Pattern of COVID-19 Epidemics in Japan Influenced by Control Measures

Background. COVID-19 has
spread all over the world and has been around for over a year. Among the many epidemic
countries, Japan differed in that avoiding the lockdowns and ask
self-restraint. A huge travel campaign was carried out with a huge
amount of budget, but the number of PCR tests is parsimoniously limited. These
political measures may have influenced the epidemic.

Methods. The increase
or decrease in classes of SARS-CoV2 variants were estimated by analysing the
published sequence with an objective multivariate analysis. This methodology
does not rely on unverifiable assumptions. It observes the samples in multiple
directions, digesting complex differences to be simpler forms. The results were
compared over time with the numbers of confirmed cases, PCR tests, and visitors
from overseas.

Results. There have
been three epidemic peaks in Japan, which were basically caused by domestically
mutated variants. However, due to the relaxation of immigration [小西1] restrictions,
several infective variants have come in from abroad, and they are currently
competing for expansion. Among other countries, there are few other cases where
multiple variants make a peak. The chaotic situation will continue for a while
since currently no effort has been made to find asymptomatic carriers and details
of the vaccination program is undecided.

[小西1]Visiting?

They will not stay long, most
of them came for traveling or business.