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.


4 Answers 4


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.

  • Why wouldn't these new variants emerge just as easily among the 6.8 billion people who don't live in China? All of these countries have long "let it rip" and are seeing tens of millions of new cases combined on a daily basis. Jan 4, 2023 at 17:16
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    @JonathanReez re variants, they can and are appearing elsewhere as well, the main source of concern here is that China had hidden its actual infection level(s) behind zeroes in statistics, comparing to EU and many other countries exposing some "real" values. This, multiplied by Chinese urban density and overall weather in the densely inhabited area that provides less environmental restrictions to aerosol-based virus transfer, makes it easier for an emerging variant that's more infectitious to spread wide than say in Europe.
    – Vesper
    Jan 4, 2023 at 17:54
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    @JonathanReez true but it's easier for a new variant to spread where there's less control and more hosts in close vicinity.
    – Vesper
    Jan 4, 2023 at 17:58
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    @JonathanReez Most countries where many citizens can afford large-scale international tourism (the EU, the UK, the US, Japan, Korea, Israel, etc.) have proper testing and transparency in place. If you want to add politics, treat the words "proper" and "transparency" as perceived among these countries. China has a lot of people who can afford international travel but it lacks, at least, transparency. This gives you a pretty founded option for why the countries mentioned above might not want A LOT OF travelers from China right at the moment when there are A LOT OF new cases in China.
    – Igor
    Jan 4, 2023 at 18:41
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    @JonathanReez As for the other 6.8b people are those going to have very active international travel to the above-mentioned countries in the upcoming weeks compared to a few weeks before? The devil you know is better than the new one. Particularly, when most of the Chinese population hasn't been sick before and the immunization effects are questionable (vaccine efficiency is lower, but also we have the percentage of unvaccinated, questions about boosters, etc.).
    – Igor
    Jan 4, 2023 at 18:46

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.

  • Your answer is definitely better than mine, so I upvoted it. But for your last part, some of the countries don't seem to have troubles with China at all (at least, I haven't heard of any) and still imposed the harshest restrictions: a total ban on Chinese travelers in Morocco. Plus, if I remember correctly, EU countries also had restrictions for the Americans when there was a huge spike of cases in the US while they seem to have fine relations. Plus, some of these countries imposed the same restrictions not only on China (India imposed on Japan). So I think the last part is less relevant here.
    – Igor
    Jan 4, 2023 at 20:29
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    Yes, Canada had an India ban for example. But it is still true that a number of restrictive countries dont like China much these days. And putting in place covid restrictions before early/mid 2022 (pre mass vaccinations and and pre passing of Omicron wave) - is not that comparable to putting in place covid restrictions in 2023. Don't think we can fully separate the medical aspect from the political but I can't say how much each weighs. Jan 4, 2023 at 20:41
  • IMHO, the medical uncertainty as you described so well in the first part, has the biggest weight. But still, it's politics SE :)
    – Igor
    Jan 4, 2023 at 20:45
  • well, your answer is better on medicals so +1 back Jan 4, 2023 at 20:47

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.

  • Shouldn't testing be required for all arrivals then? After all, the EU+UK combined probably have at least 1m new cases every single day. Jan 4, 2023 at 17:19
  • And I'm confused about your "larger area" comment - which area still doesn't have a massive number of COVID cases? All 50 states and all US territories have plenty of COVID cases. Jan 4, 2023 at 17:20
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    @JonathanReez Yes, I would agree with you that it should be required for more areas that have an issue with covid. As for the numbers concerns it doesn't matter how many cases that an area has there is and should be concern about bringing in new cases to an area. And when you have travelers who are moving through airports and other major travel hubs it makes it that much easier for a single person to spread their infection out over a larger area.
    – Joe W
    Jan 4, 2023 at 17:27
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    @JonathanReez What is there to be confused about the number of cases in the US being irrelevant to wanting to test people who travel there to prevent new cases from entering the country? It doesn't make any sense to allow new sources for infection if you are trying to control the numbers.
    – Joe W
    Jan 4, 2023 at 17:41
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    @JonathanReez Why do you think that in country controls mean that they are okay with more cases coming in from out of the country? And as mentioned in comments on your question there are a lot more countries then just the US that have testing requirements on people coming from China.
    – Joe W
    Jan 4, 2023 at 18:09

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.

  • Plenty of people also saying that covid is a hoax and want nothing to be done about it.
    – Joe W
    Jan 4, 2023 at 19:45
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    @JoeW yes, what is the relevance? Jan 4, 2023 at 20:06
  • Because don't want them to be pretending to do anything at all and it isn't just people pretending to do something?
    – Joe W
    Jan 4, 2023 at 20:23
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    @JoeW even the minority who thinks COVID is a hoax doesn't care a whole lot if things are done that don't affect them Jan 4, 2023 at 20:48

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