Phòng Coronavirus: Vì sao phải cách ly 14 ngày?

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Noah Carl provides further evidence that Covid-19 is indeed seasonal. A slice:

Bishop’s criticisms of the Imperial College model are well-taken. In the remainder of this essay, I want to present additional evidence for the seasonality (từng thời vụ; thay đổi theo mùa; xảy ra trong một mùa riêng biệt) of COVID-19. Before looking at studies that deal specifically with COVID-19, it is worth mentioning that other human coronaviruses are known to be seasonal, with the peak (đỉnh điểm) of infections (nhiễm) occurring in February (in the northern hemisphere (bắc bán cầu)). As one recent study – which analysed eight years of data on a cohort in Michigan – concluded, “Coronaviruses are sharply seasonal”. Hence it would be somewhat surprising if COVID-19 didn’t behave in the same way.

There are several mechanisms that may account for the seasonality of coronaviruses. The first is simply that people spend more time indoors in the winter, leading to more opportunities for transmission. A second is that respiratory (thuộc hô hấp) droplets (giọt bắn) remain airborne for longer in cold weather, so they are more likely to enter someone’s nose or mouth. A third is that blood vessels (mạch máu) constrict (thắt lại, siết lại, bóp lại) in cold temperatures, which may reduce our immune system’s ability to kill viruses in the nasal passage. A fourth is that viral particles may degrade more quickly when exposed to sunlight. And a fifth is that UV light may boost our immune systems by facilitating the production of vitamin D.

Bài trước: Lý do nào người dân Texas vật lộn trong giá buốt?