Не сезонный
Jan. 28th, 2022 09:48 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
chuka_lisРабота, в которой проанализированы паттерны протекания ковидных волн в 30 странах (в разных географичесикх регионах)с использованием спектрального анализа Фурье, показала, что в каждой стране, волны повторяются со своей периодичностью (от 3 до 9 мес), что связано с другими факторами, чем климат (сезоны осень зима весна лето).
Так что ковид сезонным заболеванием- не является.
We chose 30 countries from different geographies and climates. With a discrete Fourier transform, we performed a spectral analysis of the series of the daily SARS-CoV-2 infections, looking for peaks in the frequency spectrum that could correspond to a recurrent cycle of a given length. This analysis allows to question whether COVID-19 outbreaks have an observable seasonal periodicity. We focused our study on a wide selection of worldwide countries, chosen following the Köppen climate classification [13]. This classification divides climates into five main groups, where each group is considered based on seasonal precipitation and temperatures. The five main groups are: tropical (A), dry (B), temperate (C), continental (D) and polar (E). We analyzed 30 different countries that cover all the five groups, with several of the selected countries belonging to two or more groups, given their vast geography (e.g., India, Russia, and the USA, to cite a few). The complete list of the 30 countries follow below, each with its prevalent type of climates: Argentina (B, C), Australia (A, B, C), Austria (D, E), Belgium (C), Brazil (A, C), Canada (C, D, E) Chile (B, C, D), Colombia (A, C), Croatia (C), Denmark (D), France (C), Germany (C, D), Hungary (D), India (A, B, C, D), Indonesia (A), Italy (B, C), Japan (A, C, D), Mexico (A, B, C), Morocco (B, C), Norway (D, E), Portugal (C), Russia (D, E), Saudi Arabia (B), South Africa (B, C), South Korea (C, D), Spain (B, C), Sweden (D, E), Turkey (B, C, D), UK (C) and USA (B, C, D, E). Results: All the 30 investigated countries see the recurrence of at least one COVID-19 wave, repeating over a period in the range 3 - 9 months, with a peak of magnitude at least half as large as that of the highest peak ever experienced since the beginning of the pandemic until December 2021. We also computed the distance in days between the two higher peaks in each country, and then we averaged those values over the 30 countries, yielding a mean of 190 days (SD 100). This suggests that outbreaks may repeat with cycles of different lengths, without a precisely predictable seasonality of one year. Seasonality typically refers to a single, recurring pattern with a fixed frequency. The results we achieved highlight how, with COVID-19, strong evidence of a seasonal pattern that repeats over a one-year fixed period cannot be found. Instead, several repeating outbreaks, not necessarily occurring with a fixed frequency, can be observed. In particular, the Fourier spectral analysis of the time series of the SARS-CoV-2 cases of all the 30 countries we have studied has revealed the recurrence of at least one COVID-19 wave (often two or more), repeating over a variable period, in the range 3 - 9 months, with peaks of magnitude comparable to that of the highest peak ever experienced since the beginning of the pandemic until December 2021. Indeed, the situation is more complicated than previous studies have revealed. In fact, while some of them consider COVID-19 as a seasonal low-temperature infection, the precise role of temperature, humidity, and exposition to UV radiation remains poorly understood. From this perspective, our study has tried to follow an alternative path with spectral analysis of the series of the daily SARS-CoV-2 cases, while looking for peaks in the frequency spectrum to understand the presence of repeating cycles and quantify their lengths. Conclusion: Our findings suggest that COVID-19 outbreaks are likely to occur worldwide, with cycles of repetition of variable lengths. Our Fourier analysis with 30 different countries has not found evidence in favor of a seasonality that recurs over one-year period, solely or with a precisely fixed periodicity.
Так что ковид сезонным заболеванием- не является.
We chose 30 countries from different geographies and climates. With a discrete Fourier transform, we performed a spectral analysis of the series of the daily SARS-CoV-2 infections, looking for peaks in the frequency spectrum that could correspond to a recurrent cycle of a given length. This analysis allows to question whether COVID-19 outbreaks have an observable seasonal periodicity. We focused our study on a wide selection of worldwide countries, chosen following the Köppen climate classification [13]. This classification divides climates into five main groups, where each group is considered based on seasonal precipitation and temperatures. The five main groups are: tropical (A), dry (B), temperate (C), continental (D) and polar (E). We analyzed 30 different countries that cover all the five groups, with several of the selected countries belonging to two or more groups, given their vast geography (e.g., India, Russia, and the USA, to cite a few). The complete list of the 30 countries follow below, each with its prevalent type of climates: Argentina (B, C), Australia (A, B, C), Austria (D, E), Belgium (C), Brazil (A, C), Canada (C, D, E) Chile (B, C, D), Colombia (A, C), Croatia (C), Denmark (D), France (C), Germany (C, D), Hungary (D), India (A, B, C, D), Indonesia (A), Italy (B, C), Japan (A, C, D), Mexico (A, B, C), Morocco (B, C), Norway (D, E), Portugal (C), Russia (D, E), Saudi Arabia (B), South Africa (B, C), South Korea (C, D), Spain (B, C), Sweden (D, E), Turkey (B, C, D), UK (C) and USA (B, C, D, E). Results: All the 30 investigated countries see the recurrence of at least one COVID-19 wave, repeating over a period in the range 3 - 9 months, with a peak of magnitude at least half as large as that of the highest peak ever experienced since the beginning of the pandemic until December 2021. We also computed the distance in days between the two higher peaks in each country, and then we averaged those values over the 30 countries, yielding a mean of 190 days (SD 100). This suggests that outbreaks may repeat with cycles of different lengths, without a precisely predictable seasonality of one year. Seasonality typically refers to a single, recurring pattern with a fixed frequency. The results we achieved highlight how, with COVID-19, strong evidence of a seasonal pattern that repeats over a one-year fixed period cannot be found. Instead, several repeating outbreaks, not necessarily occurring with a fixed frequency, can be observed. In particular, the Fourier spectral analysis of the time series of the SARS-CoV-2 cases of all the 30 countries we have studied has revealed the recurrence of at least one COVID-19 wave (often two or more), repeating over a variable period, in the range 3 - 9 months, with peaks of magnitude comparable to that of the highest peak ever experienced since the beginning of the pandemic until December 2021. Indeed, the situation is more complicated than previous studies have revealed. In fact, while some of them consider COVID-19 as a seasonal low-temperature infection, the precise role of temperature, humidity, and exposition to UV radiation remains poorly understood. From this perspective, our study has tried to follow an alternative path with spectral analysis of the series of the daily SARS-CoV-2 cases, while looking for peaks in the frequency spectrum to understand the presence of repeating cycles and quantify their lengths. Conclusion: Our findings suggest that COVID-19 outbreaks are likely to occur worldwide, with cycles of repetition of variable lengths. Our Fourier analysis with 30 different countries has not found evidence in favor of a seasonality that recurs over one-year period, solely or with a precisely fixed periodicity.
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