As we’ve all learned the hard way with B117, which originated from the southeast of England, the adaptation of a novel virus into more transmissible and virulent forms is a real process with real consequences.
For most people, such an eventuality may have sounded like a storyline from a low-budget sci-fi movie until well into 2020.
Indeed, many of us supposed experts were dubious about the epidemiological significance of B117 until Public Health England released the viral population dynamics analysis that sent us all back to our modelling drawing boards.
The biggest and most urgent question we had to reopen was whether this evolutionary quantum leap made Covid uncontainable with the public health measures we had available to us at the time.
Fortunately, B117 is containable and outbreaks of this variant have been repeatedly snuffed out in countries like Australia and New Zealand that operate zero-tolerance policies towards Covid transmission.
Even more reassuring has been the way regional public health teams in Ireland have tackled even more worrisome variants that have gained an unwelcome foothold here.
Unlike B117, the Brazilian P1 variant has been kept in check despite being even more contagious.
The fading population-wide immunity generated by the first wave enabled accelerated evolution of the new variant.
The misfortunate people of Manaus thought they had seen the last of Covid but the second wave driven by P1 swept through the city even faster and harder than the first, taking a mere two months to peak and subside with grim consequences.
Within another two months, P1 had overwhelmed health systems across most of Brazil.
P1 appears more transmissible than B117 and just as virulent, so I’m mightily relieved to see it in decline here in Ireland since we introduced Mandatory Hotel Quarantine (MHQ) for several Latin American countries.
This not only proves that we can stem the flow of new seed cases coming in from abroad, but also that our public health teams can decisively shrink established outbreaks down to size.
Recent changes to give HSE regional public health departments greater autonomy and resources to allow them to play stronger leadership roles have been key to that success.
A crucial part of that enhanced response has been the walk-in testing centres that sensibly bend the silly rule about excluding children and attendees with symptoms.
Thinking beyond our struggles to crush Covid in the weeks and months ahead, let’s remember that we will need these regional public health teams to remain on standby for years to come, ready to deliver spring-loaded emergency responses whenever needed.
If continued evolution of the virus around the globe takes a wrong turn, we will need them more than ever before, so let’s not repeat last summer’s tragic mistake of standing down contact tracers when we thought the pandemic was over.
Also, let’s not underestimate the role of MHQ in both limiting the influx of new variants and giving our public health teams a fighting chance to deal with those already here.
While I’ve yet to see convincing evidence that the new Indian variant is more transmissible or virulent than P1, that’s not saying much.
Both variants have inflicted deep trauma on countries where they have become established.
The ongoing rampant spread of the Indian variant on our doorstep represents an unprecedented threat, presenting us with some stark choices we’ve been putting off for too long.
The bottom line is that if we’re serious about using MHQ to protect ourselves against more dangerous Covid variants, we will have to now apply it to our nearest neighbours in the UK and Europe with whom we share a long-standing common travel area.
If we don’t, MHQ is little more than a speed bump for such contagious new variants.
A particular concern for me has been the well-intentioned but risky delays in administering second vaccine doses in the UK.
While this accelerates the scale-up of vaccine coverage, it also presents the virus with opportunities to continue evolving.
While none of us can tell where those evolutionary processes will take us, all significant new variants we’ve seen so far represent incremental evolutionary steps toward increased transmissibility, usually accompanied by increased virulence and at least some ability to evade immune responses against its predecessors.
The worst-case scenario in which something as transmissible and virulent as P1 or the Indian variant emerges that can routinely evade our vaccines may never happen, but it’s not impossible.
WHO has described that likelihood as “when, not if” but I’m not so sure. Having said that, I certainly slept better after listening to a convincing report from Singapore about their experiences with an outbreak of B.1617.2 in Tan Tock Seng Hospital. Although the index case had been fully vaccinated and several cases occurred among vaccinated staff and patients, none of them progressed to severe disease. Unfortunately, not all of those infected who had yet to be vaccinated were so lucky.
Small numbers of breakthrough infections occur with even the most effective vaccines, so insisting on vaccination for air passengers will slow but not entirely stop the international spread of new variants.
However, full vaccine coverage will really swing the odds in our favour, allowing us to stamp out transmission one country at a time and then start to normalise travel between Covid-free countries.
In the meantime, sun holidays overseas will have to wait and real security against new variants will come sometime next year in the form of second-generation vaccines targeting two or more viral antigens.
If want to ride out this storm in the meantime, we need to urgently scale up MHQ to include all countries with ongoing transmission.
And given our geographic circumstances, we also need to quickly develop the kind of trailer exchange and border bubble systems used so effectively to prevent spread across state lines within Australia through surface trade and travel.
The biggest threat to Ireland isn’t far-away places like Brazil and India. Our first wave was seeded from Italy, not China, and our second from all over Europe.
The tragically avoidable third wave we’re still struggling with is dominated by B117 from the UK and most cases of P1 and the Indian variant in Ireland likely arrived via Paris, London or Amsterdam.
Our Achilles heel is our open borders with our nearest neighbours in the EU and UK. Given what’s happening on our doorstep, the time to act is now.
- Gerry Killeen is Chair of Applied Pathogen Ecology, School of Biological, Earth & Environmental Sciences and the Environmental Research Institute, University College Cork