Are vaccine passports being used in other countries in an attempt to cut Covid infections – or to try and boost vaccine take up by curtailing the social lives of those who refuse? The latest change in policy in Austria would appear to confirm that for them, it’s the latter. From today, access to restaurants, bars and any event with more than 25 guests will be limited to people who can prove they have been fully vaccinated, that they have previously recovered from Covid or that they have had one jab and a negative PCR test. In four weeks’ time, only the double-jabbed and those who can show they have recovered from Covid will be allowed in.

Austria, like many EU countries, has had a vaccine passport scheme for several months. But, until now, the unvaccinated could still access bars, restaurants and events – providing they could show a recent, negative Covid test.

You can understand why Austria might want to take action against a rising number of Covid infections, which have spiked to 10,000 a day over the past couple of weeks: a higher rate of recorded cases than at any point during the pandemic. However, it is also true that there are many valid arguments against vaccine passports, such as that they create a two-tiered society. As Lara Prendergast wrote in the magazine back in February, they separate society into the ‘jabs and jab-nots’.

But step back from that debate, and Austria’s policy looks deeply illogical. If your principal aim was to reduce the rate of new infections you wouldn’t use vaccination status as a means of controlling access to crowded places; you would insist that everyone showed a negative test result – in other words, the exact opposite of Austrian policy.

Repeated studies have shown that while Covid vaccines are highly effective at preventing serious illness and death, they are much less good at preventing asymptomatic infection. A recent study which was based on the use of the Pfizer vaccine in the Qatari population showed that efficacy against infection peaked at 77.5 per cent a month after the second dose – and fell to just 20 per cent after five to seven months. But the jab remained highly effective against serious disease, with efficacy at around 96 per cent after six months.

In other words, while there are strong incentives for a government to persuade its population to be jabbed, barring the unvaccinated from crowded places is not going to significantly slow the infection rate. The bars and restaurants of Vienna will still be full of customers capable of spreading the virus.

With Austria’s vaccination rate lower than that of many other European countries (64 per cent are double-jabbed, compared with almost 80 per cent in the UK), it is easy to see why the government would want to boost it. But the trouble is that people can see through illogical policies. In trying to encourage vaccination, Austria might end up merely encouraging contempt for the rules.