select search filters
roundups & rapid reactions
before the headlines
Fiona fox's blog

expert reaction to Covid pre-departure tests (and testing a sample of arrivals) for travellers to England from mainland China

The government has announced precautionary and temporary measures to improve COVID surveillance from China as COVID cases rise in China ahead of borders re-opening next week.


Prof Thomas House, Professor of Mathematical Statistics, University of Manchester, said:

“It is very natural to look at the enormous epidemic unfolding in China and assume that this has consequences for the UK, however we have high levels of both infection and immunity, meaning that any contribution of the Chinese epidemic to what we see in the UK is likely to be minimal.  Whether we should test some arrivals as part of surveillance is a more complex question, however it is worth noting that the capacity for such surveillance is always limited and so testing of travellers needs to be balanced against e.g. potential enhanced surveillance in our health and social care sectors.”


Prof Rowland Kao, Professor of Veterinary Epidemiology and Data Science, University of Edinburgh, said:

“Testing on arrival is not to prevent spread but to gather data – we know very little about what is happening in China.  If we and other countries are able to in particular gather viral sequences (via PCR tests) this will give us knowledge of what variants might be emerging in China.  No evidence of any new VOCs yet but for most other countries we’ve much better sequencing information – so this will fill an important gap.”


Prof Paul Hunter, Professor in Medicine, UEA, said:

“As regards point of entry screening:

“We have known from well before covid that point of entry/point of exit screening for infectious diseases is ineffective at controlling the international spread of infectious diseases  Even at the beginning of the covid pandemic such screening was shown to be of little value  I have read at least one newspaper report saying that this was the initial advice given to Ministers.

“As I understand it all travellers from China will still need negative tests to board a plane.  The point of entry testing was only ever intended to be a sample of arriving travellers in order to get more information on circulating variants in China, not as an attempt to control introduction of infections into the UK.

“Strict border control measures have been shown to keep infections out as shown by New Zealand and China.  But they have to be very strict and apply to all travellers not just those from the target country.  At the start of the pandemic the great majority of infections imported into the UK came from France, Italy and Spain and not China.  Anything less than that and at best border controls merely delayed infections not prevented them.

“Even if we did import infections from China, circulating variants in China are those we have in the UK and so are unlikely to have a big impact.  BF.7 was common in Western Europe 4 months ago but is already in decline.  BQ.1.* is still the dominant variant in the UK.  So border controls will not have much impact on these variants even if more introduced from China.

“The main future concern for the UK at present is the XXB.1.5 variant which was probably introduced into the UK from the United States and is now increasing.”


Prof James Naismith, Director of the Rosalind Franklin Institute, and Professor of Structural Biology, University of Oxford, said:

“Many people in the UK will remember loved ones being lost during the large UK waves and I hope we all have compassion for any human cost in the unfolding drama in China.

“China developed and deployed vaccines which were effective against the first strain and it to be hoped these vaccines will protect the vulnerable against severe illness from the new strains.

“In the UK 37, 000 people tested positive over the last 7 days with some evidence of an uptick.  This is a likely a very large underestimate of the number of cases.  ONS data (ending 8th Dec) estimated around 1.4 M people would have tested positive over the previous week (1 to 7th Dec).  These high numbers reflect the fact the UK is not taking steps to reduce transmission but is relying on vaccines and medicines to prevent serious illness.  The vaccines used in the UK are extraordinarily effective at preventing serious illness from the new strains, less than 100 people a day die in the UK with covid19.  The UK has a growing burden of long covid19.

“In a democracy, politicians not scientists take decisions on restrictions.

“From the perspective of case numbers the restrictions on Chinese travellers will have no discernible impact.  In the absence of internal measures to control spread, new variants once in the UK will spread quickly.

“New variants of covid19 continue to emerge here and abroad.  In a large wave such as may be underway in China new variants seem likely.  Almost by definition, a new variant which emerges in population will spread faster than the older variant in that population.  The speed of spread depends on the virus, the size of the susceptible population (related to total size and immune status) & social contact.

“There are two key questions about variants.

“How effectively does a new variant evade immunity?  The more immune evasive, the more infections will be seen in the vaccinated (& previously) infected population.  The UK has around 1 in 40 people infected, we have seen peaks around 3 to 4 times higher than this.  A return to such numbers would further strain the NHS.

“Is the new variant more likely to cause serious disease?  It is because of our immunity not because of the change in virus, that deaths are so low.  There was some evidence that the original Omicron strains produced lower number of severe disease, we do not know to what extent this remains true.  In any event, to date all the strains present a risk of serious disease in the unvaccinated and vulnerable.  There is no law of biology that new variants to be milder.  There is some evidence that repeated infection may have adverse consequences and it is too early to know what will happen with long covid with new variants.

“Can we keep new variants out?  This has not been possible to date in the UK and there is no evidence this is plausible for the UK.

“Can we do anything to reduce the risk?  Vaccinate and get boosted.  If you are infected or symptomatic, isolate at home if at all possible.  Improve indoor ventilation.  Universal mask wearing and / or social restrictions are effective but quite rightly are for politicians to decide on.  For the vulnerable, N95 masks properly worn do provide significant protection even where others do not mask.”



All our previous output on this subject can be seen at this weblink:



Declared interests

Prof Thomas House: “No conflicts of interest I can think of, except that I’ve been working on these issues.”

Prof Rowland Kao: “SPI-M membership, and Scottish COVID funding from the PHS Chief Scientist’s Office.”

Prof James Naismith: “No conflicts.”

For all other experts, no reply to our request for DOIs was received.

in this section

filter RoundUps by year

search by tag