The majority of western nations have lifted most if not all COVID restrictions, however we are not seeing a massive rise in serious cases of COVID-19.

Why is it different in China? Do they have a different strain?

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    $\begingroup$ The claim that "we are not seeing a massive rise in serious cases of COVID-19" requires reputable sources. From all the publicly available data I have analyzed, there appears to be no data to support any such claim. Of course, I suppose, one could define "massive" to mean whatever they want, which is why it is best to use scientific terminology and methodology and refrain from using such ambiguous terms. $\endgroup$ Commented Dec 29, 2022 at 9:04

3 Answers 3


There are a number of different reasons, all adding up to the current situation.

  1. The strain: There is not a special strain going on in China, according to different references it is mostly the Omicron BF.7 substrain. This strain is highly transmissible (with reported $R_0$ over 10, meaning each infected person infects on average another 10; the Delta strain (which was also already seen as highly infectious) "only" came to an $R_0$ of 5-6). Additionally this strain has accumulated mutations which allow immune escape, a shorter incubation time.

  2. Covid politics: China went from a very strict zero Covid politics to no restrictions at all in the matter of days. Additionally, testing almost completely stopped. This happened with the rise of the highly contagious variant. People started getting together and spread the virus very fast, leading to the current problems.

  3. Vaccinations: In China only the relatively inefficient Sinovac vaccine has been used, as far as I know only two vaccinations are common, with no preference for the older part of the society. How this vaccination (which happened some time ago mostly) will be able to prevent severe disease and death remains to be seen. However, the vaccination status could be better.

  4. Immune status: Curiously, this point is connected to the zero Covid policy. This lead to many people in the Chinese society having never had contact to SARS-COV2. Without this contact, immunity cannot be built (besides vaccinating), this may be an advantage for other societies which had more contact with the virus, although immunity wanes over time.

  5. Population: All the areas where Covid surges now are urban centers with a really high population density. Additionally public transport leads to a lot of potential contacts.

Every of this point attributes a bit to the current problem, but only the combination made it so severe.


  1. WHO concerned over increasing reports of severe COVID-19 cases in China
  2. COVID spreading faster than ever in China. 800 million could be infected this winter
  3. China’s COVID Wave Is Coming
  4. Omicron BF.7, major strain causing latest outbreak in Beijing, has strong infectious ability: medical expert
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    $\begingroup$ All of them, plus a very dense population and a highly interactive urban dynamic. In each of the biggest cities, subway networks transport more than 10 million passengers per day, and more than 108 billion domestic postal packages last year, etc. $\endgroup$
    – X Zhang
    Commented Dec 27, 2022 at 14:49
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    $\begingroup$ @XZhang Right, I forgot to mention the high population density and dynamics. Thanks, I added this point. $\endgroup$
    – Chris
    Commented Dec 27, 2022 at 15:41
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    $\begingroup$ I think 4. is especially relevant. In Most western countries, a vast majority of the population had Covid. A lot of people even multiple times. Often enough more or less harmless (being out of order for a week) but still built immunity far beyond any vaccine (and most often on top of it). This constant natural re-innoculation keeps numbers low $\endgroup$
    – Hobbamok
    Commented Dec 27, 2022 at 15:58
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    $\begingroup$ @Hobbamok wrote: built immunity far beyond any vaccine - I'm interested in reading about your claim. What are your reputable peer reviewed sources? $\endgroup$ Commented Dec 28, 2022 at 22:43
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    $\begingroup$ @RockPaperLz-MaskitorCasket mate. Calm down. All curent Covid vaccines effectiveness decays. You'll find a source for that easily enough. Any further interaction with the virus (be it live or another shot) increases the immune systems effectiveness. Since anything beyond a 4th shot is not recommended for most people, the constant lowkey reinfections with covid (or successfully defended intrusions of the virus) keeps antibody count high. It's not rocket science. $\endgroup$
    – Hobbamok
    Commented Dec 29, 2022 at 16:15

however we are not seeing a massive rise in serious cases of COVID-19.

Because we've already had a huge Omicron wave in December 2021/January 2022 while China is only reopening today. This means that their population is highly vulnerable to becoming infected with the Omicron variant and they need to go through a massive COVID wave to acquire proper immunity. See the Boston Wastewater data tracking the presence of COVID in the city:

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That giant spike in late 2021 is precisely what's going on in China right now. Note that they're in an even worse shape than the US because <1% of their population was infected prior to December 2022 and their vaccine efficacy is lower compared to Pfizer/Moderna's product. They'll go back to having the same baseline of cases as the US once the initial wave subsides and the herd immunity threshold is reached.

  • $\begingroup$ Did Boston reopen in dec 2021? or did something else caused this sudden rise? $\endgroup$
    – moshevi
    Commented Dec 30, 2022 at 14:42
  • $\begingroup$ @moshevi compared to China Boston was never locked down in earnest and the worst restrictions were dropped by spring 2021. The only thing that happened is Omicron. $\endgroup$ Commented Dec 30, 2022 at 15:12

1/ China hasn't built up natural herd immunity, only 0.1% has had it.

2/ Restrictions are lifting in winter, the worst time to lift them for a low immunity nation.

3/ Some Chinese populations are frustrated by extreme and unreasonable covid rules, they may not quarantine voluntarily after watching the world cup.

4/ China has administered 3,5 billion doses of a fairly effective vaccine, it reduces mortality by 90+ percent, however they may have administered the second dose too long ago in 2020 and 2021 to be very effective today.

5/ Everyone knows that the government gives false information, they don't know what is true and what isn't.

  • $\begingroup$ ad 1) As far as we know, there is no herd immunity to be obtained as the virus can mutate. ad 3) Unfortunately, not following the orders can result in pretty hard restrictions in China, so I doubt this is a major factor. ad 4) The vaccine is far less effictive than other available ones. $\endgroup$
    – suvidu
    Commented Dec 30, 2022 at 13:07
  • $\begingroup$ 1/ that's a fair argument, however the global infection figures with unrestricted contact and without recent injections are 5-10 times lower on new year 2022 than they were exactly one year ago, when there was major vaccination and contact restriction... Even though herd immunity is less than i.e. smallpox, immunity is causing 10x less infections in previously infected populations one year on. 3/ Home quarantine apartment blocks are difficult to police and the restrictions are reducing 4/ the vaccine has 95% reduction in mortality according to current medical sources. $\endgroup$ Commented Dec 30, 2022 at 13:21
  • $\begingroup$ also consider the financial benefits to labs that announce "natural immunity may be insufficiant", because that plays exactly into the hands of pharma bosses that say "boost your immunity with our product (at 10x prices now)" ... Industries love false science that promots their product, i.e. cellulose insulation was banned for 40 years at the profit of fiberglass/rockwool because of a single false study promoted by the rockwool stating a fire risk, which was reverse when they found cellulose has mininal fire risk. $\endgroup$ Commented Dec 31, 2022 at 11:20

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