Table 1 Summary of findings and grading of quality of evidence

COVID-19 incidence: number of COVID-19 cases/population

2,613,319,533

(13 observational studies)

⨁⨁◯◯

Low^{a, b,c}

RR 0.39

(0.34 to 0.45)

12,268 per 100,000

7,483 less per 100,000

(8,097 less to 6,747 less)

Sex- and age-adjusted COVID-19 mortality: relative risk

(5 observational studies)

⨁◯◯◯

Very low^{a, c,d}

RR 0.36

(0.27 to 0.49)

-

-

Intensive care admission rate: number of admissions to ICU/total number of hospital admissions

627,432

(3 observational studies)

⨁◯◯◯

Very low^{a, d,e}

RR 0.91

(0.74 to 1.13)

31,620 per 100,000

2,846 less per 100,000

(8,221 less to 4,111 more)

Use of Invasive mechanical ventilation: number of patients using IMV/total hospital admissions

627,432

(3 observational studies)

⨁◯◯◯

Very low^{a, c,d}

RR 0.77

(0.70 to 0.84)

19,093 per 100,000

4,391 less per 100,000

(5,728 less to 3,055 less)

COVID-19 hospital mortality: number of deaths/number of people admitted to hospital

627,432

(3 observational studies)

⨁◯◯◯

Very low^{a, c,d}

RR 0.81

(0.54 to 1.23)

15,119 per 100,000

2,873 less per 100,000

(6,955 less to 3,477 more)