Testing is useful for two reasons - helping people who may have the disease (obviously), and for seroprevalence. Since Japan's testing was so low those seroprevalence statistics are lacking. As we know now, severity of the disease is linked to the overall health of the individual. It's quite possible those waves you call nontrivial were just as large but that the health of the population meant the severity of symptoms (which is what actually makes a wave trivial or not, along with availability of health services) was lower and continued to be lower.
I've been in Japan for the whole of the pandemic and to claim that people were isolated - either from each other or the outside world in any way that is meaningful for disease or contact tracing was of a high level is to contradict reality.
Finally, the article I shared by Bhattacharya and Packalen goes over contact tracing and points out why it is futile in the case of COVID-19, but Martin Kulldorff, Bhattacharya's infamous co-signatory on the Great Barrington Declaration sums it up in two tweets[1][2]:
> Contact tracing, testing and isolation is important against many infectious disease outbreaks, such as Ebola and post-vaccine measles. It is ineffective, naïve and counter-productive against COVID19, influenza, pre-vaccine measles, etc, and by definition, against any pandemic.
> Problems when one or more of: (1) disease is widely spread, (2) there are many mild or asymptomatic cases, (3) there is pre-symptomatic transmission, (4) we cannot identify the first index case in a given population, or how that person got infected.
[1] https://twitter.com/MartinKulldorff/status/13073778096192880...
[2] https://twitter.com/MartinKulldorff/status/13073812979171614...
That's why you should not look at individual data points in isolation.
Based on the numbers that were reported, the COVID waves that hit Japan became worse over time. That already suggests that the waves that hit in 2020 and 2021 were not particularly big.
If you compare internationally, you can find similar patterns in countries that mostly managed to avoid COVID in 2020 and 2021 before succumbing to Omicron. In contrast, countries that were hit bad early in the pandemic had a lot of infections but fewer deaths from Omicron, largely due to existing immunity.
And there's the reason testing to get seroprevalence data is so important, because what follows that sentence is pure speculation.
> If you compare internationally, you can find similar patterns in countries that mostly managed to avoid COVID in 2020 and 2021 before succumbing to Omicron.
Again,
- Japan had no internal lockdown
- International travel still occurred
- Contact tracing does not work in a pandemic, especially one for a respiratory virus that has already spread[1], closing the barn doors after the horse has bolted is not a valid proposition as actual seroprevalence testing showed in early 2020 that contradicted official figures:
> Results: ... These numbers were 396 to 858-fold more than confirmed cases with PCR testing in Kobe City.
> Conclusions: Our cross-sectional serological study suggests that the number of people with seropositive for SARS-CoV-2 infection in Kobe, Japan is far more than the confirmed cases by PCR testing.
There are more of these types of study[2][3], if you care to look, that hint more that heavily at the reality.
> Results: We estimated that as of December 31, 2021, 3.07 million (CrI: 2.05-4.24 million) people had been infected in Japan, which is 1.77 times higher than the 1.73 million reported cases. Our meta-analysis confirmed that these findings were consistent with the intermittent seroprevalence studies conducted in Japan.
and
> In conclusion, our cross-sectional serological study suggests that the actual number of people with SARS-CoV-2 infection in Kobe, Japan was estimated to be lower than our previous study, yet was more than the confirmed cases by PCR testing.
Lockdown logic is not valid, in theory or reality. Stay slim, stay active and your country too can remain largely unaffected[4], in a way that is statistically significant - to the point it hits one over the head with a hammer - and backed up by actual evidence, unlike lockdowns and masks.
> There was a consistent dose‒response association across lower physical activity categories, with the strongest association comparing the always active with the always inactive category. Patients in the always inactive category (median EVS≤10 minutes/week) had 91% higher odds of hospitalization (OR=1.91; 95% CI=1.68, 2.17), 139% higher odds of a deterioration event (Appendix Figure 2, available online) (OR=2.39; 95% CI=1.94, 2.94), and 291% higher odds of death (OR=3.91; 95% CI=3.01, 5.07) than patients in the always active category.
and from[5], the most succinct and blunt way to put it:
> Is overweight associated with the severity of COVID-19 and the need for hospital treatment?
> Yes.
The figures speak for themselves. Worth a read, I highly recommend it.
Finally, this assertion of yours is patently false:
> but fewer deaths from Omicron, largely due to existing immunity.
South Africa has entered the chat.
[1] https://pubmed.ncbi.nlm.nih.gov/33898863/#article-details
[2] https://pubmed.ncbi.nlm.nih.gov/35961504/#article-details
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9191319/#main-c...
[4] https://www.ajpmonline.org/article/S0749-3797(22)00526-8/ful...
[5] https://www.worldobesity.org/resources/resource-library/covi...
50% of reported COVID deaths in Japan have occurred since April 2022. In most Western countries, the median death was about a year earlier. That difference suggests that whatever Japan did in 2020-2021, it helped them to avoid infections during that time. Differences in case mortality rates don't explain numbers like that.
Infectious diseases do not care about pandemics and other administrative classifications. Contact tracing works as long as the rate of new infections remains low enough. For example, most Nordic countries managed to enjoy a relatively normal summer 2020, because contact tracing was able to keep up with new infections for several months.
Getting outside, exercising, and not being overweight.
> Infectious diseases do not care about pandemics and other administrative classifications.
Yes, what epidemiologists know should have no place in a discussion like this, neither should the facts about the effect size of fitness level and obesity being greater than that of vaccines, for instance, that kind of thing would be far too inconvenient. We should replace it with speculation that doesn’t actually fit reality.
Do you mean that the Japanese stopped going outside, stopped exercising, and became overweight in 2022? After all, COVID deaths went up there, as opposed to most other countries.
Weirdly, before the border restrictions that did exist were lifted.
> as opposed to most other countries
That's a stretch[1], but by all means, feel free to claim that a highly virulent respiratory virus transmission rate and a large population's immune response should remain uniform. Make no effort to check excess death figures either. As they say, never interfere with an enemy while he’s in the process of destroying himself.
Meanwhile, an article[2] early in the pandemic that looked at why Japan was doing so well has this to say:
> Nor has Japan had a lockdown on the scale or severity of Europe. In early April, the government ordered a state of emergency. But the stay-at-home request was voluntary. Non-essential businesses were asked to close, but there was no legal penalty for refusing.
> Many paragons of Covid strategy, such as New Zealand and Vietnam, used tough measures including closing borders, tight lockdowns, large-scale testing and strict quarantines - but Japan did none of that.
and later in the article, after much speculation:
> A recent report by the United States Centers for Disease Control and Prevention found people with underlying medical conditions such as heart disease, obesity and diabetes are six times more likely to be hospitalised if they get Covid-19 and 12 times more likely to die.
> Japan has the lowest rates of coronary heart disease and obesity in the developed world. Still, scientists insist such vital signs do not explain everything.
> "Those kinds of physical differences may have some effect but I think the other areas are more important. We've learned from Covid that there is no simple explanation for any of the phenomena that we're seeing. It's a lot of factors contributing to the final outcome," says Prof Fukuda.
Well, the professor was shown to be too conservative as we now have more data and know how strong the effect of these physical differences are. You know, facts, those inconvenient things that are better than (incessant) speculation. "It's a lot of factors" is true but attributing a cause to factors that don't exist is a weakpoint in any argument.
[1] https://ourworldindata.org/explorers/coronavirus-data-explor...
[2] https://www.bbc.com/news/world-asia-53188847#main-heading
Comparing statistics between countries is difficult, because data definitions vary, old definitions may no longer be appropriate, and there are all kinds of measurement errors. However, if you compare multiple statistics (e.g. cases, deaths, hospitalizations, positivity rate) and look how they change over time, you can get some idea.
According to various per capita figures, Japan had the first nontrivial wave in August/September 2021. That wave was maybe half as bad as in the US and Europe around the same time. Then there was an Omicron wave in early 2022, which was bigger than the previous one but much smaller than in the US and Europe a bit earlier. Then, in August/September 2022, there was a major wave similar to the initial Omicron wave in other countries.
Contact tracing is mostly about public health personnel interviewing those who test positive and actively seeking out their contacts. And then using targeted measures to isolate those who may have been exposed to the virus. Apps may be of limited use, but as far as I know, they were not a significant part of any successful contact tracing effort (except maybe in China).
Infectious diseases spread exponentially before they get out of control. Measures used to control them lower the base, and there is a qualitative change around 1. As a consequence, if you look at any individual measure (e.g. mask use, border closures, lockdowns, contact tracing), it is likely to be ineffective. However, if you use multiple "ineffective" measures at the same time, the combination may be effective.