Five consecutive epidemiological waves of COVID-19: a population-based cross-sectional study on characteristics, policies, and health outcome

1st wave presented mainly w/ respiratory symptoms, GI complaints in the 2nd wave, neurological manifestations with peripheral involvement replaced the gastrointestinal during the 3rd wave, & central nervous system manifestations during the 4th & 5t

1,259/ https://t.co/W5GMRO3EDm

6,926/ Iran (est. current tobacco smoking age 15+ was 10.2% in 2020) Of 328,410 diagnosed with Covid-19, 1.4% had a history of smoking OR (mortality): 0.81 (0.727-0.914) p < 0.001 https://t.co/9G9OYiOJqv