Well, that didn't last long. For a couple of months, it really looked like being double-jabbed might buy you a ticket to free (ish) travel. More than that, it was our only exit strategy from this vicious circle of lockdowns at home. But new evidence has thrown all this into doubt.

Anti-vaxxers will delight in this latest development: that being jabbed won't stop you spreading the extra-infectious delta variant after all. It certainly protects you personally, to a high degree, from serious symptoms and death – but the vast majority of us weren't at risk of that anyway. 

What it won't do, according to an increasing body of evidence, is prevent you from being a carrier and thus a danger to others. This somewhat defeats the whole point – and is certainly the only reason international travel has resumed of late. 

Last week, in news that hasn't got nearly enough airtime, Public Health England said in a statement: "Some initial findings […] indicate that levels of virus in those who become infected with Delta having already been vaccinated may be similar to levels found in unvaccinated people. This may have implications for people's infectiousness, whether they have been vaccinated or not."