Why are countries requiring Chinese travelers to be tested for COVID even though they have millions of cases within their own borders?

Question

Countries such as the UK, US, Italy, Japan, Australia, South Korea, Morocco, Israel, Qatar, India and Malaysia, have introduced COVID testing requirements on people arriving from China. However this seems to make very little sense given that these countries see millions of COVID cases every week (though only a small fraction gets a PCR test) and thus infected Chinese tourists shouldn't make a dent in the overall numbers. For example, in the US we have:

1. Total tourists from China to the US per year in 2019: 2.8m or 7.7k per day, which gives us a theoretical upper bound on how many tourists will actually end up coming to the US in January
2. Current official COVID cases in the US: ~50k/day. Note that these are only cases detected by PCR tests.
3. Estimated ratio of PCR-detected cases to actual cases is 1 in 14, so the US actually has 700k new COVID cases per day
4. Assuming a 50% positivity rate for tourists arriving from China (which was recently the case for a single flight to Milan), we can predict that at most 7.7k*0.5 = 3.8k new cases will be imported to the US from China per day
5. Thus we can predict that Chinese arrivals will increase the real case count by 3.8/700 = 0.5% at most. In reality the number will be lower because it's unlikely that 50% of each plane from China will be testing positive and tourist numbers won't immediately bounce back to levels from 2019.

Similar numbers can be derived for countries other than the US. So, what is the purpose of these restrictions? Have any government officials provided numbers to justify these measures?

This is not the same question as Why are countries still introducing COVID-19 quarantines for travelers from affected regions, even though it's been proven they don't work? because the world is no longer trying to contain the virus - instead we're told to "just live with the virus". Therefore, any new restrictions are somewhat perplexing.

Answer 1

If we're speaking purely in epidemiological terms there is at least one possible explanation. Foreign countries might be afraid of new variants emerging in China now after the restrictions were lifted and many Chinese citizens got sick.

Different countries perceive the threat differently, so, for example, Germany or Sweden might make different decisions than France or the USA. During the lockdowns/vaccine approvals/etc. different countries also had some differing decisions, even within the EU.

A bit more about the variants

Viral diseases are not only about the number of infected people. Viruses keep mutating while the disease spreads and they can get new features that can make them harder to treat or make vaccines less efficient. In theory, governments track the disease within their borders and inform the international community when something happens (say, a new viral disease starts spreading in Wuhan, or a new variant for an existing virus appears).

The longer the person is sick and the more people are sick, the higher the chances are for a new variant to emerge. The hard lockdown in China implied that relatively few people got sick until now. But now, there are likely dozens of millions of people being sick simultaneously without any previous exposure. If we pair this with a lack of trust in the quality of Chinese anti-Covid vaccines, we get a perception that there are very high chances of the emergence of new variants.

Edit - Official statements mentioning new variants

I was asked to share some public announcements about variants in the comments to this answer. So, to make the answer fuller here is one From the CDC (the USA):

Variants of the SARS-CoV-2 virus continue to emerge in countries around the world. However, reduced testing and case reporting in the PRC and minimal sharing of viral genomic sequence data could delay the identification of new variants of concern if they arise. Pre-departure testing and the requirement to show a negative test result has been shown to decrease the number of infected passengers boarding airplanes, and it will help to slow the spread of the virus as we work to identify and understand any potential new variants that may emerge.

Here's another one from Canada:

the World Health Organisation has pointed to the lack of a clear global understanding of the genomic sequencing of cases in China. That genomic sequencing has, in more recent times, at the very least, been shared largely in real time by other countries around the world and is critically important in the detection of new variants of the COVID virus. That lack of comprehensive information has led a number of countries in recent days to put in place various measures - not to restrict travel from China, it's important to say - but to gather better information about what is happening epidemiologically in that country.

It should be noted that not all countries mention variants. This is from Morocco. Please, note that they don't require testing or vaccination certificates but rather imposed a complete travel ban.

In the light of the evolution of the health situation related to Covid-19 in China, and of the regular and direct contacts with the Chinese side, and in order to avoid a new wave of contaminations in Morocco and all its consequences, the Moroccan Authorities decided to prohibit access to the territory of the Kingdom of Morocco to all travellers, regardless of their nationality, coming from the People's Republic of China.

Answer 2

Medical epidemiological considerations.

Covid in China is right now a fast-moving, unclear, situation. Trust in what the government is officially saying is limited.

There are reports of hospitals filling up with patients and a growing demand for funeral services.

But officially, China is reporting relatively low numbers of Covid cases and a tiny number of deaths.

Each suddenly sick traveller in a host country will stress that country's hospital staff and facilities, with, perhaps, a later recovery of those costs.

Variants are a part of that calculation too - they are likely to arise elsewhere, but the sudden inflection point in the Chinese covid procedures, coupled with the large population and a propensity to travel might make it somewhat more of a risk - (maybe? I am not all that convinced myself at the extra risk but have little to base that on) - more time to see how it plays out may bring some clarity.

Given some time, it is possible some of these restrictions will be revisited, even if the core Chinese situation doesn't change, just because there is a better understanding of what the sudden relaxation means. For now, China's covid situation is a bit of an unknown loose cannon.

A key reason that many countries are imposing Covid checks on travellers from China is the lack of surveillance data coming out of the country. The more Covid that is circulating, the more chance there is for the virus to mutate.

But new variants can pop up anywhere - the UK, Brazil, South Africa and India have all been the likely origins of previous variants of concern.

What goes around comes around

China has for the last 3 years been extremely, extremely, restrictive in its own procedures for admitting foreign visitors.

(Sep 2021)

Air travel remains the main way of entering the country but international flights to the country are limited. In March 2020, China restricted both foreign and Chinese carriers to just one weekly international passenger flight per airline.

(May 2022)

What are the restrictions?

As of May 20, travelers from the United States and Canada no longer have to take a PCR test seven days before flying to China. However, some restrictions are still in place. These travelers are still required to take two PCR tests 24-48 hours before going to China (depending on their departure airport) and a pre-flight antigen test. For the newly qualified entrants, entry depends on having received two doses of Covid-19 vaccines at least 14 days prior to entry. They must apply for a visa in advance, and show their proof of vaccination on arrival, as well as the negative tests. Arrivals are screened once more at the airport. Those failing the checks will be sent to government facilities. Some provinces require additional quarantine upon arrival. Would-be travelers must be careful as flights can be canceled at the last minute.

You can do all sorts of searches - China was very, very, bossy and restrictive. Yes, being so may very have been necessary because of their zero-covid medical approach, but it was still very restrictive.

It is not uncommon for countries to engage in tit-for-tat behavior when it comes to visas and other travel restrictions. There is a bit of an element of time differences making that unusual in this case: at times China may have had more of a good reason to be more restrictive. And, yes, Western countries have covid more under control right now, thus less reasons for restrictions.

Yet, the general point stands: the amount of restrictions on Chinese travelers in the midst of an outbreak of unknown severity in China is minimal compared to what China maintained on foreign visitors - coming from countries with stabilized, known, covid situations - until very recently.

Having to be tested? My heart bleeds.

China bashing is a vote-winner in many countries.

Let's not kid ourselves. China is not the most popular country in many of the countries imposing restrictions. We can come up with all the epidemiological reasons we want but let's not lose track of that simple fact.

Answer 3

Just because a country has cases of covid doesn't mean that they want to limit new cases that come in regardless of how many cases that may be. If people with covid are traveling about the country they are more likely to spread it to more people who will also continue spreading it as they travel. A disease has a higher chance of expanding to a larger area if it gets a chance to spread in areas such as airports that will have people traveling all over the country if not the world

In the end it isn't about numbers but the chance to spread it to a larger area based on where they would come into contact with others.

Answer 4

It's an easy way to pretend they are doing something.

People want the government to make COVID go away, but they don't want to have to change anything about their own behaviour.

By placing COVID-lowering requirements on those other people who travel into the country (a group which conveniently I am not a part of) I get to feel like something is being done about COVID, without having to change my behaviour.

Whether or not COVID actually goes away is irrelevant, as long as the feeling of doing something exists.