Will the Covid tests imposed on travelers from China be effective?

• The dazzling epidemic recovery in China raises fears of the circulation of new variants on French territory.

• Paris will thus impose on Thursday the presentation of a negative test for Covid-19 to travelers coming from China.

• But can this measure really prevent the virus from circulating across borders?

  Answers with Yves Buisson, epidemiologist and president of the Covid-19 unit of the National Academy of Medicine and Catherine Hill, epidemiologist and biostatistician.

The epidemic outbreak in China is of great concern to other countries.

Since the lifting of drastic restrictions by Beijing in early December, the Covid-19 has been circulating exponentially in the country, raising fears of an epidemic resumption in the rest of the world.

This is why France has followed the initiative taken by the United States or Italy to impose a negative test carried out 48 hours before their flight on travelers coming from China.

The measure will be effective next Thursday.

Can this measure be effective?

Isn't it too late?

“It all depends on what the objective is”, answers

Yves Buisson, epidemiologist and president of the Covid-19 cell of the National Academy of Medicine.

Effective tests against a new variant?

It has been almost a month since China decided to loosen its restrictions on Covid-19, abandoning its “zero Covid” policy.

France, it will put in place next Thursday the obligation to present a negative test on arrival to travelers coming from China.

A measure a little late, according to Yves Buisson who believes that it should have been taken at the beginning of December.

But in any case, if the objective is to prevent a variant from entering the territory “we have it all wrong”, estimates the epidemiologist.

“We cannot prevent viruses from crossing borders, at most, with a quarantine imposed on arrival, we can slow down the spread,” he explains.

Catherine Hill, epidemiologist and biostatistician, and Yves Buisson insist that it is impossible to prevent a virus from crossing borders.

Especially since travelers can come from China by transiting through other countries, then arrive in France by escaping the compulsory test.

So a common European solution would undoubtedly make more sense, even if “it remains illusory because a virus is circulating, it is inevitable”, insists Catherine Hill.

For Yves Buisson, the control of tests remains an inefficient solution, "it's politics", he comments.

And to add: “Border controls are not scientifically justified, it is useless in terms of braking”.

Are we risking a new wave from China?

On the other hand, the variant of Omicron which has imposed itself in China, the BF.7, has already been detected in Europe.

Thus, for Catherine Hill, the variant is not so much to be feared because “it circulated without prospering among us”.

If it is so present in China, “it is because it is a very dense population in places and very poorly protected.

In France, we are generally vaccinated and many people have already caught the virus, which greatly limits the damage ”, she underlines at

.

In other words, “why would this BF.7 variant mutate more efficiently than the one we already have here when it has not supplanted the other variants elsewhere?

asks Catherine Hill.

Yves Buisson is more cautious because the variant's transmissibility rate in China is very high with a reproductive capacity (or R0) of 10 to 18.6.

A rate which can nevertheless be explained by the weak protection of the inhabitants of China against the virus.

If the BF.7 won in Europe, and therefore in France, we could fear a new wave, according to Yves Buisson.

Monitoring is therefore essential because "in China, all the conditions are met for the variant to continue to mutate", he explains.

Testing arrivals from China can thus prove useful in order to sample the variants likely to enter French territory so as not to be surprised by this phenomenon.

Tests are also carried out on arrival at random,

What measures should France take?

The Covid-19 still kills in France.

According to the latest figures from health authorities, an average of 117 people per day have died from the disease over the past week.

And yet, barrier gestures seem to belong to ancient history.

Yves Buisson thus believes that the public authorities should resume information and incentive campaigns to protect themselves and others from the virus "to avoid transmission, and this involves wearing a mask or barrier gestures" recalling that " the epidemic is not over”.

Our file on covid-19

But above all, we must resume vaccination campaigns, believes Catherine Hill.

Another 10.5% of people over the age of 80, those most likely to develop severe forms, are not vaccinated at all, according to Public Health France.

And while the fourth dose of the Covid-19 vaccine is open to everyone, less than 50% of people over 80 have received this booster dose.

“Everyone has to be up to date, that's how we reduce the risks,” claims Catherine Hill.

And even for those under 60, “you have to stay vaccinated,” insists Yves Buisson.

Especially since hospital services are already in a critical situation, facing a triple epidemic of Covid-19, influenza and bronchiolitis.

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