely related to that question was: To what extent do current vaccines protect against these variants and probably more dangerous future variants?

The evidence suggests that most vaccines provide excellent protection against developing serious infections, although less so for those over 70 years of age or those with weakened immune systems at any age. Even so, the Israeli evidence strongly suggests that protection wanes and booster shots will be required.

Breakthrough infections in vaccinated patients tend to be asymptomatic or, if symptomatic, no more than might be experienced with the common cold. 

Even so, occasional more serious infections develop suggesting that the first line of defence in the nose and throat was breached by the virus which spread to the lungs and other systems and organs. 

Those occasional breaches in vaccinated patients are probably related to waning immunity and possibly mutations that mask the spike proteins from the immune system or other mutations, which facilitate contact with and entry into the host’s cells. 

Those are all good reasons for booster shots and within a year, modified vaccines to take account of these more dangerous mutations. In the meantime, Israel took the right step.

The nation began booster shots for those 60 and over in July and 50 and over in August, roughly six to seven months following their first shot and using the same vaccines without as yet incorporating any new features to take account of later variants. The latter tweaks will probably follow.

Which is why I think we’re at a turning point in this pandemic. Everything seems back to normal or some crazy version of normal while the war goes on with a virus that continues to evolve in ways that might blindside us, such as the sudden appearance of more dangerous descendants of the Delta variant resistant to current vaccines. 

That’s the worry, for which booster shots of current vaccines offer a temporary answer. 

What’s needed in the near future will be continuously updated vaccines, approval for which should not take the long, laboured approach the first approvals took.

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.