Travel freedom for the “double-jabbed”?
When the details of the UK government’s “traffic light” system for reopening travel were published, the two big criticisms levelled against it were the level of testing that was still required, even for green routes, and the lack of any differentiation between vaccinated and unvaccinated people.
The system relied heavily on infection rates. As we have seen recently here in the UK, that can change quickly and lead to start/stop gyrations in travel restrictions which make planning impossible for both travellers and travel businesses. That is especially the case if the thresholds are set at very low levels. Having been criticised for not being restrictive enough on travel early in the pandemic, the government has switched to a “safety first” approach. In practice, that has meant a traffic light system which is stuck on amber and red.
Whilst some might say that all we need to do is be patient and wait for case numbers to fall across the world, the UK may not have a travel industry left by that time, unless the Treasury provides a level of assistance that it clearly has no intention of doing. UK citizens are also increasingly asking why, if the vaccines are so effective, being fully vaccinated is not providing them with any increases in freedom?
Many feel that the time has come to look at a different approach. One that is more based around the risk of an individual, rather than being purely based on the average risk of the country they are coming from. That would be much more aligned with the approach that other countries are taking.
A policy based on vaccination status
The vaccines are estimated to provide 55-70% protection against infection after one dose and 70-90% protection after two doses, according to this paper from Public Health England (PHE). The same paper also looks at the impact of the Delta variant, with protection against symptomatic disease falling by 17 percentage points after one dose and 8 points after two. So I’m going to take what I think is a conservative approach and assume one dose gives 40% protection against infection and two doses gives 70%. (Update: this paper from the COVID Symptom Study shows an infection risk reduction of 59% for one dose and 87% for two, suggesting these assumptions are very conservative).
Let’s look at what this tells us about likely infection rates within the EU split by vaccination status. The current case rate in the EU is 31.0 weekly cases per 100,000. 20.1% of people have received just one dose and a further 24.7% of people have received two doses. Using the estimated factors for the level of protection against infection and a bit of maths, we can unpick the average case rate into the likely figures by vaccination status as follows:
Status |
% of population |
Case rate |
|---|---|---|
| Unvaccinated | 55.3% | 41.5 |
| Single dose | 20.1% | 24.9 |
| Two doses | 24.7% | 12.4 |
| Weight average | 100.0% | 31.0 |
So a policy of allowing only “double-jabbed” people to come into the UK from the EU without quarantine would be the equivalent risk to allowing a random person from a country with a case rate of 12.4, a long way below the 32.7 rate that Portugal had when it was added to the green list, and a lot lower even that the 20 per 100,000 rate that applied last summer.
It gets better
But wait, it is better than that. The PHE paper we looked at before shows that even for an infected person, the vaccines provide a further benefit. They reduce the risk of that infected person spreading the disease, which is the primary risk the UK is concerned about when it comes to travel restrictions. So far, only the transmission risk reduction after a single dose has been estimated, and that shows a reduction of 35-50%. It ought to be higher after two doses. But let’s be conservative again and use a figure of 40% for people who’ve had either one or two doses.
We can now add a “Transmission Risk (TR) adjusted” case rate column to our table, as follows:
Status |
% of population |
Case rate |
TR adjusted Case rate |
|---|---|---|---|
| Unvaccinated | 55.3% | 41.5 | 41.5 |
| Single dose | 20.1% | 24.9 | 14.9 |
| Two doses | 24.7% | 12.4 | 7.5 |
| Weight average | 100.0% | 31.0 | 27.8 |
Let me explain what these figures mean. A policy of waiving quarantine and all testing requirements for double-dosed arrivals from the EU would be equivalent to doing so for everyone arriving from a country where no vaccination had been carried out and which had a case rate of 7.5. The UK had that policy last summer with a threshold of 20 per 100,000. So this would be a policy that has only 37.5% of the risk the one the UK ran with last summer.
Or let’s compare it to the risk of adding Portugal to the green list only a few weeks ago. Portugal’s weight average, transmission adjusted, case rate was 30.3 when it was added. So classifying all fully vaccinated travellers from the whole EU as “green” would be only a quarter of the risk that the government was prepared to take less than eight weeks ago by classifying all arrivals from Portugal that way.
I think a single test only catches 60-70% of cases, so dropping one of the tests (either the pre-departure or the post arrival test) would still make this a lower risk policy than the previous one.
Other advantages of a switch to focusing on vaccination status
There are several other important advantages that such a policy would bring.
Firstly, it gets away from the start/stop problem, since people don’t become unvaccinated as time goes by.
Next, it automatically allows a progressive opening up of travel as vaccination programmes move forward. Because vaccination programmes are more predictable than case rates, it helps airlines and travellers to plan with much more confidence.
Finally, it also provides an additional incentive for people to get their vaccinations. Vaccine hesitancy will soon start to become the limiting factor rather than supply, even in countries like the UK with high take up rates.
That’s a benefit that might even appeal to the advisors who are focusing purely on the public health risk side of the equation.
