COVID-19 pandemic over 2020 (with lockdowns) and 2021 (with vaccinations): similar effects for seasonality and environmental factors
… COVID-19 pandemic has a seasonal behavior
… Hot weather and low humidity can reduce the viral transmission of COVID-19 in boreal summer
… Mean cases in summer 2020 (without vaccines) and 2021 (with vaccines) are statistically equal
… Low temperature and high humidity can increase transmission of COVID-19 during winter period
… COVID-19 seasonality is similar to seasonality of influenza-like illnesses
