Epidemiology

Cases have been reported across all continents since the beginning of the pandemic. Over 600 million confirmed cases and over 6.5 million deaths have been reported globally.[22]

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Updated case counts are available from the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC):

Data from the CDC between February 2020 to September 2021 indicate the following estimated rates of disease outcomes in the US:[23]

  • Infection: 44,650 per 1000,000 (44.6%)

  • Symptomatic illness: 37,764 per 100,000 (37.8%)

  • Hospitalization: 2286 per 100,000 (2.3%)

  • Death: 281 per 100,000 (0.28%).

Older people ≥70 years of age and males are at increased risk for infection and severe disease.[24] Adolescents appear to have similar susceptibility to infection as adults, and children have a lower susceptibility. However, evidence is conflicting and the detailed relationship between age and susceptibility to infection requires further investigation.[25][26] Unlike adults, children do not seem to be at higher risk for severe disease based on age or sex.[27] Variants may spread more effectively and rapidly among young children compared with the wild-type virus, although hospitalization rates decreased.[28][29]

The incidence of infection in healthcare workers ranged from 0% to 49.6%, and the prevalence of seropositivity ranged from 1.6% to 31.6%. There was no association between age, sex, or healthcare worker role (i.e., nurse versus physician) and the risk for infection, based on moderate-certainty evidence. There was an association between Black race or Hispanic ethnicity and increased risk for infection compared with White race or non-Hispanic ethnicity, based on moderate-certainty evidence. There was an association between use of personal protective equipment and decreased risk for infection, based on moderate-certainty evidence.[30][31]

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